/* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 * 

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 * 

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 * 

 * Except as contained in this notice, the names of the authors or their

 * institutions shall not be used in advertising or otherwise to promote the

 * sale, use or other dealings in this Software without prior written

 * authorization from the authors.

 */

/* Stuff that sends stuff to the server. */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <assert.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include "xcb.h"

#include "xcbext.h"

#include "xcbint.h"

#include "bigreq.h"

static inline void send_request(xcb_connection_t *c, int isvoid, enum workarounds workaround, int flags, struct iovec *vector, int count)

{

    if(c->has_error)

        return;

    ++c->out.request;

    if(!isvoid)

        c->in.request_expected = c->out.request;

    if(workaround != WORKAROUND_NONE || flags != 0)

        _xcb_in_expect_reply(c, c->out.request, workaround, flags);

    while(count && c->out.queue_len + vector[0].iov_len <= sizeof(c->out.queue))

    {

        memcpy(c->out.queue + c->out.queue_len, vector[0].iov_base, vector[0].iov_len);

        c->out.queue_len += vector[0].iov_len;

        vector[0].iov_base = (char *) vector[0].iov_base + vector[0].iov_len;

        vector[0].iov_len = 0;

        ++vector, --count;

    }

    if(!count)

        return;

    --vector, ++count;

    vector[0].iov_base = c->out.queue;

    vector[0].iov_len = c->out.queue_len;

    c->out.queue_len = 0;

    _xcb_out_send(c, vector, count);

}

static void send_sync(xcb_connection_t *c)

{

    static const union {

        struct {

            uint8_t major;

            uint8_t pad;

            uint16_t len;

        } fields;

        uint32_t packet;

    } sync_req = { { /* GetInputFocus */ 43, 0, 1 } };

    struct iovec vector[2];

    vector[1].iov_base = (char *) &sync_req;

    vector[1].iov_len = sizeof(sync_req);

    send_request(c, 0, WORKAROUND_NONE, XCB_REQUEST_DISCARD_REPLY, vector + 1, 1);

}

static void get_socket_back(xcb_connection_t *c)

{

    while(c->out.return_socket && c->out.socket_moving)

        pthread_cond_wait(&c->out.socket_cond, &c->iolock);

    if(!c->out.return_socket)

        return;

    c->out.socket_moving = 1;

    pthread_mutex_unlock(&c->iolock);

    c->out.return_socket(c->out.socket_closure);

    pthread_mutex_lock(&c->iolock);

    c->out.socket_moving = 0;

    pthread_cond_broadcast(&c->out.socket_cond);

    c->out.return_socket = 0;

    c->out.socket_closure = 0;

    _xcb_in_replies_done(c);

}

static void prepare_socket_request(xcb_connection_t *c)

{

    /* We're about to append data to out.queue, so we need to

     * atomically test for an external socket owner *and* some other

     * thread currently writing.

     *

     * If we have an external socket owner, we have to get the socket back

     * before we can use it again.

     *

     * If some other thread is writing to the socket, we assume it's

     * writing from out.queue, and so we can't stick data there.

     *

     * We satisfy this condition by first calling get_socket_back

     * (which may drop the lock, but will return when XCB owns the

     * socket again) and then checking for another writing thread and

     * escaping the loop if we're ready to go.

     */

    for (;;) {

        if(c->has_error)

            return;

        get_socket_back(c);

        if (!c->out.writing)

            break;

        pthread_cond_wait(&c->out.cond, &c->iolock);

    }

}

/* Public interface */

void xcb_prefetch_maximum_request_length(xcb_connection_t *c)

{

    if(c->has_error)

        return;

    pthread_mutex_lock(&c->out.reqlenlock);

    if(c->out.maximum_request_length_tag == LAZY_NONE)

    {

        const xcb_query_extension_reply_t *ext;

        ext = xcb_get_extension_data(c, &xcb_big_requests_id);

        if(ext && ext->present)

