Prevent reply waiters from being blocked.
[free-sw/xcb/libxcb] / src / xcb_in.c
index 24fb041..7d34429 100644 (file)
 #include "xcb.h"
 #include "xcbext.h"
 #include "xcbint.h"
-
-#define XCBError 0
-#define XCBReply 1
+#if USE_POLL
+#include <poll.h>
+#endif
+#ifndef _WIN32
+#include <sys/select.h>
+#include <sys/socket.h>
+#endif
+
+#ifdef _WIN32
+#include "xcb_windefs.h"
+#endif /* _WIN32 */
+
+#define XCB_ERROR 0
+#define XCB_REPLY 1
+#define XCB_XGE_EVENT 35
+
+/* required for compiling for Win32 using MinGW */
+#ifndef MSG_WAITALL
+#define MSG_WAITALL 0
+#endif
 
 struct event_list {
-    XCBGenericEvent *event;
+    xcb_generic_event_t *event;
     struct event_list *next;
 };
 
@@ -50,32 +67,24 @@ struct reply_list {
 };
 
 typedef struct pending_reply {
-    unsigned int request;
+    uint64_t first_request;
+    uint64_t last_request;
     enum workarounds workaround;
     int flags;
     struct pending_reply *next;
 } pending_reply;
 
 typedef struct reader_list {
-    unsigned int request;
+    uint64_t request;
     pthread_cond_t *data;
     struct reader_list *next;
 } reader_list;
 
-static void wake_up_next_reader(XCBConnection *c)
+static int read_packet(xcb_connection_t *c)
 {
-    int pthreadret;
-    if(c->in.readers)
-        pthreadret = pthread_cond_signal(c->in.readers->data);
-    else
-        pthreadret = pthread_cond_signal(&c->in.event_cond);
-    assert(pthreadret == 0);
-}
-
-static int read_packet(XCBConnection *c)
-{
-    XCBGenericRep genrep;
+    xcb_generic_reply_t genrep;
     int length = 32;
+    int eventlength = 0; /* length after first 32 bytes for GenericEvents */
     void *buf;
     pending_reply *pend = 0;
     struct event_list *event;
@@ -88,13 +97,13 @@ static int read_packet(XCBConnection *c)
     memcpy(&genrep, c->in.queue, sizeof(genrep));
 
     /* Compute 32-bit sequence number of this packet. */
-    if((genrep.response_type & 0x7f) != XCBKeymapNotify)
+    if((genrep.response_type & 0x7f) != XCB_KEYMAP_NOTIFY)
     {
-        int lastread = c->in.request_read;
-        c->in.request_read = (lastread & 0xffff0000) | genrep.sequence;
-        if(c->in.request_read < lastread)
+        uint64_t lastread = c->in.request_read;
+        c->in.request_read = (lastread & UINT64_C(0xffffffffffff0000)) | genrep.sequence;
+        if(XCB_SEQUENCE_COMPARE(c->in.request_read, <, lastread))
             c->in.request_read += 0x10000;
-        if(c->in.request_read > c->in.request_expected)
+        if(XCB_SEQUENCE_COMPARE(c->in.request_read, >, c->in.request_expected))
             c->in.request_expected = c->in.request_read;
 
         if(c->in.request_read != lastread)
@@ -107,10 +116,10 @@ static int read_packet(XCBConnection *c)
             }
             c->in.request_completed = c->in.request_read - 1;
         }
-        if(genrep.response_type != XCBReply) /* error or event */
-            c->in.request_completed = c->in.request_read; /* XXX: does event/error imply no more replies? */
 
-        while(c->in.pending_replies && c->in.pending_replies->request <= c->in.request_completed)
+        while(c->in.pending_replies && 
+              c->in.pending_replies->workaround != WORKAROUND_EXTERNAL_SOCKET_OWNER &&
+             XCB_SEQUENCE_COMPARE (c->in.pending_replies->last_request, <=, c->in.request_completed))
         {
             pending_reply *oldpend = c->in.pending_replies;
             c->in.pending_replies = oldpend->next;
@@ -118,61 +127,96 @@ static int read_packet(XCBConnection *c)
                 c->in.pending_replies_tail = &c->in.pending_replies;
             free(oldpend);
         }
+
+        if(genrep.response_type == XCB_ERROR)
+            c->in.request_completed = c->in.request_read;
     }
 
