package yaml import ( "bytes" "fmt" ) // Introduction // ************ // // The following notes assume that you are familiar with the YAML specification // (http://yaml.org/spec/1.2/spec.html). We mostly follow it, although in // some cases we are less restrictive that it requires. // // The process of transforming a YAML stream into a sequence of events is // divided on two steps: Scanning and Parsing. // // The Scanner transforms the input stream into a sequence of tokens, while the // parser transform the sequence of tokens produced by the Scanner into a // sequence of parsing events. // // The Scanner is rather clever and complicated. The Parser, on the contrary, // is a straightforward implementation of a recursive-descendant parser (or, // LL(1) parser, as it is usually called). // // Actually there are two issues of Scanning that might be called "clever", the // rest is quite straightforward. The issues are "block collection start" and // "simple keys". Both issues are explained below in details. // // Here the Scanning step is explained and implemented. We start with the list // of all the tokens produced by the Scanner together with short descriptions. // // Now, tokens: // // STREAM-START(encoding) # The stream start. // STREAM-END # The stream end. // VERSION-DIRECTIVE(major,minor) # The '%YAML' directive. // TAG-DIRECTIVE(handle,prefix) # The '%TAG' directive. // DOCUMENT-START # '---' // DOCUMENT-END # '...' // BLOCK-SEQUENCE-START # Indentation increase denoting a block // BLOCK-MAPPING-START # sequence or a block mapping. // BLOCK-END # Indentation decrease. // FLOW-SEQUENCE-START # '[' // FLOW-SEQUENCE-END # ']' // BLOCK-SEQUENCE-START # '{' // BLOCK-SEQUENCE-END # '}' // BLOCK-ENTRY # '-' // FLOW-ENTRY # ',' // KEY # '?' or nothing (simple keys). // VALUE # ':' // ALIAS(anchor) # '*anchor' // ANCHOR(anchor) # '&anchor' // TAG(handle,suffix) # '!handle!suffix' // SCALAR(value,style) # A scalar. // // The following two tokens are "virtual" tokens denoting the beginning and the // end of the stream: // // STREAM-START(encoding) // STREAM-END // // We pass the information about the input stream encoding with the // STREAM-START token. // // The next two tokens are responsible for tags: // // VERSION-DIRECTIVE(major,minor) // TAG-DIRECTIVE(handle,prefix) // // Example: // // %YAML 1.1 // %TAG ! !foo // %TAG !yaml! tag:yaml.org,2002: // --- // // The correspoding sequence of tokens: // // STREAM-START(utf-8) // VERSION-DIRECTIVE(1,1) // TAG-DIRECTIVE("!","!foo") // TAG-DIRECTIVE("!yaml","tag:yaml.org,2002:") // DOCUMENT-START // STREAM-END // // Note that the VERSION-DIRECTIVE and TAG-DIRECTIVE tokens occupy a whole // line. // // The document start and end indicators are represented by: // // DOCUMENT-START // DOCUMENT-END // // Note that if a YAML stream contains an implicit document (without '---' // and '...' indicators), no DOCUMENT-START and DOCUMENT-END tokens will be // produced. // // In the following examples, we present whole documents together with the // produced tokens. // // 1. An implicit document: // // 'a scalar' // // Tokens: // // STREAM-START(utf-8) // SCALAR("a scalar",single-quoted) // STREAM-END // // 2. An explicit document: // // --- // 'a scalar' // ... // // Tokens: // // STREAM-START(utf-8) // DOCUMENT-START // SCALAR("a scalar",single-quoted) // DOCUMENT-END // STREAM-END // // 3. Several documents in a stream: // // 'a scalar' // --- // 'another scalar' // --- // 'yet another scalar' // // Tokens: // // STREAM-START(utf-8) // SCALAR("a scalar",single-quoted) // DOCUMENT-START // SCALAR("another scalar",single-quoted) // DOCUMENT-START // SCALAR("yet another scalar",single-quoted) // STREAM-END // // We have already introduced the SCALAR token above. The following tokens are // used to describe aliases, anchors, tag, and scalars: // // ALIAS(anchor) // ANCHOR(anchor) // TAG(handle,suffix) // SCALAR(value,style) // // The following series of examples illustrate the usage of these tokens: // // 1. A recursive sequence: // // &A [ *A ] // // Tokens: // // STREAM-START(utf-8) // ANCHOR("A") // FLOW-SEQUENCE-START // ALIAS("A") // FLOW-SEQUENCE-END // STREAM-END // // 2. A tagged scalar: // // !!float "3.14" # A good approximation. // // Tokens: // // STREAM-START(utf-8) // TAG("!!","float") // SCALAR("3.14",double-quoted) // STREAM-END // // 3. Various scalar styles: // // --- # Implicit empty plain scalars do not produce tokens. // --- a plain scalar // --- 'a single-quoted scalar' // --- "a double-quoted scalar" // --- |- // a literal scalar // --- >- // a folded // scalar // // Tokens: // // STREAM-START(utf-8) // DOCUMENT-START // DOCUMENT-START // SCALAR("a plain scalar",plain) // DOCUMENT-START // SCALAR("a single-quoted scalar",single-quoted) // DOCUMENT-START // SCALAR("a double-quoted scalar",double-quoted) // DOCUMENT-START // SCALAR("a literal scalar",literal) // DOCUMENT-START // SCALAR("a folded scalar",folded) // STREAM-END // // Now it's time to review collection-related tokens. We will start with // flow collections: // // FLOW-SEQUENCE-START // FLOW-SEQUENCE-END // FLOW-MAPPING-START // FLOW-MAPPING-END // FLOW-ENTRY // KEY // VALUE // // The tokens FLOW-SEQUENCE-START, FLOW-SEQUENCE-END, FLOW-MAPPING-START, and // FLOW-MAPPING-END represent the indicators '[', ']', '{', and '}' // correspondingly. FLOW-ENTRY represent the ',' indicator. Finally the // indicators '?' and ':', which are used for denoting mapping keys and values, // are represented by the KEY and VALUE tokens. // // The following examples show flow collections: // // 1. A flow sequence: // // [item 1, item 2, item 3] // // Tokens: // // STREAM-START(utf-8) // FLOW-SEQUENCE-START // SCALAR("item 1",plain) // FLOW-ENTRY // SCALAR("item 2",plain) // FLOW-ENTRY // SCALAR("item 3",plain) // FLOW-SEQUENCE-END // STREAM-END // // 2. A flow mapping: // // { // a simple key: a value, # Note that the KEY token is produced. // ? a complex key: another value, // } // // Tokens: // // STREAM-START(utf-8) // FLOW-MAPPING-START // KEY // SCALAR("a simple key",plain) // VALUE // SCALAR("a value",plain) // FLOW-ENTRY // KEY // SCALAR("a complex key",plain) // VALUE // SCALAR("another value",plain) // FLOW-ENTRY // FLOW-MAPPING-END // STREAM-END // // A simple key is a key which is not denoted by the '?' indicator. Note that // the Scanner still produce the KEY token whenever it encounters a simple key. // // For scanning block collections, the following tokens are used (note that we // repeat KEY and VALUE here): // // BLOCK-SEQUENCE-START // BLOCK-MAPPING-START // BLOCK-END // BLOCK-ENTRY // KEY // VALUE // // The tokens BLOCK-SEQUENCE-START and BLOCK-MAPPING-START denote indentation // increase that precedes a block collection (cf. the INDENT token in Python). // The token BLOCK-END denote indentation decrease that ends a block collection // (cf. the DEDENT token in Python). However YAML has some syntax pecularities // that makes detections of these tokens more complex. // // The tokens BLOCK-ENTRY, KEY, and VALUE are used to represent the indicators // '-', '?', and ':' correspondingly. // // The following examples show how the tokens BLOCK-SEQUENCE-START, // BLOCK-MAPPING-START, and BLOCK-END are emitted by the Scanner: // // 1. Block sequences: // // - item 1 // - item 2 // - // - item 3.1 // - item 3.2 // - // key 1: value 1 // key 2: value 2 // // Tokens: // // STREAM-START(utf-8) // BLOCK-SEQUENCE-START // BLOCK-ENTRY // SCALAR("item 1",plain) // BLOCK-ENTRY // SCALAR("item 2",plain) // BLOCK-ENTRY // BLOCK-SEQUENCE-START // BLOCK-ENTRY // SCALAR("item 3.1",plain) // BLOCK-ENTRY // SCALAR("item 3.2",plain) // BLOCK-END // BLOCK-ENTRY // BLOCK-MAPPING-START // KEY // SCALAR("key 1",plain) // VALUE // SCALAR("value 1",plain) // KEY // SCALAR("key 2",plain) // VALUE // SCALAR("value 2",plain) // BLOCK-END // BLOCK-END // STREAM-END // // 2. Block mappings: // // a simple key: a value # The KEY token is produced here. // ? a complex key // : another value // a mapping: // key 1: value 1 // key 2: value 2 // a sequence: // - item 1 // - item 2 // // Tokens: // // STREAM-START(utf-8) // BLOCK-MAPPING-START // KEY // SCALAR("a simple key",plain) // VALUE // SCALAR("a value",plain) // KEY // SCALAR("a complex key",plain) // VALUE // SCALAR("another value",plain) // KEY // SCALAR("a mapping",plain) // BLOCK-MAPPING-START // KEY // SCALAR("key 1",plain) // VALUE // SCALAR("value 1",plain) // KEY // SCALAR("key 2",plain) // VALUE // SCALAR("value 2",plain) // BLOCK-END // KEY // SCALAR("a sequence",plain) // VALUE // BLOCK-SEQUENCE-START // BLOCK-ENTRY // SCALAR("item 1",plain) // BLOCK-ENTRY // SCALAR("item 2",plain) // BLOCK-END // BLOCK-END // STREAM-END // // YAML does not always require to start a new block collection from a new // line. If the current line contains only '-', '?', and ':' indicators, a new // block collection may start at the current line. The following examples // illustrate this case: // // 1. Collections in a sequence: // // - - item 1 // - item 2 // - key 1: value 1 // key 2: value 2 // - ? complex key // : complex value // // Tokens: // // STREAM-START(utf-8) // BLOCK-SEQUENCE-START // BLOCK-ENTRY // BLOCK-SEQUENCE-START // BLOCK-ENTRY // SCALAR("item 1",plain) // BLOCK-ENTRY // SCALAR("item 2",plain) // BLOCK-END // BLOCK-ENTRY // BLOCK-MAPPING-START // KEY // SCALAR("key 1",plain) // VALUE // SCALAR("value 1",plain) // KEY // SCALAR("key 2",plain) // VALUE // SCALAR("value 2",plain) // BLOCK-END // BLOCK-ENTRY // BLOCK-MAPPING-START // KEY // SCALAR("complex key") // VALUE // SCALAR("complex value") // BLOCK-END // BLOCK-END // STREAM-END // // 2. Collections in a mapping: // // ? a sequence // : - item 1 // - item 2 // ? a mapping // : key 1: value 1 // key 2: value 2 // // Tokens: // // STREAM-START(utf-8) // BLOCK-MAPPING-START // KEY // SCALAR("a sequence",plain) // VALUE // BLOCK-SEQUENCE-START // BLOCK-ENTRY // SCALAR("item 1",plain) // BLOCK-ENTRY // SCALAR("item 2",plain) // BLOCK-END // KEY // SCALAR("a mapping",plain) // VALUE // BLOCK-MAPPING-START // KEY // SCALAR("key 1",plain) // VALUE // SCALAR("value 1",plain) // KEY // SCALAR("key 2",plain) // VALUE // SCALAR("value 2",plain) // BLOCK-END // BLOCK-END // STREAM-END // // YAML also permits non-indented sequences if they are included into a block // mapping. In this case, the token BLOCK-SEQUENCE-START is not produced: // // key: // - item 1 # BLOCK-SEQUENCE-START is NOT produced here. // - item 2 // // Tokens: // // STREAM-START(utf-8) // BLOCK-MAPPING-START // KEY // SCALAR("key",plain) // VALUE // BLOCK-ENTRY // SCALAR("item 1",plain) // BLOCK-ENTRY // SCALAR("item 2",plain) // BLOCK-END // // Ensure that the buffer contains the required number of characters. // Return true on success, false on failure (reader error or memory error). func cache(parser *yaml_parser_t, length int) bool { // [Go] This was inlined: !cache(A, B) -> unread < B && !update(A, B) return parser.unread >= length || yaml_parser_update_buffer(parser, length) } // Advance the buffer pointer. func skip(parser *yaml_parser_t) { parser.mark.index++ parser.mark.column++ parser.unread-- parser.buffer_pos += width(parser.buffer[parser.buffer_pos]) } func skip_line(parser *yaml_parser_t) { if is_crlf(parser.buffer, parser.buffer_pos) { parser.mark.index += 2 parser.mark.column = 0 parser.mark.line++ parser.unread -= 2 parser.buffer_pos += 2 } else if is_break(parser.buffer, parser.buffer_pos) { parser.mark.index++ parser.mark.column = 0 parser.mark.line++ parser.unread-- parser.buffer_pos += width(parser.buffer[parser.buffer_pos]) } } // Copy a character to a string buffer and advance pointers. func read(parser *yaml_parser_t, s []byte) []byte { w := width(parser.buffer[parser.buffer_pos]) if w == 0 { panic("invalid character sequence") } if len(s) == 0 { s = make([]byte, 0, 32) } if w == 1 && len(s)+w <= cap(s) { s = s[:len(s)+1] s[len(s)-1] = parser.buffer[parser.buffer_pos] parser.buffer_pos++ } else { s = append(s, parser.buffer[parser.buffer_pos:parser.buffer_pos+w]...) parser.buffer_pos += w } parser.mark.index++ parser.mark.column++ parser.unread-- return s } // Copy a line break character to a string buffer and advance pointers. func read_line(parser *yaml_parser_t, s []byte) []byte { buf := parser.buffer pos := parser.buffer_pos switch { case buf[pos] == '\r' && buf[pos+1] == '\n': // CR LF . LF s = append(s, '\n') parser.buffer_pos += 2 parser.mark.index++ parser.unread-- case buf[pos] == '\r' || buf[pos] == '\n': // CR|LF . LF s = append(s, '\n') parser.buffer_pos += 1 case buf[pos] == '\xC2' && buf[pos+1] == '\x85': // NEL . LF s = append(s, '\n') parser.buffer_pos += 2 case buf[pos] == '\xE2' && buf[pos+1] == '\x80' && (buf[pos+2] == '\xA8' || buf[pos+2] == '\xA9'): // LS|PS . LS|PS s = append(s, buf[parser.buffer_pos:pos+3]...) parser.buffer_pos += 3 default: return s } parser.mark.index++ parser.mark.column = 0 parser.mark.line++ parser.unread-- return s } // Get the next token. func yaml_parser_scan(parser *yaml_parser_t, token *yaml_token_t) bool { // Erase the token object. *token = yaml_token_t{} // [Go] Is this necessary? // No tokens after STREAM-END or error. if parser.stream_end_produced || parser.error != yaml_NO_ERROR { return true } // Ensure that the tokens queue contains enough tokens. if !parser.token_available { if !yaml_parser_fetch_more_tokens(parser) { return false } } // Fetch the next token from the queue. *token = parser.tokens[parser.tokens_head] parser.tokens_head++ parser.tokens_parsed++ parser.token_available = false if token.typ == yaml_STREAM_END_TOKEN { parser.stream_end_produced = true } return true } // Set the scanner error and return false. func yaml_parser_set_scanner_error(parser *yaml_parser_t, context string, context_mark yaml_mark_t, problem string) bool { parser.error = yaml_SCANNER_ERROR parser.context = context parser.context_mark = context_mark parser.problem = problem parser.problem_mark = parser.mark return false } func yaml_parser_set_scanner_tag_error(parser *yaml_parser_t, directive bool, context_mark yaml_mark_t, problem string) bool { context := "while parsing a tag" if directive { context = "while parsing a %TAG directive" } return yaml_parser_set_scanner_error(parser, context, context_mark, problem) } func trace(args ...interface{}) func() { pargs := append([]interface{}{"+++"}, args...) fmt.Println(pargs...) pargs = append([]interface{}{"---"}, args...) return func() { fmt.Println(pargs...) } } // Ensure that the tokens queue contains at least one token which can be // returned to the Parser. func yaml_parser_fetch_more_tokens(parser *yaml_parser_t) bool { // While we need more tokens to fetch, do it. for { if parser.tokens_head != len(parser.tokens) { // If queue is non-empty, check if any potential simple key may // occupy the head position. head_tok_idx, ok := parser.simple_keys_by_tok[parser.tokens_parsed] if !ok { break } else if valid, ok := yaml_simple_key_is_valid(parser, &parser.simple_keys[head_tok_idx]); !ok { return false } else if !valid { break } } // Fetch the next token. if !yaml_parser_fetch_next_token(parser) { return false } } parser.token_available = true return true } // The dispatcher for token fetchers. func yaml_parser_fetch_next_token(parser *yaml_parser_t) bool { // Ensure that the buffer is initialized. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } // Check if we just started scanning. Fetch STREAM-START then. if !parser.stream_start_produced { return yaml_parser_fetch_stream_start(parser) } // Eat whitespaces and comments until we reach the next token. if !yaml_parser_scan_to_next_token(parser) { return false } // Check the indentation level against the current column. if !yaml_parser_unroll_indent(parser, parser.mark.column) { return false } // Ensure that the buffer contains at least 4 characters. 4 is the length // of the longest indicators ('--- ' and '... '). if parser.unread < 4 && !yaml_parser_update_buffer(parser, 4) { return false } // Is it the end of the stream? if is_z(parser.buffer, parser.buffer_pos) { return yaml_parser_fetch_stream_end(parser) } // Is it a directive? if parser.mark.column == 0 && parser.buffer[parser.buffer_pos] == '%' { return yaml_parser_fetch_directive(parser) } buf := parser.buffer pos := parser.buffer_pos // Is it the document start indicator? if parser.mark.column == 0 && buf[pos] == '-' && buf[pos+1] == '-' && buf[pos+2] == '-' && is_blankz(buf, pos+3) { return yaml_parser_fetch_document_indicator(parser, yaml_DOCUMENT_START_TOKEN) } // Is it the document end indicator? if parser.mark.column == 0 && buf[pos] == '.' && buf[pos+1] == '.' && buf[pos+2] == '.' && is_blankz(buf, pos+3) { return yaml_parser_fetch_document_indicator(parser, yaml_DOCUMENT_END_TOKEN) } // Is it the flow sequence start indicator? if buf[pos] == '[' { return yaml_parser_fetch_flow_collection_start(parser, yaml_FLOW_SEQUENCE_START_TOKEN) } // Is it the flow mapping start indicator? if parser.buffer[parser.buffer_pos] == '{' { return yaml_parser_fetch_flow_collection_start(parser, yaml_FLOW_MAPPING_START_TOKEN) } // Is it the flow sequence end indicator? if parser.buffer[parser.buffer_pos] == ']' { return