        {

            c->out.maximum_request_length_tag = LAZY_COOKIE;

            c->out.maximum_request_length.cookie = xcb_big_requests_enable(c);

        }

        else

        {

            c->out.maximum_request_length_tag = LAZY_FORCED;

            c->out.maximum_request_length.value = c->setup->maximum_request_length;

        }

    }

    pthread_mutex_unlock(&c->out.reqlenlock);

}

uint32_t xcb_get_maximum_request_length(xcb_connection_t *c)

{

    if(c->has_error)

        return 0;

    xcb_prefetch_maximum_request_length(c);

    pthread_mutex_lock(&c->out.reqlenlock);

    if(c->out.maximum_request_length_tag == LAZY_COOKIE)

    {

        xcb_big_requests_enable_reply_t *r = xcb_big_requests_enable_reply(c, c->out.maximum_request_length.cookie, 0);

        c->out.maximum_request_length_tag = LAZY_FORCED;

        if(r)

        {

            c->out.maximum_request_length.value = r->maximum_request_length;

            free(r);

        }

        else

            c->out.maximum_request_length.value = c->setup->maximum_request_length;

    }

    pthread_mutex_unlock(&c->out.reqlenlock);

    return c->out.maximum_request_length.value;

}

static void close_fds(int *fds, unsigned int num_fds)

{

    for (unsigned int index = 0; index < num_fds; index++)

        close(fds[index]);

}

static void send_fds(xcb_connection_t *c, int *fds, unsigned int num_fds)

{

#if HAVE_SENDMSG

    /* Calling _xcb_out_flush_to() can drop the iolock and wait on a condition

     * variable if another thread is currently writing (c->out.writing > 0).

     * This call waits for writers to be done and thus _xcb_out_flush_to() will

     * do the work itself (in which case we are a writer and

     * prepare_socket_request() will wait for us to be done if another threads

     * tries to send fds, too). Thanks to this, we can atomically write out FDs.

     */

    prepare_socket_request(c);

    while (num_fds > 0) {

        while (c->out.out_fd.nfd == XCB_MAX_PASS_FD && !c->has_error) {

            /* XXX: if c->out.writing > 0, this releases the iolock and

             * potentially allows other threads to interfere with their own fds.

             */

            _xcb_out_flush_to(c, c->out.request);

            if (c->out.out_fd.nfd == XCB_MAX_PASS_FD) {

                /* We need some request to send FDs with */

                _xcb_out_send_sync(c);

            }

        }

        if (c->has_error)

            break;

        c->out.out_fd.fd[c->out.out_fd.nfd++] = fds[0];

        fds++;

        num_fds--;

    }

#endif

    close_fds(fds, num_fds);

}

uint64_t xcb_send_request_with_fds64(xcb_connection_t *c, int flags, struct iovec *vector,

                const xcb_protocol_request_t *req, unsigned int num_fds, int *fds)

{

    uint64_t request;

    uint32_t prefix[2];

    int veclen = req->count;

    enum workarounds workaround = WORKAROUND_NONE;

    if(c->has_error) {

        close_fds(fds, num_fds);

        return 0;

    }

    assert(c != 0);

    assert(vector != 0);

    assert(req->count > 0);

    if(!(flags & XCB_REQUEST_RAW))

    {

        static const char pad[3];

        unsigned int i;

        uint16_t shortlen = 0;

        size_t longlen = 0;

        assert(vector[0].iov_len >= 4);

        /* set the major opcode, and the minor opcode for extensions */

        if(req->ext)

        {

            const xcb_query_extension_reply_t *extension = xcb_get_extension_data(c, req->ext);

            if(!(extension && extension->present))

            {

                close_fds(fds, num_fds);

                _xcb_conn_shutdown(c, XCB_CONN_CLOSED_EXT_NOTSUPPORTED);

                return 0;

            }

            ((uint8_t *) vector[0].iov_base)[0] = extension->major_opcode;

            ((uint8_t *) vector[0].iov_base)[1] = req->opcode;

        }

        else

            ((uint8_t *) vector[0].iov_base)[0] = req->opcode;