-    if(genrep.response_type == XCBError || genrep.response_type == XCBReply)
+    if(genrep.response_type == XCB_ERROR || genrep.response_type == XCB_REPLY)
     {
         pend = c->in.pending_replies;
-        if(pend && pend->request != c->in.request_read)
+        if(pend &&
+           !(XCB_SEQUENCE_COMPARE(pend->first_request, <=, c->in.request_read) &&
+             (pend->workaround == WORKAROUND_EXTERNAL_SOCKET_OWNER ||
+              XCB_SEQUENCE_COMPARE(c->in.request_read, <=, pend->last_request))))
             pend = 0;
     }
 
     /* For reply packets, check that the entire packet is available. */
-    if(genrep.response_type == XCBReply)
+    if(genrep.response_type == XCB_REPLY)
     {
         if(pend && pend->workaround == WORKAROUND_GLX_GET_FB_CONFIGS_BUG)
         {
-            CARD32 *p = (CARD32 *) c->in.queue;
+            uint32_t *p = (uint32_t *) c->in.queue;
             genrep.length = p[2] * p[3] * 2;
         }
         length += genrep.length * 4;
     }
 
-    buf = malloc(length + (genrep.response_type == XCBReply ? 0 : sizeof(CARD32)));
+    /* XGE events may have sizes > 32 */
+    if (genrep.response_type == XCB_XGE_EVENT)
+        eventlength = genrep.length * 4;
+
+    buf = malloc(length + eventlength +
+            (genrep.response_type == XCB_REPLY ? 0 : sizeof(uint32_t)));
     if(!buf)
+    {
+        _xcb_conn_shutdown(c);
         return 0;
+    }
+
     if(_xcb_in_read_block(c, buf, length) <= 0)
     {
         free(buf);
         return 0;
     }
+
+    /* pull in XGE event data if available, append after event struct */
+    if (eventlength)
+    {
+        if(_xcb_in_read_block(c, &((xcb_generic_event_t*)buf)[1], eventlength) <= 0)
+        {
+            free(buf);
+            return 0;
+        }
+    }
+
     if(pend && (pend->flags & XCB_REQUEST_DISCARD_REPLY))
     {
         free(buf);
         return 1;
     }
 
-    if(genrep.response_type != XCBReply)
-        ((XCBGenericEvent *) buf)->full_sequence = c->in.request_read;
+    if(genrep.response_type != XCB_REPLY)
+        ((xcb_generic_event_t *) buf)->full_sequence = c->in.request_read;
 
     /* reply, or checked error */
-    if( genrep.response_type == XCBReply ||
-       (genrep.response_type == XCBError && pend && (pend->flags & XCB_REQUEST_CHECKED)))
+    if( genrep.response_type == XCB_REPLY ||
+       (genrep.response_type == XCB_ERROR && pend && (pend->flags & XCB_REQUEST_CHECKED)))
     {
         reader_list *reader;
         struct reply_list *cur = malloc(sizeof(struct reply_list));
         if(!cur)
+        {
+            _xcb_conn_shutdown(c);
+            free(buf);
             return 0;
+        }
         cur->reply = buf;
         cur->next = 0;
         *c->in.current_reply_tail = cur;
         c->in.current_reply_tail = &cur->next;
-        for(reader = c->in.readers; reader && reader->request <= c->in.request_read; reader = reader->next)
+        for(reader = c->in.readers; 
+           reader && 
+           XCB_SEQUENCE_COMPARE(reader->request, <=, c->in.request_read);
+           reader = reader->next)
+       {
+            pthread_cond_signal(reader->data);
             if(reader->request == c->in.request_read)
             {
-                pthread_cond_signal(reader->data);
                 break;
             }
+       }
         return 1;
     }
 