yaml_parser_fetch_flow_collection_end(parser, yaml_FLOW_SEQUENCE_END_TOKEN) } // Is it the flow mapping end indicator? if parser.buffer[parser.buffer_pos] == '}' { return yaml_parser_fetch_flow_collection_end(parser, yaml_FLOW_MAPPING_END_TOKEN) } // Is it the flow entry indicator? if parser.buffer[parser.buffer_pos] == ',' { return yaml_parser_fetch_flow_entry(parser) } // Is it the block entry indicator? if parser.buffer[parser.buffer_pos] == '-' && is_blankz(parser.buffer, parser.buffer_pos+1) { return yaml_parser_fetch_block_entry(parser) } // Is it the key indicator? if parser.buffer[parser.buffer_pos] == '?' && (parser.flow_level > 0 || is_blankz(parser.buffer, parser.buffer_pos+1)) { return yaml_parser_fetch_key(parser) } // Is it the value indicator? if parser.buffer[parser.buffer_pos] == ':' && (parser.flow_level > 0 || is_blankz(parser.buffer, parser.buffer_pos+1)) { return yaml_parser_fetch_value(parser) } // Is it an alias? if parser.buffer[parser.buffer_pos] == '*' { return yaml_parser_fetch_anchor(parser, yaml_ALIAS_TOKEN) } // Is it an anchor? if parser.buffer[parser.buffer_pos] == '&' { return yaml_parser_fetch_anchor(parser, yaml_ANCHOR_TOKEN) } // Is it a tag? if parser.buffer[parser.buffer_pos] == '!' { return yaml_parser_fetch_tag(parser) } // Is it a literal scalar? if parser.buffer[parser.buffer_pos] == '|' && parser.flow_level == 0 { return yaml_parser_fetch_block_scalar(parser, true) } // Is it a folded scalar? if parser.buffer[parser.buffer_pos] == '>' && parser.flow_level == 0 { return yaml_parser_fetch_block_scalar(parser, false) } // Is it a single-quoted scalar? if parser.buffer[parser.buffer_pos] == '\'' { return yaml_parser_fetch_flow_scalar(parser, true) } // Is it a double-quoted scalar? if parser.buffer[parser.buffer_pos] == '"' { return yaml_parser_fetch_flow_scalar(parser, false) } // Is it a plain scalar? // // A plain scalar may start with any non-blank characters except // // '-', '?', ':', ',', '[', ']', '{', '}', // '#', '&', '*', '!', '|', '>', '\'', '\"', // '%', '@', '`'. // // In the block context (and, for the '-' indicator, in the flow context // too), it may also start with the characters // // '-', '?', ':' // // if it is followed by a non-space character. // // The last rule is more restrictive than the specification requires. // [Go] Make this logic more reasonable. //switch parser.buffer[parser.buffer_pos] { //case '-', '?', ':', ',', '?', '-', ',', ':', ']', '[', '}', '{', '&', '#', '!', '*', '>', '|', '"', '\'', '@', '%', '-', '`': //} if !(is_blankz(parser.buffer, parser.buffer_pos) || parser.buffer[parser.buffer_pos] == '-' || parser.buffer[parser.buffer_pos] == '?' || parser.buffer[parser.buffer_pos] == ':' || parser.buffer[parser.buffer_pos] == ',' || parser.buffer[parser.buffer_pos] == '[' || parser.buffer[parser.buffer_pos] == ']' || parser.buffer[parser.buffer_pos] == '{' || parser.buffer[parser.buffer_pos] == '}' || parser.buffer[parser.buffer_pos] == '#' || parser.buffer[parser.buffer_pos] == '&' || parser.buffer[parser.buffer_pos] == '*' || parser.buffer[parser.buffer_pos] == '!' || parser.buffer[parser.buffer_pos] == '|' || parser.buffer[parser.buffer_pos] == '>' || parser.buffer[parser.buffer_pos] == '\'' || parser.buffer[parser.buffer_pos] == '"' || parser.buffer[parser.buffer_pos] == '%' || parser.buffer[parser.buffer_pos] == '@' || parser.buffer[parser.buffer_pos] == '`') || (parser.buffer[parser.buffer_pos] == '-' && !is_blank(parser.buffer, parser.buffer_pos+1)) || (parser.flow_level == 0 && (parser.buffer[parser.buffer_pos] == '?' || parser.buffer[parser.buffer_pos] == ':') && !is_blankz(parser.buffer, parser.buffer_pos+1)) { return yaml_parser_fetch_plain_scalar(parser) } // If we don't determine the token type so far, it is an error. return yaml_parser_set_scanner_error(parser, "while scanning for the next token", parser.mark, "found character that cannot start any token") } func yaml_simple_key_is_valid(parser *yaml_parser_t, simple_key *yaml_simple_key_t) (valid, ok bool) { if !simple_key.possible { return false, true } // The 1.2 specification says: // // "If the ? indicator is omitted, parsing needs to see past the // implicit key to recognize it as such. To limit the amount of // lookahead required, the “:” indicator must appear at most 1024 // Unicode characters beyond the start of the key. In addition, the key // is restricted to a single line." // if simple_key.mark.line < parser.mark.line || simple_key.mark.index+1024 < parser.mark.index { // Check if the potential simple key to be removed is required. if simple_key.required { return false, yaml_parser_set_scanner_error(parser, "while scanning a simple key", simple_key.mark, "could not find expected ':'") } simple_key.possible = false return false, true } return true, true } // Check if a simple key may start at the current position and add it if // needed. func yaml_parser_save_simple_key(parser *yaml_parser_t) bool { // A simple key is required at the current position if the scanner is in // the block context and the current column coincides with the indentation // level. required := parser.flow_level == 0 && parser.indent == parser.mark.column // // If the current position may start a simple key, save it. // if parser.simple_key_allowed { simple_key := yaml_simple_key_t{ possible: true, required: required, token_number: parser.tokens_parsed + (len(parser.tokens) - parser.tokens_head), mark: parser.mark, } if !yaml_parser_remove_simple_key(parser) { return false } parser.simple_keys[len(parser.simple_keys)-1] = simple_key parser.simple_keys_by_tok[simple_key.token_number] = len(parser.simple_keys) - 1 } return true } // Remove a potential simple key at the current flow level. func yaml_parser_remove_simple_key(parser *yaml_parser_t) bool { i := len(parser.simple_keys) - 1 if parser.simple_keys[i].possible { // If the key is required, it is an error. if parser.simple_keys[i].required { return yaml_parser_set_scanner_error(parser, "while scanning a simple key", parser.simple_keys[i].mark, "could not find expected ':'") } // Remove the key from the stack. parser.simple_keys[i].possible = false delete(parser.simple_keys_by_tok, parser.simple_keys[i].token_number) } return true } // max_flow_level limits the flow_level const max_flow_level = 10000 // Increase the flow level and resize the simple key list if needed. func yaml_parser_increase_flow_level(parser *yaml_parser_t) bool { // Reset the simple key on the next level. parser.simple_keys = append(parser.simple_keys, yaml_simple_key_t{ possible: false, required: false, token_number: parser.tokens_parsed + (len(parser.tokens) - parser.tokens_head), mark: parser.mark, }) // Increase the flow level. parser.flow_level++ if parser.flow_level > max_flow_level { return yaml_parser_set_scanner_error(parser, "while increasing flow level", parser.simple_keys[len(parser.simple_keys)-1].mark, fmt.Sprintf("exceeded max depth of %d", max_flow_level)) } return true } // Decrease the flow level. func yaml_parser_decrease_flow_level(parser *yaml_parser_t) bool { if parser.flow_level > 0 { parser.flow_level-- last := len(parser.simple_keys) - 1 delete(parser.simple_keys_by_tok, parser.simple_keys[last].token_number) parser.simple_keys = parser.simple_keys[:last] } return true } // max_indents limits the indents stack size const max_indents = 10000 // Push the current indentation level to the stack and set the new level // the current column is greater than the indentation level. In this case, // append or insert the specified token into the token queue. func yaml_parser_roll_indent(parser *yaml_parser_t, column, number int, typ yaml_token_type_t, mark yaml_mark_t) bool { // In the flow context, do nothing. if parser.flow_level > 0 { return true } if parser.indent < column { // Push the current indentation level to the stack and set the new // indentation level. parser.indents = append(parser.indents, parser.indent) parser.indent = column if len(parser.indents) > max_indents { return yaml_parser_set_scanner_error(parser, "while increasing indent level", parser.simple_keys[len(parser.simple_keys)-1].mark, fmt.Sprintf("exceeded max depth of %d", max_indents)) } // Create a token and insert it into the queue. token := yaml_token_t{ typ: typ, start_mark: mark, end_mark: mark, } if number > -1 { number -= parser.tokens_parsed } yaml_insert_token(parser, number, &token) } return true } // Pop indentation levels from the indents stack until the current level // becomes less or equal to the column. For each indentation level, append // the BLOCK-END token. func yaml_parser_unroll_indent(parser *yaml_parser_t, column int) bool { // In the flow context, do nothing. if parser.flow_level > 0 { return true } // Loop through the indentation levels in the stack. for parser.indent > column { // Create a token and append it to the queue. token := yaml_token_t{ typ: yaml_BLOCK_END_TOKEN, start_mark: parser.mark, end_mark: parser.mark, } yaml_insert_token(parser, -1, &token) // Pop the indentation level. parser.indent = parser.indents[len(parser.indents)-1] parser.indents = parser.indents[:len(parser.indents)-1] } return true } // Initialize the scanner and produce the STREAM-START token. func yaml_parser_fetch_stream_start(parser *yaml_parser_t) bool { // Set the initial indentation. parser.indent = -1 // Initialize the simple key stack. parser.simple_keys = append(parser.simple_keys, yaml_simple_key_t{}) parser.simple_keys_by_tok = make(map[int]int) // A simple key is allowed at the beginning of the stream. parser.simple_key_allowed = true // We have started. parser.stream_start_produced = true // Create the STREAM-START token and append it to the queue. token := yaml_token_t{ typ: yaml_STREAM_START_TOKEN, start_mark: parser.mark, end_mark: parser.mark, encoding: parser.encoding, } yaml_insert_token(parser, -1, &token) return true } // Produce the STREAM-END token and shut down the scanner. func yaml_parser_fetch_stream_end(parser *yaml_parser_t) bool { // Force new line. if parser.mark.column != 0 { parser.mark.column = 0 parser.mark.line++ } // Reset the indentation level. if !yaml_parser_unroll_indent(parser, -1) { return false } // Reset simple keys. if !yaml_parser_remove_simple_key(parser) { return false } parser.simple_key_allowed = false // Create the STREAM-END token and append it to the queue. token := yaml_token_t{ typ: yaml_STREAM_END_TOKEN, start_mark: parser.mark, end_mark: parser.mark, } yaml_insert_token(parser, -1, &token) return true } // Produce a VERSION-DIRECTIVE or TAG-DIRECTIVE token. func yaml_parser_fetch_directive(parser *yaml_parser_t) bool { // Reset the indentation level. if !yaml_parser_unroll_indent(parser, -1) { return false } // Reset simple keys. if !yaml_parser_remove_simple_key(parser) { return false } parser.simple_key_allowed = false // Create the YAML-DIRECTIVE or TAG-DIRECTIVE token. token := yaml_token_t{} if !yaml_parser_scan_directive(parser, &token) { return false } // Append the token to the queue. yaml_insert_token(parser, -1, &token) return true } // Produce the DOCUMENT-START or DOCUMENT-END token. func yaml_parser_fetch_document_indicator(parser *yaml_parser_t, typ yaml_token_type_t) bool { // Reset the indentation level. if !yaml_parser_unroll_indent(parser, -1) { return false } // Reset simple keys. if !yaml_parser_remove_simple_key(parser) { return false } parser.simple_key_allowed = false // Consume the token. start_mark := parser.mark skip(parser) skip(parser) skip(parser) end_mark := parser.mark // Create the DOCUMENT-START or DOCUMENT-END token. token := yaml_token_t{ typ: typ, start_mark: start_mark, end_mark: end_mark, } // Append the token to the queue. yaml_insert_token(parser, -1, &token) return true } // Produce the FLOW-SEQUENCE-START or FLOW-MAPPING-START token. func yaml_parser_fetch_flow_collection_start(parser *yaml_parser_t, typ yaml_token_type_t) bool { // The indicators '[' and '{' may start a simple key. if !yaml_parser_save_simple_key(parser) { return false } // Increase the flow level. if !yaml_parser_increase_flow_level(parser) { return false } // A simple key may follow the indicators '[' and '{'. parser.simple_key_allowed = true // Consume the token. start_mark := parser.mark skip(parser) end_mark := parser.mark // Create the FLOW-SEQUENCE-START of FLOW-MAPPING-START token. token := yaml_token_t{ typ: typ, start_mark: start_mark, end_mark: end_mark, } // Append the token to the queue. yaml_insert_token(parser, -1, &token) return true } // Produce the FLOW-SEQUENCE-END or FLOW-MAPPING-END token. func yaml_parser_fetch_flow_collection_end(parser *yaml_parser_t, typ yaml_token_type_t) bool { // Reset any potential simple key on the current flow level. if !yaml_parser_remove_simple_key(parser) { return false } // Decrease the flow level. if !yaml_parser_decrease_flow_level(parser) { return false } // No simple keys after the indicators ']' and '}'. parser.simple_key_allowed = false // Consume the token. start_mark := parser.mark skip(parser) end_mark := parser.mark // Create the FLOW-SEQUENCE-END of FLOW-MAPPING-END token. token := yaml_token_t{ typ: typ, start_mark: start_mark, end_mark: end_mark, } // Append the token to the queue. yaml_insert_token(parser, -1, &token) return true } // Produce the FLOW-ENTRY token. func yaml_parser_fetch_flow_entry(parser *yaml_parser_t) bool { // Reset any potential simple keys on the current flow level. if !yaml_parser_remove_simple_key(parser) { return false } // Simple keys are allowed after ','. parser.simple_key_allowed = true // Consume the token. start_mark := parser.mark skip(parser) end_mark := parser.mark // Create the FLOW-ENTRY token and append it to the queue. token := yaml_token_t{ typ: yaml_FLOW_ENTRY_TOKEN, start_mark: start_mark, end_mark: end_mark, } yaml_insert_token(parser, -1, &token) return true } // Produce the BLOCK-ENTRY token. func yaml_parser_fetch_block_entry(parser *yaml_parser_t) bool { // Check if the scanner is in the block context. if parser.flow_level == 0 { // Check if we are allowed to start a new entry. if !parser.simple_key_allowed { return yaml_parser_set_scanner_error(parser, "", parser.mark, "block sequence entries are not allowed in this context") } // Add the BLOCK-SEQUENCE-START token if needed. if !yaml_parser_roll_indent(parser, parser.mark.column, -1, yaml_BLOCK_SEQUENCE_START_TOKEN, parser.mark) { return false } } else { // It is an error for the '-' indicator to occur in the flow context, // but we let the Parser detect and report about it because the Parser // is able to point to the context. } // Reset any potential simple keys on the current flow level. if !yaml_parser_remove_simple_key(parser) { return false } // Simple keys are allowed after '-'. parser.simple_key_allowed = true // Consume the token. start_mark := parser.mark skip(parser) end_mark := parser.mark // Create the BLOCK-ENTRY token and append it to the queue. token := yaml_token_t{ typ: yaml_BLOCK_ENTRY_TOKEN, start_mark: start_mark, end_mark: end_mark, } yaml_insert_token(parser, -1, &token) return true } // Produce the KEY token. func yaml_parser_fetch_key(parser *yaml_parser_t) bool { // In the block context, additional checks are required. if parser.flow_level == 0 { // Check if we are allowed to start a new key (not nessesary simple). if !parser.simple_key_allowed { return yaml_parser_set_scanner_error(parser, "", parser.mark, "mapping keys are not allowed in this context") } // Add the BLOCK-MAPPING-START token if needed. if !yaml_parser_roll_indent(parser, parser.mark.column, -1, yaml_BLOCK_MAPPING_START_TOKEN, parser.mark) { return false } } // Reset any potential simple keys on the current flow level. if !yaml_parser_remove_simple_key(parser) { return false } // Simple keys are allowed after '?' in the block context. parser.simple_key_allowed = parser.flow_level == 0 // Consume the token. start_mark := parser.mark skip(parser) end_mark := parser.mark // Create the KEY token and append it to the queue. token := yaml_token_t{ typ: yaml_KEY_TOKEN, start_mark: start_mark, end_mark: end_mark, } yaml_insert_token(parser, -1, &token) return true } // Produce the VALUE token. func yaml_parser_fetch_value(parser *yaml_parser_t) bool { simple_key := &parser.simple_keys[len(parser.simple_keys)-1] // Have we found a simple key? if valid, ok := yaml_simple_key_is_valid(parser, simple_key); !ok { return false } else if valid { // Create the KEY token and insert it into the queue. token := yaml_token_t{ typ: yaml_KEY_TOKEN, start_mark: simple_key.mark, end_mark: simple_key.mark, } yaml_insert_token(parser, simple_key.token_number-parser.tokens_parsed, &token) // In the block context, we may need to add the BLOCK-MAPPING-START token. if !yaml_parser_roll_indent(parser, simple_key.mark.column, simple_key.token_number, yaml_BLOCK_MAPPING_START_TOKEN, simple_key.mark) { return false } // Remove the simple key. simple_key.possible = false delete(parser.simple_keys_by_tok, simple_key.token_number) // A simple key cannot follow another simple key. parser.simple_key_allowed = false } else { // The ':' indicator follows a complex key. // In the block context, extra checks are required. if parser.flow_level == 0 { // Check if we are allowed