        /* put together the length field, possibly using BIGREQUESTS */

        for(i = 0; i < req->count; ++i)

        {

            longlen += vector[i].iov_len;

            if(!vector[i].iov_base)

            {

                vector[i].iov_base = (char *) pad;

                assert(vector[i].iov_len <= sizeof(pad));

            }

        }

        assert((longlen & 3) == 0);

        longlen >>= 2;

        if(longlen <= c->setup->maximum_request_length)

        {

            /* we don't need BIGREQUESTS. */

            shortlen = longlen;

            longlen = 0;

        }

        else if(longlen > xcb_get_maximum_request_length(c))

        {

            close_fds(fds, num_fds);

            _xcb_conn_shutdown(c, XCB_CONN_CLOSED_REQ_LEN_EXCEED);

            return 0; /* server can't take this; maybe need BIGREQUESTS? */

        }

        /* set the length field. */

        ((uint16_t *) vector[0].iov_base)[1] = shortlen;

        if(!shortlen)

        {

            prefix[0] = ((uint32_t *) vector[0].iov_base)[0];

            prefix[1] = ++longlen;

            vector[0].iov_base = (uint32_t *) vector[0].iov_base + 1;

            vector[0].iov_len -= sizeof(uint32_t);

            --vector, ++veclen;

            vector[0].iov_base = prefix;

            vector[0].iov_len = sizeof(prefix);

        }

    }

    flags &= ~XCB_REQUEST_RAW;

    /* do we need to work around the X server bug described in glx.xml? */

    /* XXX: GetFBConfigs won't use BIG-REQUESTS in any sane

     * configuration, but that should be handled here anyway. */

    if(req->ext && !req->isvoid && !strcmp(req->ext->name, "GLX") &&

            ((req->opcode == 17 && ((uint32_t *) vector[0].iov_base)[1] == 0x10004) ||

             req->opcode == 21))

        workaround = WORKAROUND_GLX_GET_FB_CONFIGS_BUG;

    /* get a sequence number and arrange for delivery. */

    pthread_mutex_lock(&c->iolock);

    /* send FDs before establishing a good request number, because this might

     * call send_sync(), too

     */

    send_fds(c, fds, num_fds);

    prepare_socket_request(c);

    /* send GetInputFocus (sync_req) when 64k-2 requests have been sent without

     * a reply.

     * Also send sync_req (could use NoOp) at 32-bit wrap to avoid having

     * applications see sequence 0 as that is used to indicate

     * an error in sending the request

     */

    while ((req->isvoid && c->out.request == c->in.request_expected + (1 << 16) - 2) ||

           (unsigned int) (c->out.request + 1) == 0)

    {

        send_sync(c);

        prepare_socket_request(c);

    }

    send_request(c, req->isvoid, workaround, flags, vector, veclen);

    request = c->has_error ? 0 : c->out.request;

    pthread_mutex_unlock(&c->iolock);

    return request;

}

/* request number are actually uint64_t internally but keep API compat with unsigned int */

unsigned int xcb_send_request_with_fds(xcb_connection_t *c, int flags, struct iovec *vector,

        const xcb_protocol_request_t *req, unsigned int num_fds, int *fds)

{

    return xcb_send_request_with_fds64(c, flags, vector, req, num_fds, fds);

}

uint64_t xcb_send_request64(xcb_connection_t *c, int flags, struct iovec *vector, const xcb_protocol_request_t *req)

{

    return xcb_send_request_with_fds64(c, flags, vector, req, 0, NULL);

}

/* request number are actually uint64_t internally but keep API compat with unsigned int */

unsigned int xcb_send_request(xcb_connection_t *c, int flags, struct iovec *vector, const xcb_protocol_request_t *req)

{

    return xcb_send_request64(c, flags, vector, req);

}

void

xcb_send_fd(xcb_connection_t *c, int fd)

{

    int fds[1] = { fd };

    if (c->has_error) {

        close(fd);

        return;