@@ -180,6 +224,7 @@ static int read_packet(XCBConnection *c)
     event = malloc(sizeof(struct event_list));
     if(!event)
     {
+        _xcb_conn_shutdown(c);
         free(buf);
         return 0;
     }
@@ -191,10 +236,10 @@ static int read_packet(XCBConnection *c)
     return 1; /* I have something for you... */
 }
 
-static XCBGenericEvent *get_event(XCBConnection *c)
+static xcb_generic_event_t *get_event(xcb_connection_t *c)
 {
     struct event_list *cur = c->in.events;
-    XCBGenericEvent *ret;
+    xcb_generic_event_t *ret;
     if(!c->in.events)
         return 0;
     ret = cur->event;
@@ -216,22 +261,39 @@ static void free_reply_list(struct reply_list *head)
     }
 }
 
-static int read_block(const int fd, void *buf, const size_t len)
+static int read_block(const int fd, void *buf, const ssize_t len)
 {
     int done = 0;
     while(done < len)
     {
-        int ret = read(fd, ((char *) buf) + done, len - done);
+        int ret = recv(fd, ((char *) buf) + done, len - done,MSG_WAITALL);
         if(ret > 0)
             done += ret;
+#ifndef _WIN32
         if(ret < 0 && errno == EAGAIN)
+#else
+        if(ret == SOCKET_ERROR && WSAGetLastError() == WSAEWOULDBLOCK)
+#endif /* !_Win32 */
         {
+#if USE_POLL
+            struct pollfd pfd;
+            pfd.fd = fd;
+            pfd.events = POLLIN;
+            pfd.revents = 0;
+            do {
+                ret = poll(&pfd, 1, -1);
+            } while (ret == -1 && errno == EINTR);
+#else
             fd_set fds;
             FD_ZERO(&fds);
             FD_SET(fd, &fds);
+
+           /* Initializing errno here makes sure that for Win32 this loop will execute only once */
+           errno = 0;  
            do {
                ret = select(fd + 1, &fds, 0, 0, 0);
            } while (ret == -1 && errno == EINTR);
+#endif /* USE_POLL */
         }
         if(ret <= 0)
             return ret;
@@ -239,7 +301,7 @@ static int read_block(const int fd, void *buf, const size_t len)
     return len;
 }
 
-static int poll_for_reply(XCBConnection *c, unsigned int request, void **reply, XCBGenericError **error)
+static int poll_for_reply(xcb_connection_t *c, uint64_t request, void **reply, xcb_generic_error_t **error)
 {
     struct reply_list *head;
 
@@ -248,7 +310,7 @@ static int poll_for_reply(XCBConnection *c, unsigned int request, void **reply,
         head = 0;
     /* We've read requests past the one we want, so if it has replies we have
      * them all and they're in the replies map. */
-    else if(request < c->in.request_read)
+    else if(XCB_SEQUENCE_COMPARE(request, <, c->in.request_read))
     {
         head = _xcb_map_remove(c->in.replies, request);
         if(head && head->next)
@@ -278,7 +340,7 @@ static int poll_for_reply(XCBConnection *c, unsigned int request, void **reply,
 
     if(head)
     {
-        if(((XCBGenericRep *) head->reply)->response_type == XCBError)
+        if(((xcb_generic_reply_t *) head->reply)->response_type == XCB_ERROR)
         {
             if(error)
                 *error = head->reply;
@@ -294,108 +356,207 @@ static int poll_for_reply(XCBConnection *c, unsigned int request, void **reply,
     return 1;
 }
 