to start a complex value. if !parser.simple_key_allowed { return yaml_parser_set_scanner_error(parser, "", parser.mark, "mapping values are not allowed in this context") } // Add the BLOCK-MAPPING-START token if needed. if !yaml_parser_roll_indent(parser, parser.mark.column, -1, yaml_BLOCK_MAPPING_START_TOKEN, parser.mark) { return false } } // Simple keys after ':' are allowed in the block context. parser.simple_key_allowed = parser.flow_level == 0 } // Consume the token. start_mark := parser.mark skip(parser) end_mark := parser.mark // Create the VALUE token and append it to the queue. token := yaml_token_t{ typ: yaml_VALUE_TOKEN, start_mark: start_mark, end_mark: end_mark, } yaml_insert_token(parser, -1, &token) return true } // Produce the ALIAS or ANCHOR token. func yaml_parser_fetch_anchor(parser *yaml_parser_t, typ yaml_token_type_t) bool { // An anchor or an alias could be a simple key. if !yaml_parser_save_simple_key(parser) { return false } // A simple key cannot follow an anchor or an alias. parser.simple_key_allowed = false // Create the ALIAS or ANCHOR token and append it to the queue. var token yaml_token_t if !yaml_parser_scan_anchor(parser, &token, typ) { return false } yaml_insert_token(parser, -1, &token) return true } // Produce the TAG token. func yaml_parser_fetch_tag(parser *yaml_parser_t) bool { // A tag could be a simple key. if !yaml_parser_save_simple_key(parser) { return false } // A simple key cannot follow a tag. parser.simple_key_allowed = false // Create the TAG token and append it to the queue. var token yaml_token_t if !yaml_parser_scan_tag(parser, &token) { return false } yaml_insert_token(parser, -1, &token) return true } // Produce the SCALAR(...,literal) or SCALAR(...,folded) tokens. func yaml_parser_fetch_block_scalar(parser *yaml_parser_t, literal bool) bool { // Remove any potential simple keys. if !yaml_parser_remove_simple_key(parser) { return false } // A simple key may follow a block scalar. parser.simple_key_allowed = true // Create the SCALAR token and append it to the queue. var token yaml_token_t if !yaml_parser_scan_block_scalar(parser, &token, literal) { return false } yaml_insert_token(parser, -1, &token) return true } // Produce the SCALAR(...,single-quoted) or SCALAR(...,double-quoted) tokens. func yaml_parser_fetch_flow_scalar(parser *yaml_parser_t, single bool) bool { // A plain scalar could be a simple key. if !yaml_parser_save_simple_key(parser) { return false } // A simple key cannot follow a flow scalar. parser.simple_key_allowed = false // Create the SCALAR token and append it to the queue. var token yaml_token_t if !yaml_parser_scan_flow_scalar(parser, &token, single) { return false } yaml_insert_token(parser, -1, &token) return true } // Produce the SCALAR(...,plain) token. func yaml_parser_fetch_plain_scalar(parser *yaml_parser_t) bool { // A plain scalar could be a simple key. if !yaml_parser_save_simple_key(parser) { return false } // A simple key cannot follow a flow scalar. parser.simple_key_allowed = false // Create the SCALAR token and append it to the queue. var token yaml_token_t if !yaml_parser_scan_plain_scalar(parser, &token) { return false } yaml_insert_token(parser, -1, &token) return true } // Eat whitespaces and comments until the next token is found. func yaml_parser_scan_to_next_token(parser *yaml_parser_t) bool { // Until the next token is not found. for { // Allow the BOM mark to start a line. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } if parser.mark.column == 0 && is_bom(parser.buffer, parser.buffer_pos) { skip(parser) } // Eat whitespaces. // Tabs are allowed: // - in the flow context // - in the block context, but not at the beginning of the line or // after '-', '?', or ':' (complex value). if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } for parser.buffer[parser.buffer_pos] == ' ' || ((parser.flow_level > 0 || !parser.simple_key_allowed) && parser.buffer[parser.buffer_pos] == '\t') { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Eat a comment until a line break. if parser.buffer[parser.buffer_pos] == '#' { for !is_breakz(parser.buffer, parser.buffer_pos) { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } } // If it is a line break, eat it. if is_break(parser.buffer, parser.buffer_pos) { if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } skip_line(parser) // In the block context, a new line may start a simple key. if parser.flow_level == 0 { parser.simple_key_allowed = true } } else { break // We have found a token. } } return true } // Scan a YAML-DIRECTIVE or TAG-DIRECTIVE token. // // Scope: // %YAML 1.1 # a comment \n // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ // %TAG !yaml! tag:yaml.org,2002: \n // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ // func yaml_parser_scan_directive(parser *yaml_parser_t, token *yaml_token_t) bool { // Eat '%'. start_mark := parser.mark skip(parser) // Scan the directive name. var name []byte if !yaml_parser_scan_directive_name(parser, start_mark, &name) { return false } // Is it a YAML directive? if bytes.Equal(name, []byte("YAML")) { // Scan the VERSION directive value. var major, minor int8 if !yaml_parser_scan_version_directive_value(parser, start_mark, &major, &minor) { return false } end_mark := parser.mark // Create a VERSION-DIRECTIVE token. *token = yaml_token_t{ typ: yaml_VERSION_DIRECTIVE_TOKEN, start_mark: start_mark, end_mark: end_mark, major: major, minor: minor, } // Is it a TAG directive? } else if bytes.Equal(name, []byte("TAG")) { // Scan the TAG directive value. var handle, prefix []byte if !yaml_parser_scan_tag_directive_value(parser, start_mark, &handle, &prefix) { return false } end_mark := parser.mark // Create a TAG-DIRECTIVE token. *token = yaml_token_t{ typ: yaml_TAG_DIRECTIVE_TOKEN, start_mark: start_mark, end_mark: end_mark, value: handle, prefix: prefix, } // Unknown directive. } else { yaml_parser_set_scanner_error(parser, "while scanning a directive", start_mark, "found unknown directive name") return false } // Eat the rest of the line including any comments. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } for is_blank(parser.buffer, parser.buffer_pos) { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } if parser.buffer[parser.buffer_pos] == '#' { for !is_breakz(parser.buffer, parser.buffer_pos) { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } } // Check if we are at the end of the line. if !is_breakz(parser.buffer, parser.buffer_pos) { yaml_parser_set_scanner_error(parser, "while scanning a directive", start_mark, "did not find expected comment or line break") return false } // Eat a line break. if is_break(parser.buffer, parser.buffer_pos) { if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } skip_line(parser) } return true } // Scan the directive name. // // Scope: // %YAML 1.1 # a comment \n // ^^^^ // %TAG !yaml! tag:yaml.org,2002: \n // ^^^ // func yaml_parser_scan_directive_name(parser *yaml_parser_t, start_mark yaml_mark_t, name *[]byte) bool { // Consume the directive name. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } var s []byte for is_alpha(parser.buffer, parser.buffer_pos) { s = read(parser, s) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Check if the name is empty. if len(s) == 0 { yaml_parser_set_scanner_error(parser, "while scanning a directive", start_mark, "could not find expected directive name") return false } // Check for an blank character after the name. if !is_blankz(parser.buffer, parser.buffer_pos) { yaml_parser_set_scanner_error(parser, "while scanning a directive", start_mark, "found unexpected non-alphabetical character") return false } *name = s return true } // Scan the value of VERSION-DIRECTIVE. // // Scope: // %YAML 1.1 # a comment \n // ^^^^^^ func yaml_parser_scan_version_directive_value(parser *yaml_parser_t, start_mark yaml_mark_t, major, minor *int8) bool { // Eat whitespaces. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } for is_blank(parser.buffer, parser.buffer_pos) { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Consume the major version number. if !yaml_parser_scan_version_directive_number(parser, start_mark, major) { return false } // Eat '.'. if parser.buffer[parser.buffer_pos] != '.' { return yaml_parser_set_scanner_error(parser, "while scanning a %YAML directive", start_mark, "did not find expected digit or '.' character") } skip(parser) // Consume the minor version number. if !yaml_parser_scan_version_directive_number(parser, start_mark, minor) { return false } return true } const max_number_length = 2 // Scan the version number of VERSION-DIRECTIVE. // // Scope: // %YAML 1.1 # a comment \n // ^ // %YAML 1.1 # a comment \n // ^ func yaml_parser_scan_version_directive_number(parser *yaml_parser_t, start_mark yaml_mark_t, number *int8) bool { // Repeat while the next character is digit. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } var value, length int8 for is_digit(parser.buffer, parser.buffer_pos) { // Check if the number is too long. length++ if length > max_number_length { return yaml_parser_set_scanner_error(parser, "while scanning a %YAML directive", start_mark, "found extremely long version number") } value = value*10 + int8(as_digit(parser.buffer, parser.buffer_pos)) skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Check if the number was present. if length == 0 { return yaml_parser_set_scanner_error(parser, "while scanning a %YAML directive", start_mark, "did not find expected version number") } *number = value return true } // Scan the value of a TAG-DIRECTIVE token. // // Scope: // %TAG !yaml! tag:yaml.org,2002: \n // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ // func yaml_parser_scan_tag_directive_value(parser *yaml_parser_t, start_mark yaml_mark_t, handle, prefix *[]byte) bool { var handle_value, prefix_value []byte // Eat whitespaces. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } for is_blank(parser.buffer, parser.buffer_pos) { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Scan a handle. if !yaml_parser_scan_tag_handle(parser, true, start_mark, &handle_value) { return false } // Expect a whitespace. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } if !is_blank(parser.buffer, parser.buffer_pos) { yaml_parser_set_scanner_error(parser, "while scanning a %TAG directive", start_mark, "did not find expected whitespace") return false } // Eat whitespaces. for is_blank(parser.buffer, parser.buffer_pos) { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Scan a prefix. if !yaml_parser_scan_tag_uri(parser, true, nil, start_mark, &prefix_value) { return false } // Expect a whitespace or line break. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } if !is_blankz(parser.buffer, parser.buffer_pos) { yaml_parser_set_scanner_error(parser, "while scanning a %TAG directive", start_mark, "did not find expected whitespace or line break") return false } *handle = handle_value *prefix = prefix_value return true } func yaml_parser_scan_anchor(parser *yaml_parser_t, token *yaml_token_t, typ yaml_token_type_t) bool { var s []byte // Eat the indicator character. start_mark := parser.mark skip(parser) // Consume the value. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } for is_alpha(parser.buffer, parser.buffer_pos) { s = read(parser, s) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } end_mark := parser.mark /* * Check if length of the anchor is greater than 0 and it is followed by * a whitespace character or one of the indicators: * * '?', ':', ',', ']', '}', '%', '@', '`'. */ if len(s) == 0 || !(is_blankz(parser.buffer, parser.buffer_pos) || parser.buffer[parser.buffer_pos] == '?' || parser.buffer[parser.buffer_pos] == ':' || parser.buffer[parser.buffer_pos] == ',' || parser.buffer[parser.buffer_pos] == ']' || parser.buffer[parser.buffer_pos] == '}' || parser.buffer[parser.buffer_pos] == '%' || parser.buffer[parser.buffer_pos] == '@' || parser.buffer[parser.buffer_pos] == '`') { context := "while scanning an alias" if typ == yaml_ANCHOR_TOKEN { context = "while scanning an anchor" } yaml_parser_set_scanner_error(parser, context, start_mark, "did not find expected alphabetic or numeric character") return false } // Create a token. *token = yaml_token_t{ typ: typ, start_mark: start_mark, end_mark: end_mark, value: s, } return true } /* * Scan a TAG token. */ func yaml_parser_scan_tag(parser *yaml_parser_t, token *yaml_token_t) bool { var handle, suffix []byte start_mark := parser.mark // Check if the tag is in the canonical form. if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } if parser.buffer[parser.buffer_pos+1] == '<' { // Keep the handle as '' // Eat '!<' skip(parser) skip(parser) // Consume the tag value. if !yaml_parser_scan_tag_uri(parser, false, nil, start_mark, &suffix) { return false } // Check for '>' and eat it. if parser.buffer[parser.buffer_pos] != '>' { yaml_parser_set_scanner_error(parser, "while scanning a tag", start_mark, "did not find the expected '>'") return false } skip(parser) } else { // The tag has either the '!suffix' or the '!handle!suffix' form. // First, try to scan a handle. if !yaml_parser_scan_tag_handle(parser, false, start_mark, &handle) { return false } // Check if it is, indeed, handle. if handle[0] == '!' && len(handle) > 1 && handle[len(handle)-1] == '!' { // Scan the suffix now. if !yaml_parser_scan_tag_uri(parser, false, nil, start_mark, &suffix) { return false } } else { // It wasn't a handle after all. Scan the rest of the tag. if !yaml_parser_scan_tag_uri(parser, false, handle, start_mark, &suffix) { return false } // Set the handle to '!'. handle = []byte{'!'} // A special case: the '!' tag. Set the handle to '' and the // suffix to '!'. if len(suffix) == 0 { handle, suffix = suffix, handle } } } // Check the character which ends the tag. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } if !is_blankz(parser.buffer, parser.buffer_pos) { yaml_parser_set_scanner_error(parser, "while scanning a tag", start_mark, "did not find expected whitespace or line break") return false } end_mark := parser.mark // Create a token. *token = yaml_token_t{ typ: yaml_TAG_TOKEN, start_mark: start_mark, end_mark: end_mark, value: handle, suffix: suffix, } return true } // Scan a tag handle. func yaml_parser_scan_tag_handle(parser *yaml_parser_t, directive bool, start_mark yaml_mark_t, handle *[]byte) bool { // Check the initial '!' character. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } if parser.buffer[parser.buffer_pos] != '!' { yaml_parser_set_scanner_tag_error(parser, directive, start_mark, "did not find expected '!'") return false } var s []byte // Copy the '!' character. s = read(parser, s) // Copy all subsequent alphabetical and numerical characters. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } for is_alpha(parser.buffer, parser.buffer_pos) { s = read(parser, s) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Check if the trailing character is '!' and copy it. if parser.buffer[parser.buffer_pos] == '!' { s = read(parser, s) } else { // It's either the '!' tag or not really a tag handle. If it's a %TAG // directive, it's an error. If it's a tag token, it must be a part of URI. if directive && string(s) != "!" { yaml_parser_set_scanner_tag_error(parser, directive, start_mark, "did not find expected '!'") return false } } *handle = s return true } // Scan a tag. func yaml_parser_scan_tag_uri(parser *yaml_parser_t, directive bool, head []byte, start_mark yaml_mark_t, uri *[]byte) bool { //size_t length = head ? strlen((char *)head) : 0 var s []byte hasTag := len(head) > 0 // Copy the head if needed. // // Note that we don't copy the leading '!' character. if len(head) > 1 { s = append(s, head[1:]...) } // Scan the tag. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } // The set of characters that may appear in URI is as follows: // // '0'-'9', 'A'-'Z', 'a'-'z', '_', '-', ';', '/', '?', ':', '@', '&', // '=', '+', '$', ',', '.', '!', '~', '*', '\'', '(', ')', '[', ']', // '%'. // [Go] Convert this into more reasonable logic. for is_alpha(parser.buffer, parser.buffer_pos) || parser.buffer[parser.buffer_pos] == ';' || parser.buffer[parser.buffer_pos] == '/' || parser.buffer[parser.buffer_pos] == '?' || parser.buffer[parser.buffer_pos] == ':' || parser.buffer[parser.buffer_pos] == '@' || parser.buffer[parser.buffer_pos] == '&' || parser.buffer[parser.buffer_pos] == '=' || parser.buffer[parser.buffer_pos] == '+' || parser.buffer[parser.buffer_pos] == '$' || parser.buffer[parser.buffer_pos] == ',' || parser.buffer[parser.buffer_pos] == '.' || parser.buffer[parser.buffer_pos] == '!' || parser.buffer[parser.buffer_pos] == '~' || parser.buffer[parser.buffer_pos] == '*' || parser.buffer[parser.buffer_pos] == '\'' || parser.buffer[parser.buffer_pos] == '(' || parser.buffer[parser.buffer_pos] == ')' || parser.buffer[parser.buffer_pos] == '[' || parser.buffer[parser.buffer_pos] == ']' || parser.buffer[parser.buffer_pos] == '%' { // Check if it is a URI-escape sequence. if parser.buffer[parser.buffer_pos] == '%' { if !yaml_parser_scan_uri_escapes(parser, directive, start_mark, &s) { return false } } else { s = read(parser, s) } if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } hasTag = true } if !hasTag { yaml_parser_set_scanner_tag_error(parser, directive, start_mark, "did not find expected tag URI") return false } *uri = s return true } // Decode an URI-escape sequence corresponding to a single UTF-8 character. func yaml_parser_scan_uri_escapes(parser *yaml_parser_t, directive bool, start_mark yaml_mark_t, s *[]byte) bool { // Decode the required number of characters. w := 1024 for w > 0 { // Check for a URI-escaped octet. if parser.unread < 3 && !yaml_parser_update_buffer(parser, 3) { return false } if !