    }

    pthread_mutex_lock(&c->iolock);

    send_fds(c, &fds[0], 1);

    pthread_mutex_unlock(&c->iolock);

}

int xcb_take_socket(xcb_connection_t *c, void (*return_socket)(void *closure), void *closure, int flags, uint64_t *sent)

{

    int ret;

    if(c->has_error)

        return 0;

    pthread_mutex_lock(&c->iolock);

    get_socket_back(c);

    /* _xcb_out_flush may drop the iolock allowing other threads to

     * write requests, so keep flushing until we're done

     */

    do

        ret = _xcb_out_flush_to(c, c->out.request);

    while (ret && c->out.request != c->out.request_written);

    if(ret)

    {

        c->out.return_socket = return_socket;

        c->out.socket_closure = closure;

        if(flags) {

            /* c->out.request + 1 will be the first request sent by the external

             * socket owner. If the socket is returned before this request is sent

             * it will be detected in _xcb_in_replies_done and this pending_reply

             * will be discarded.

             */

            _xcb_in_expect_reply(c, c->out.request + 1, WORKAROUND_EXTERNAL_SOCKET_OWNER, flags);

        }

        assert(c->out.request == c->out.request_written);

        *sent = c->out.request;

    }

    pthread_mutex_unlock(&c->iolock);

    return ret;

}

int xcb_writev(xcb_connection_t *c, struct iovec *vector, int count, uint64_t requests)

{

    int ret;

    if(c->has_error)

        return 0;

    pthread_mutex_lock(&c->iolock);

    c->out.request += requests;

    ret = _xcb_out_send(c, vector, count);

    pthread_mutex_unlock(&c->iolock);

    return ret;

}

int xcb_flush(xcb_connection_t *c)

{

    int ret;

    if(c->has_error)

        return 0;

    pthread_mutex_lock(&c->iolock);

    ret = _xcb_out_flush_to(c, c->out.request);

    pthread_mutex_unlock(&c->iolock);

    return ret;

}

/* Private interface */

int _xcb_out_init(_xcb_out *out)

{

    if(pthread_cond_init(&out->socket_cond, 0))

        return 0;

    out->return_socket = 0;

    out->socket_closure = 0;

    out->socket_moving = 0;

    if(pthread_cond_init(&out->cond, 0))

        return 0;

    out->writing = 0;

    out->queue_len = 0;

    out->request = 0;

    out->request_written = 0;

    if(pthread_mutex_init(&out->reqlenlock, 0))

        return 0;

    out->maximum_request_length_tag = LAZY_NONE;

    return 1;

}

void _xcb_out_destroy(_xcb_out *out)

{

    pthread_cond_destroy(&out->cond);

    pthread_mutex_destroy(&out->reqlenlock);

}

int _xcb_out_send(xcb_connection_t *c, struct iovec *vector, int count)

{

    int ret = 1;

    while(ret && count)

        ret = _xcb_conn_wait(c, &c->out.cond, &vector, &count);

    c->out.request_written = c->out.request;

    pthread_cond_broadcast(&c->out.cond);

    _xcb_in_wake_up_next_reader(c);

    return ret;

}

void _xcb_out_send_sync(xcb_connection_t *c)

{

    prepare_socket_request(c);

    send_sync(c);

}

int _xcb_out_flush_to(xcb_connection_t *c, uint64_t request)

{

    assert(XCB_SEQUENCE_COMPARE(request, <=, c->out.request));

    if(XCB_SEQUENCE_COMPARE(c->out.request_written, >=, request))

        return 1;

    if(c->out.queue_len)

    {

        struct iovec vec;

        vec.iov_base = c->out.queue;

        vec.iov_len = c->out.queue_len;

        c->out.queue_len = 0;

        return _xcb_out_send(c, &vec, 1);

    }

    while(c->out.writing)

        pthread_cond_wait(&c->out.cond, &c->iolock);

    assert(XCB_SEQUENCE_COMPARE(c->out.request_written, >=, request));

    return 1;

}