+static void *wait_for_reply(xcb_connection_t *c, uint64_t request, xcb_generic_error_t **e)
+{
+    void *ret = 0;
+
+    /* If this request has not been written yet, write it. */
+    if(c->out.return_socket || _xcb_out_flush_to(c, request))
+    {
+        pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+        reader_list reader;
+        reader_list **prev_reader;
+
+        for(prev_reader = &c->in.readers; 
+           *prev_reader && 
+           XCB_SEQUENCE_COMPARE((*prev_reader)->request, <=, request);
+           prev_reader = &(*prev_reader)->next)
+       {
+            /* empty */;
+       }
+        reader.request = request;
+        reader.data = &cond;
+        reader.next = *prev_reader;
+        *prev_reader = &reader;
+
+        while(!poll_for_reply(c, request, &ret, e))
+            if(!_xcb_conn_wait(c, &cond, 0, 0))
+                break;
+
+        for(prev_reader = &c->in.readers;
+           *prev_reader && 
+           XCB_SEQUENCE_COMPARE((*prev_reader)->request, <=, request);
+           prev_reader = &(*prev_reader)->next)
+       {
+            if(*prev_reader == &reader)
+            {
+                *prev_reader = (*prev_reader)->next;
+                break;
+            }
+       }
+        pthread_cond_destroy(&cond);
+    }
+
+    _xcb_in_wake_up_next_reader(c);
+    return ret;
+}
+
+static uint64_t widen(xcb_connection_t *c, unsigned int request)
+{
+    uint64_t widened_request = (c->out.request & UINT64_C(0xffffffff00000000)) | request;
+    if(widened_request > c->out.request)
+        widened_request -= UINT64_C(1) << 32;
+    return widened_request;
+}
+
 /* Public interface */
 
-void *XCBWaitForReply(XCBConnection *c, unsigned int request, XCBGenericError **e)
+void *xcb_wait_for_reply(xcb_connection_t *c, unsigned int request, xcb_generic_error_t **e)
 {
-    pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
-    reader_list reader;
-    reader_list **prev_reader;
-    void *ret = 0;
+    void *ret;
     if(e)
         *e = 0;
+    if(c->has_error)
+        return 0;
 
     pthread_mutex_lock(&c->iolock);
+    ret = wait_for_reply(c, widen(c, request), e);
+    pthread_mutex_unlock(&c->iolock);
+    return ret;
+}
 
-    /* If this request has not been written yet, write it. */
-    if(!_xcb_out_flush_to(c, request))
-        goto done; /* error */
-
-    for(prev_reader = &c->in.readers; *prev_reader && (*prev_reader)->request <= request; prev_reader = &(*prev_reader)->next)
-        if((*prev_reader)->request == request)
-            goto done; /* error */
-
-    reader.request = request;
-    reader.data = &cond;
-    reader.next = *prev_reader;
-    *prev_reader = &reader;
-
-    /* If this request has not completed yet and has no reply waiting,
-     * wait for one. */
-    while(!poll_for_reply(c, request, &ret, e))
-        if(!_xcb_conn_wait(c, &cond, 0, 0))
-            goto done;
-
-done:
-    for(prev_reader = &c->in.readers; *prev_reader && (*prev_reader)->request <= request; prev_reader = &(*prev_reader)->next)
-        if(*prev_reader == &reader)
-        {
-            *prev_reader = (*prev_reader)->next;
+static void insert_pending_discard(xcb_connection_t *c, pending_reply **prev_next, uint64_t seq)
+{
+    pending_reply *pend;
+    pend = malloc(sizeof(*pend));
+    if(!pend)
+    {
+        _xcb_conn_shutdown(c);
+        return;
+    }
+
+    pend->first_request = seq;
+    pend->last_request = seq;
+    pend->workaround = 0;
+    pend->flags = XCB_REQUEST_DISCARD_REPLY;
+    pend->next = *prev_next;
+    *prev_next = pend;
+
+    if(!pend->next)
+        c->in.pending_replies_tail = &pend->next;
+}
+
+static void discard_reply(xcb_connection_t *c, uint64_t request)
+{
+    void *reply;
+    pending_reply **prev_pend;
+
+    /* Free any replies or errors that we've already read. Stop if
+     * xcb_wait_for_reply would block or we've run out of replies. */
+    while(poll_for_reply(c, request, &reply, 0) && reply)
+        free(reply);
+
+    /* If we've proven there are no more responses coming, we're done. */
+    if(XCB_SEQUENCE_COMPARE(request, <=, c->in.request_completed))
+        return;
+
+    /* Walk the list of pending requests. Mark the first match for deletion. */
+    for(prev_pend = &c->in.pending_replies; *prev_pend; prev_pend = &(*prev_pend)->next)
+    {
+        if(XCB_SEQUENCE_COMPARE((*prev_pend)->first_request, >, request))
             break;
+
+        if((*prev_pend)->first_request == request)
+        {
+            /* Pending reply found. Mark for discard: */
+            (*prev_pend)->flags |= XCB_REQUEST_DISCARD_REPLY;
+            return;
         }
-    pthread_cond_destroy(&cond);
+    }
+
+    /* Pending reply not found (likely due to _unchecked request). Create one: */
+    insert_pending_discard(c, prev_pend, request);
+}
 
