#ifndef PKTLINE_H

#define PKTLINE_H

#include "git-compat-util.h"

#include "strbuf.h"

/*

 * Write a packetized stream, where each line is preceded by

 * its length (including the header) as a 4-byte hex number.

 * A length of 'zero' means end of stream (and a length of 1-3

 * would be an error).

 *

 * This is all pretty stupid, but we use this packetized line

 * format to make a streaming format possible without ever

 * over-running the read buffers. That way we'll never read

 * into what might be the pack data (which should go to another

 * process entirely).

 *

 * The writing side could use stdio, but since the reading

 * side can't, we stay with pure read/write interfaces.

 */

void packet_flush(int fd);

void packet_delim(int fd);

void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));

void packet_buf_flush(struct strbuf *buf);

void packet_buf_delim(struct strbuf *buf);

void packet_write(int fd_out, const char *buf, size_t size);

void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));

void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len);

int packet_flush_gently(int fd);

int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));

int write_packetized_from_fd(int fd_in, int fd_out);

int write_packetized_from_buf(const char *src_in, size_t len, int fd_out);

/*

 * Read a packetized line into the buffer, which must be at least size bytes

 * long. The return value specifies the number of bytes read into the buffer.

 *

 * If src_buffer and *src_buffer are not NULL, it should point to a buffer

 * containing the packet data to parse, of at least *src_len bytes.  After the

 * function returns, src_buf will be incremented and src_len decremented by the

 * number of bytes consumed.

 *

 * If src_buffer (or *src_buffer) is NULL, then data is read from the

 * descriptor "fd".

 *

 * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any

 * of the following conditions:

 *

 *   1. Read error from descriptor.

 *

 *   2. Protocol error from the remote (e.g., bogus length characters).

 *

 *   3. Receiving a packet larger than "size" bytes.

 *

 *   4. Truncated output from the remote (e.g., we expected a packet but got

 *      EOF, or we got a partial packet followed by EOF).

 *

 * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on

 * condition 4 (truncated input), but instead return -1. However, we will still

 * die for the other 3 conditions.

 *

 * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if

 * present) is removed from the buffer before returning.

 */

#define PACKET_READ_GENTLE_ON_EOF (1u<<0)

#define PACKET_READ_CHOMP_NEWLINE (1u<<1)

int packet_read(int fd, char **src_buffer, size_t *src_len, char

		*buffer, unsigned size, int options);

/*

 * Read a packetized line into a buffer like the 'packet_read()' function but

 * returns an 'enum packet_read_status' which indicates the status of the read.

 * The number of bytes read will be assigined to *pktlen if the status of the

 * read was 'PACKET_READ_NORMAL'.

 */

enum packet_read_status {

	PACKET_READ_EOF,

	PACKET_READ_NORMAL,

	PACKET_READ_FLUSH,

	PACKET_READ_DELIM,

};

enum packet_read_status packet_read_with_status(int fd, char **src_buffer,

						size_t *src_len, char *buffer,

						unsigned size, int *pktlen,

						int options);

/*

 * Convenience wrapper for packet_read that is not gentle, and sets the

 * CHOMP_NEWLINE option. The return value is NULL for a flush packet,

 * and otherwise points to a static buffer (that may be overwritten by

 * subsequent calls). If the size parameter is not NULL, the length of the

 * packet is written to it.

 */

char *packet_read_line(int fd, int *size);

/*

 * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF

 * and CHOMP_NEWLINE options. The return value specifies the number of bytes

 * read into the buffer or -1 on truncated input. If the *dst_line parameter

 * is not NULL it will return NULL for a flush packet or when the number of

 * bytes copied is zero and otherwise points to a static buffer (that may be

 * overwritten by subsequent calls). If the size parameter is not NULL, the

 * length of the packet is written to it.

 */

int packet_read_line_gently(int fd, int *size, char **dst_line);

/*

 * Same as packet_read_line, but read from a buf rather than a descriptor;

 * see packet_read for details on how src_* is used.

 */

char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);

/*

 * Reads a stream of variable sized packets until a flush packet is detected.

 */

ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out);

struct packet_reader {

	/* source file descriptor */

	int fd;

	/* source buffer and its size */

	char *src_buffer;

	size_t src_len;

	/* buffer that pkt-lines are read into and its size */

	char *buffer;

	unsigned buffer_size;

	/* options to be used during reads */

	int options;

	/* status of the last read */

	enum packet_read_status status;

	/* length of data read during the last read */

	int pktlen;

	/* the last line read */

	const char *line;

	/* indicates if a line has been peeked */

	int line_peeked;

};

/*

 * Initialize a 'struct packet_reader' object which is an

 * abstraction around the 'packet_read_with_status()' function.

 */

extern void packet_reader_init(struct packet_reader *reader, int fd,

			       char *src_buffer, size_t src_len,

			       int options);

/*

 * Perform a packet read and return the status of the read.

 * The values of 'pktlen' and 'line' are updated based on the status of the

 * read as follows:

 *

 * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL

 * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read

 *		       'line' is set to point at the read line

 * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL

 */

extern enum packet_read_status packet_reader_read(struct packet_reader *reader);

/*

 * Peek the next packet line without consuming it and return the status.

 * The next call to 'packet_reader_read()' will perform a read of the same line

 * that was peeked, consuming the line.

 *

 * Peeking multiple times without calling 'packet_reader_read()' will return

 * the same result.

 */

extern enum packet_read_status packet_reader_peek(struct packet_reader *reader);

#define DEFAULT_PACKET_MAX 1000

#define LARGE_PACKET_MAX 65520

#define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4)

extern char packet_buffer[LARGE_PACKET_MAX];

#endif