(parser.buffer[parser.buffer_pos] == '%' && is_hex(parser.buffer, parser.buffer_pos+1) && is_hex(parser.buffer, parser.buffer_pos+2)) { return yaml_parser_set_scanner_tag_error(parser, directive, start_mark, "did not find URI escaped octet") } // Get the octet. octet := byte((as_hex(parser.buffer, parser.buffer_pos+1) << 4) + as_hex(parser.buffer, parser.buffer_pos+2)) // If it is the leading octet, determine the length of the UTF-8 sequence. if w == 1024 { w = width(octet) if w == 0 { return yaml_parser_set_scanner_tag_error(parser, directive, start_mark, "found an incorrect leading UTF-8 octet") } } else { // Check if the trailing octet is correct. if octet&0xC0 != 0x80 { return yaml_parser_set_scanner_tag_error(parser, directive, start_mark, "found an incorrect trailing UTF-8 octet") } } // Copy the octet and move the pointers. *s = append(*s, octet) skip(parser) skip(parser) skip(parser) w-- } return true } // Scan a block scalar. func yaml_parser_scan_block_scalar(parser *yaml_parser_t, token *yaml_token_t, literal bool) bool { // Eat the indicator '|' or '>'. start_mark := parser.mark skip(parser) // Scan the additional block scalar indicators. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } // Check for a chomping indicator. var chomping, increment int if parser.buffer[parser.buffer_pos] == '+' || parser.buffer[parser.buffer_pos] == '-' { // Set the chomping method and eat the indicator. if parser.buffer[parser.buffer_pos] == '+' { chomping = +1 } else { chomping = -1 } skip(parser) // Check for an indentation indicator. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } if is_digit(parser.buffer, parser.buffer_pos) { // Check that the indentation is greater than 0. if parser.buffer[parser.buffer_pos] == '0' { yaml_parser_set_scanner_error(parser, "while scanning a block scalar", start_mark, "found an indentation indicator equal to 0") return false } // Get the indentation level and eat the indicator. increment = as_digit(parser.buffer, parser.buffer_pos) skip(parser) } } else if is_digit(parser.buffer, parser.buffer_pos) { // Do the same as above, but in the opposite order. if parser.buffer[parser.buffer_pos] == '0' { yaml_parser_set_scanner_error(parser, "while scanning a block scalar", start_mark, "found an indentation indicator equal to 0") return false } increment = as_digit(parser.buffer, parser.buffer_pos) skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } if parser.buffer[parser.buffer_pos] == '+' || parser.buffer[parser.buffer_pos] == '-' { if parser.buffer[parser.buffer_pos] == '+' { chomping = +1 } else { chomping = -1 } skip(parser) } } // Eat whitespaces and comments to the end of the line. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } for is_blank(parser.buffer, parser.buffer_pos) { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } if parser.buffer[parser.buffer_pos] == '#' { for !is_breakz(parser.buffer, parser.buffer_pos) { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } } // Check if we are at the end of the line. if !is_breakz(parser.buffer, parser.buffer_pos) { yaml_parser_set_scanner_error(parser, "while scanning a block scalar", start_mark, "did not find expected comment or line break") return false } // Eat a line break. if is_break(parser.buffer, parser.buffer_pos) { if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } skip_line(parser) } end_mark := parser.mark // Set the indentation level if it was specified. var indent int if increment > 0 { if parser.indent >= 0 { indent = parser.indent + increment } else { indent = increment } } // Scan the leading line breaks and determine the indentation level if needed. var s, leading_break, trailing_breaks []byte if !yaml_parser_scan_block_scalar_breaks(parser, &indent, &trailing_breaks, start_mark, &end_mark) { return false } // Scan the block scalar content. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } var leading_blank, trailing_blank bool for parser.mark.column == indent && !is_z(parser.buffer, parser.buffer_pos) { // We are at the beginning of a non-empty line. // Is it a trailing whitespace? trailing_blank = is_blank(parser.buffer, parser.buffer_pos) // Check if we need to fold the leading line break. if !literal && !leading_blank && !trailing_blank && len(leading_break) > 0 && leading_break[0] == '\n' { // Do we need to join the lines by space? if len(trailing_breaks) == 0 { s = append(s, ' ') } } else { s = append(s, leading_break...) } leading_break = leading_break[:0] // Append the remaining line breaks. s = append(s, trailing_breaks...) trailing_breaks = trailing_breaks[:0] // Is it a leading whitespace? leading_blank = is_blank(parser.buffer, parser.buffer_pos) // Consume the current line. for !is_breakz(parser.buffer, parser.buffer_pos) { s = read(parser, s) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Consume the line break. if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } leading_break = read_line(parser, leading_break) // Eat the following indentation spaces and line breaks. if !yaml_parser_scan_block_scalar_breaks(parser, &indent, &trailing_breaks, start_mark, &end_mark) { return false } } // Chomp the tail. if chomping != -1 { s = append(s, leading_break...) } if chomping == 1 { s = append(s, trailing_breaks...) } // Create a token. *token = yaml_token_t{ typ: yaml_SCALAR_TOKEN, start_mark: start_mark, end_mark: end_mark, value: s, style: yaml_LITERAL_SCALAR_STYLE, } if !literal { token.style = yaml_FOLDED_SCALAR_STYLE } return true } // Scan indentation spaces and line breaks for a block scalar. Determine the // indentation level if needed. func yaml_parser_scan_block_scalar_breaks(parser *yaml_parser_t, indent *int, breaks *[]byte, start_mark yaml_mark_t, end_mark *yaml_mark_t) bool { *end_mark = parser.mark // Eat the indentation spaces and line breaks. max_indent := 0 for { // Eat the indentation spaces. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } for (*indent == 0 || parser.mark.column < *indent) && is_space(parser.buffer, parser.buffer_pos) { skip(parser) if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } if parser.mark.column > max_indent { max_indent = parser.mark.column } // Check for a tab character messing the indentation. if (*indent == 0 || parser.mark.column < *indent) && is_tab(parser.buffer, parser.buffer_pos) { return yaml_parser_set_scanner_error(parser, "while scanning a block scalar", start_mark, "found a tab character where an indentation space is expected") } // Have we found a non-empty line? if !is_break(parser.buffer, parser.buffer_pos) { break } // Consume the line break. if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } // [Go] Should really be returning breaks instead. *breaks = read_line(parser, *breaks) *end_mark = parser.mark } // Determine the indentation level if needed. if *indent == 0 { *indent = max_indent if *indent < parser.indent+1 { *indent = parser.indent + 1 } if *indent < 1 { *indent = 1 } } return true } // Scan a quoted scalar. func yaml_parser_scan_flow_scalar(parser *yaml_parser_t, token *yaml_token_t, single bool) bool { // Eat the left quote. start_mark := parser.mark skip(parser) // Consume the content of the quoted scalar. var s, leading_break, trailing_breaks, whitespaces []byte for { // Check that there are no document indicators at the beginning of the line. if parser.unread < 4 && !yaml_parser_update_buffer(parser, 4) { return false } if parser.mark.column == 0 && ((parser.buffer[parser.buffer_pos+0] == '-' && parser.buffer[parser.buffer_pos+1] == '-' && parser.buffer[parser.buffer_pos+2] == '-') || (parser.buffer[parser.buffer_pos+0] == '.' && parser.buffer[parser.buffer_pos+1] == '.' && parser.buffer[parser.buffer_pos+2] == '.')) && is_blankz(parser.buffer, parser.buffer_pos+3) { yaml_parser_set_scanner_error(parser, "while scanning a quoted scalar", start_mark, "found unexpected document indicator") return false } // Check for EOF. if is_z(parser.buffer, parser.buffer_pos) { yaml_parser_set_scanner_error(parser, "while scanning a quoted scalar", start_mark, "found unexpected end of