-    wake_up_next_reader(c);
+void xcb_discard_reply(xcb_connection_t *c, unsigned int sequence)
+{
+    if(c->has_error)
+        return;
+
+    /* If an error occurred when issuing the request, fail immediately. */
+    if(!sequence)
+        return;
+
+    pthread_mutex_lock(&c->iolock);
+    discard_reply(c, widen(c, sequence));
     pthread_mutex_unlock(&c->iolock);
-    return ret;
 }
 
-int XCBPollForReply(XCBConnection *c, unsigned int request, void **reply, XCBGenericError **error)
+int xcb_poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error)
 {
     int ret;
+    if(c->has_error)
+    {
+        *reply = 0;
+        if(error)
+            *error = 0;
+        return 1; /* would not block */
+    }
     assert(reply != 0);
     pthread_mutex_lock(&c->iolock);
-    ret = poll_for_reply(c, request, reply, error);
+    ret = poll_for_reply(c, widen(c, request), reply, error);
     pthread_mutex_unlock(&c->iolock);
     return ret;
 }
 
-XCBGenericEvent *XCBWaitEvent(XCBConnection *c)
-{
-    return XCBWaitForEvent(c);
-}
-
-XCBGenericEvent *XCBWaitForEvent(XCBConnection *c)
+xcb_generic_event_t *xcb_wait_for_event(xcb_connection_t *c)
 {
-    XCBGenericEvent *ret;
+    xcb_generic_event_t *ret;
+    if(c->has_error)
+        return 0;
     pthread_mutex_lock(&c->iolock);
     /* get_event returns 0 on empty list. */
     while(!(ret = get_event(c)))
         if(!_xcb_conn_wait(c, &c->in.event_cond, 0, 0))
             break;
 
-    wake_up_next_reader(c);
+    _xcb_in_wake_up_next_reader(c);
     pthread_mutex_unlock(&c->iolock);
     return ret;
 }
 
-XCBGenericEvent *XCBPollForEvent(XCBConnection *c, int *error)
+xcb_generic_event_t *xcb_poll_for_event(xcb_connection_t *c)
 {
-    XCBGenericEvent *ret = 0;
-    pthread_mutex_lock(&c->iolock);
-    if(error)
-        *error = 0;
-    /* FIXME: follow X meets Z architecture changes. */
-    if(_xcb_in_read(c))
-        ret = get_event(c);
-    else if(error)
-        *error = -1;
-    else
+    xcb_generic_event_t *ret = 0;
+    if(!c->has_error)
     {
-        fprintf(stderr, "XCBPollForEvent: I/O error occured, but no handler provided.\n");
-        abort();
+        pthread_mutex_lock(&c->iolock);
+        /* FIXME: follow X meets Z architecture changes. */
+        ret = get_event(c);
+        if(!ret && _xcb_in_read(c)) /* _xcb_in_read shuts down the connection on error */
+            ret = get_event(c);
+        pthread_mutex_unlock(&c->iolock);
     }
-    pthread_mutex_unlock(&c->iolock);
     return ret;
 }
 