stream") return false } // Consume non-blank characters. leading_blanks := false for !is_blankz(parser.buffer, parser.buffer_pos) { if single && parser.buffer[parser.buffer_pos] == '\'' && parser.buffer[parser.buffer_pos+1] == '\'' { // Is is an escaped single quote. s = append(s, '\'') skip(parser) skip(parser) } else if single && parser.buffer[parser.buffer_pos] == '\'' { // It is a right single quote. break } else if !single && parser.buffer[parser.buffer_pos] == '"' { // It is a right double quote. break } else if !single && parser.buffer[parser.buffer_pos] == '\\' && is_break(parser.buffer, parser.buffer_pos+1) { // It is an escaped line break. if parser.unread < 3 && !yaml_parser_update_buffer(parser, 3) { return false } skip(parser) skip_line(parser) leading_blanks = true break } else if !single && parser.buffer[parser.buffer_pos] == '\\' { // It is an escape sequence. code_length := 0 // Check the escape character. switch parser.buffer[parser.buffer_pos+1] { case '0': s = append(s, 0) case 'a': s = append(s, '\x07') case 'b': s = append(s, '\x08') case 't', '\t': s = append(s, '\x09') case 'n': s = append(s, '\x0A') case 'v': s = append(s, '\x0B') case 'f': s = append(s, '\x0C') case 'r': s = append(s, '\x0D') case 'e': s = append(s, '\x1B') case ' ': s = append(s, '\x20') case '"': s = append(s, '"') case '\'': s = append(s, '\'') case '\\': s = append(s, '\\') case 'N': // NEL (#x85) s = append(s, '\xC2') s = append(s, '\x85') case '_': // #xA0 s = append(s, '\xC2') s = append(s, '\xA0') case 'L': // LS (#x2028) s = append(s, '\xE2') s = append(s, '\x80') s = append(s, '\xA8') case 'P': // PS (#x2029) s = append(s, '\xE2') s = append(s, '\x80') s = append(s, '\xA9') case 'x': code_length = 2 case 'u': code_length = 4 case 'U': code_length = 8 default: yaml_parser_set_scanner_error(parser, "while parsing a quoted scalar", start_mark, "found unknown escape character") return false } skip(parser) skip(parser) // Consume an arbitrary escape code. if code_length > 0 { var value int // Scan the character value. if parser.unread < code_length && !yaml_parser_update_buffer(parser, code_length) { return false } for k := 0; k < code_length; k++ { if !is_hex(parser.buffer, parser.buffer_pos+k) { yaml_parser_set_scanner_error(parser, "while parsing a quoted scalar", start_mark, "did not find expected hexdecimal number") return false } value = (value << 4) + as_hex(parser.buffer, parser.buffer_pos+k) } // Check the value and write the character. if (value >= 0xD800 && value <= 0xDFFF) || value > 0x10FFFF { yaml_parser_set_scanner_error(parser, "while parsing a quoted scalar", start_mark, "found invalid Unicode character escape code") return false } if value <= 0x7F { s = append(s, byte(value)) } else if value <= 0x7FF { s = append(s, byte(0xC0+(value>>6))) s = append(s, byte(0x80+(value&0x3F))) } else if value <= 0xFFFF { s = append(s, byte(0xE0+(value>>12))) s = append(s, byte(0x80+((value>>6)&0x3F))) s = append(s, byte(0x80+(value&0x3F))) } else { s = append(s, byte(0xF0+(value>>18))) s = append(s, byte(0x80+((value>>12)&0x3F))) s = append(s, byte(0x80+((value>>6)&0x3F))) s = append(s, byte(0x80+(value&0x3F))) } // Advance the pointer. for k := 0; k < code_length; k++ { skip(parser) } } } else { // It is a non-escaped non-blank character. s = read(parser, s) } if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } } if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } // Check if we are at the end of the scalar. if single { if parser.buffer[parser.buffer_pos] == '\'' { break } } else { if parser.buffer[parser.buffer_pos] == '"' { break } } // Consume blank characters. for is_blank(parser.buffer, parser.buffer_pos) || is_break(parser.buffer, parser.buffer_pos) { if is_blank(parser.buffer, parser.buffer_pos) { // Consume a space or a tab character. if !leading_blanks { whitespaces = read(parser, whitespaces) } else { skip(parser) } } else { if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } // Check if it is a first line break. if !leading_blanks { whitespaces = whitespaces[:0] leading_break = read_line(parser, leading_break) leading_blanks = true } else { trailing_breaks = read_line(parser, trailing_breaks) } } if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Join the whitespaces or fold line breaks. if leading_blanks { // Do we need to fold line breaks? if len(leading_break) > 0 && leading_break[0] == '\n' { if len(trailing_breaks) == 0 { s = append(s, ' ') } else { s = append(s, trailing_breaks...) } } else { s = append(s, leading_break...) s = append(s, trailing_breaks...) } trailing_breaks = trailing_breaks[:0] leading_break = leading_break[:0] } else { s = append(s, whitespaces...) whitespaces = whitespaces[:0] } } // Eat the right quote. skip(parser) end_mark := parser.mark // Create a token. *token = yaml_token_t{ typ: yaml_SCALAR_TOKEN, start_mark: start_mark, end_mark: end_mark, value: s, style: yaml_SINGLE_QUOTED_SCALAR_STYLE, } if !single { token.style = yaml_DOUBLE_QUOTED_SCALAR_STYLE } return true } // Scan a plain scalar. func yaml_parser_scan_plain_scalar(parser *yaml_parser_t, token *yaml_token_t) bool { var s, leading_break, trailing_breaks, whitespaces []byte var leading_blanks bool var indent = parser.indent + 1 start_mark := parser.mark end_mark := parser.mark // Consume the content of the plain scalar. for { // Check for a document indicator. if parser.unread < 4 && !yaml_parser_update_buffer(parser, 4) { return false } if parser.mark.column == 0 && ((parser.buffer[parser.buffer_pos+0] == '-' && parser.buffer[parser.buffer_pos+1] == '-' && parser.buffer[parser.buffer_pos+2] == '-') || (parser.buffer[parser.buffer_pos+0] == '.' && parser.buffer[parser.buffer_pos+1] == '.' && parser.buffer[parser.buffer_pos+2] == '.')) && is_blankz(parser.buffer, parser.buffer_pos+3) { break } // Check for a comment. if parser.buffer[parser.buffer_pos] == '#' { break } // Consume non-blank characters. for !is_blankz(parser.buffer, parser.buffer_pos) { // Check for indicators that may end a plain scalar. if (parser.buffer[parser.buffer_pos] == ':' && is_blankz(parser.buffer, parser.buffer_pos+1)) || (parser.flow_level > 0 && (parser.buffer[parser.buffer_pos] == ',' || parser.buffer[parser.buffer_pos] == '?' || parser.buffer[parser.buffer_pos] == '[' || parser.buffer[parser.buffer_pos] == ']' || parser.buffer[parser.buffer_pos] == '{' || parser.buffer[parser.buffer_pos] == '}')) { break } // Check if we need to join whitespaces and breaks. if leading_blanks || len(whitespaces) > 0 { if leading_blanks { // Do we need to fold line breaks? if leading_break[0] == '\n' { if len(trailing_breaks) == 0 { s = append(s, ' ') } else { s = append(s, trailing_breaks...) } } else { s = append(s, leading_break...) s = append(s, trailing_breaks...) } trailing_breaks = trailing_breaks[:0] leading_break = leading_break[:0] leading_blanks = false } else { s = append(s, whitespaces...) whitespaces = whitespaces[:0] } } // Copy the character. s = read(parser, s) end_mark = parser.mark if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } } // Is it the end? if !(is_blank(parser.buffer, parser.buffer_pos) || is_break(parser.buffer, parser.buffer_pos)) { break } // Consume blank characters. if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } for is_blank(parser.buffer, parser.buffer_pos) || is_break(parser.buffer, parser.buffer_pos) { if is_blank(parser.buffer, parser.buffer_pos) { // Check for tab characters that abuse indentation. if leading_blanks && parser.mark.column < indent && is_tab(parser.buffer, parser.buffer_pos) { yaml_parser_set_scanner_error(parser, "while scanning a plain scalar", start_mark, "found a tab character that violates indentation") return false } // Consume a space or a tab character. if !leading_blanks { whitespaces = read(parser, whitespaces) } else { skip(parser) } } else { if parser.unread < 2 && !yaml_parser_update_buffer(parser, 2) { return false } // Check if it is a first line break. if !leading_blanks { whitespaces = whitespaces[:0] leading_break = read_line(parser, leading_break) leading_blanks = true } else { trailing_breaks = read_line(parser, trailing_breaks) } } if parser.unread < 1 && !yaml_parser_update_buffer(parser, 1) { return false } } // Check indentation level. if parser.flow_level == 0 && parser.mark.column < indent { break } } // Create a token. *token = yaml_token_t{ typ: yaml_SCALAR_TOKEN, start_mark: start_mark, end_mark: end_mark, value: s, style: yaml_PLAIN_SCALAR_STYLE, } // Note that we change the 'simple_key_allowed' flag. if leading_blanks { parser.simple_key_allowed = true } return true }