-unsigned int XCBGetRequestRead(XCBConnection *c)
+xcb_generic_error_t *xcb_request_check(xcb_connection_t *c, xcb_void_cookie_t cookie)
 {
-    unsigned int ret;
+    uint64_t request;
+    xcb_generic_error_t *ret = 0;
+    void *reply;
+    if(c->has_error)
+        return 0;
     pthread_mutex_lock(&c->iolock);
-    /* FIXME: follow X meets Z architecture changes. */
-    _xcb_in_read(c);
-    ret = c->in.request_read;
+    request = widen(c, cookie.sequence);
+    if(XCB_SEQUENCE_COMPARE(request, >=, c->in.request_expected)
+       && XCB_SEQUENCE_COMPARE(request, >, c->in.request_completed))
+    {
+        _xcb_out_send_sync(c);
+        _xcb_out_flush_to(c, c->out.request);
+    }
+    reply = wait_for_reply(c, request, &ret);
+    assert(!reply);
     pthread_mutex_unlock(&c->iolock);
     return ret;
 }
@@ -444,34 +605,66 @@ void _xcb_in_destroy(_xcb_in *in)
     }
 }
 
-int _xcb_in_expect_reply(XCBConnection *c, unsigned int request, enum workarounds workaround, int flags)
+void _xcb_in_wake_up_next_reader(xcb_connection_t *c)
+{
+    int pthreadret;
+    if(c->in.readers)
+        pthreadret = pthread_cond_signal(c->in.readers->data);
+    else
+        pthreadret = pthread_cond_signal(&c->in.event_cond);
+    assert(pthreadret == 0);
+}
+
+int _xcb_in_expect_reply(xcb_connection_t *c, uint64_t request, enum workarounds workaround, int flags)
 {
-    if(workaround != WORKAROUND_NONE || flags != 0)
+    pending_reply *pend = malloc(sizeof(pending_reply));
+    assert(workaround != WORKAROUND_NONE || flags != 0);
+    if(!pend)
     {
-        pending_reply *pend = malloc(sizeof(pending_reply));
-        if(!pend)
-            return 0;
-        pend->request = request;
-        pend->workaround = workaround;
-        pend->flags = flags;
-        pend->next = 0;
-        *c->in.pending_replies_tail = pend;
-        c->in.pending_replies_tail = &pend->next;
+        _xcb_conn_shutdown(c);
+        return 0;
     }
+    pend->first_request = pend->last_request = request;
+    pend->workaround = workaround;
+    pend->flags = flags;
+    pend->next = 0;
+    *c->in.pending_replies_tail = pend;
+    c->in.pending_replies_tail = &pend->next;
     return 1;
 }
 
-int _xcb_in_read(XCBConnection *c)
+void _xcb_in_replies_done(xcb_connection_t *c)
+{
+    struct pending_reply *pend;
+    if (c->in.pending_replies_tail != &c->in.pending_replies)
+    {
+        pend = container_of(c->in.pending_replies_tail, struct pending_reply, next);
+        if(pend->workaround == WORKAROUND_EXTERNAL_SOCKET_OWNER)
+        {
+            pend->last_request = c->out.request;
+            pend->workaround = WORKAROUND_NONE;
+        }
+    }
+}
+
+int _xcb_in_read(xcb_connection_t *c)
 {
-    int n = read(c->fd, c->in.queue + c->in.queue_len, sizeof(c->in.queue) - c->in.queue_len);
+    int n = recv(c->fd, c->in.queue + c->in.queue_len, sizeof(c->in.queue) - c->in.queue_len,MSG_WAITALL);
     if(n > 0)
         c->in.queue_len += n;
     while(read_packet(c))
         /* empty */;
-    return (n > 0) || (n < 0 && errno == EAGAIN);
+#ifndef _WIN32
+    if((n > 0) || (n < 0 && errno == EAGAIN))
+#else
+    if((n > 0) || (n < 0 && WSAGetLastError() == WSAEWOULDBLOCK))
+#endif /* !_WIN32 */
+        return 1;
+    _xcb_conn_shutdown(c);
+    return 0;
 }
 
-int _xcb_in_read_block(XCBConnection *c, void *buf, int len)
+int _xcb_in_read_block(xcb_connection_t *c, void *buf, int len)
 {
     int done = c->in.queue_len;
     if(len < done)
@@ -485,7 +678,10 @@ int _xcb_in_read_block(XCBConnection *c, void *buf, int len)
     {
         int ret = read_block(c->fd, (char *) buf + done, len - done);
         if(ret <= 0)
+        {
+            _xcb_conn_shutdown(c);
             return ret;
+        }
     }
 
     return len;