Introducing curl_easy_pause() and new magic return codes for both the read

and the write callbacks that now can make a connection's reading and/or
writing get paused.

1 files changed, 71 insertions, 3 deletions

diff --git a/lib/sendf.c b/lib/sendf.c
index b33277ac3..32a8655b2 100644
--- a/lib/sendf.c
+++ b/lib/sendf.c
@@ -376,6 +376,36 @@ CURLcode Curl_write(struct connectdata *conn,
   return retcode;
 }
 
+static CURLcode pausewrite(struct SessionHandle *data,
+                           int type, /* what type of data */
+                           char *ptr,
+                           size_t len)
+{
+  /* signalled to pause sending on this connection, but since we have data
+     we want to send we need to dup it to save a copy for when the sending
+     is again enabled */
+  struct SingleRequest *k = &data->req;
+  char *dupl = malloc(len);
+  if(!dupl)
+    return CURLE_OUT_OF_MEMORY;
+
+  memcpy(dupl, ptr, len);
+
+  /* store this information in the state struct for later use */
+  data->state.tempwrite = dupl;
+  data->state.tempwritesize = len;
+  data->state.tempwritetype = type;
+
+  /* mark the connection as RECV paused */
+  k->keepon |= KEEP_READ_PAUSE;
+
+  DEBUGF(infof(data, "Pausing with %d bytes in buffer for type %02x\n",
+               (int)len, type));
+
+  return CURLE_OK;
+}
+
+
 /* client_write() sends data to the write callback(s)
 
    The bit pattern defines to what "streams" to write to. Body and/or header.
@@ -390,8 +420,37 @@ CURLcode Curl_client_write(struct connectdata *conn,
   size_t wrote;
 
   if(data->state.cancelled) {
-      /* We just suck everything into a black hole */
-      return CURLE_OK;
+    /* We just suck everything into a black hole */
+    return CURLE_OK;
+  }
+
+  /* If reading is actually paused, we're forced to append this chunk of data
+     to the already held data, but only if it is the same type as otherwise it
+     can't work and it'll return error instead. */
+  if(data->req.keepon & KEEP_READ_PAUSE) {
+    size_t newlen;
+    char *newptr;
+    if(type != data->state.tempwritetype)
+      /* major internal confusion */
+      return CURLE_RECV_ERROR;
+
+    /* figure out the new size of the data to save */
+    newlen = len + data->state.tempwritesize;
+    /* allocate the new memory area */
+    newptr = malloc(newlen);
+    if(!newptr)
+      return CURLE_OUT_OF_MEMORY;
+    /* copy the previously held data to the new area */
+    memcpy(newptr, data->state.tempwrite, data->state.tempwritesize);
+    /* copy the new data to the end of the new area */
+    memcpy(newptr + data->state.tempwritesize, ptr, len);
+    /* free the old data */
+    free(data->state.tempwrite);
+    /* update the pointer and the size */
+    data->state.tempwrite = newptr;
+    data->state.tempwritesize = newlen;
+
+    return CURLE_OK;
   }
 
   if(0 == len)
@@ -422,8 +481,11 @@ CURLcode Curl_client_write(struct connectdata *conn,
       wrote = len;
     }
 
+    if(CURL_WRITEFUNC_PAUSE == wrote)
+      return pausewrite(data, type, ptr, len);
+
     if(wrote != len) {
-      failf (data, "Failed writing body");
+      failf(data, "Failed writing body (%d != %d)", (int)wrote, (int)len);
       return CURLE_WRITE_ERROR;
     }
   }
@@ -441,6 +503,12 @@ CURLcode Curl_client_write(struct connectdata *conn,
        regardless of the ftp transfer mode (ASCII/Image) */
 
     wrote = writeit(ptr, 1, len, data->set.writeheader);
+    if(CURL_WRITEFUNC_PAUSE == wrote)
+      /* here we pass in the HEADER bit only since if this was body as well
+         then it was passed already and clearly that didn't trigger the pause,
+         so this is saved for later with the HEADER bit only */
+      return pausewrite(data, CLIENTWRITE_HEADER, ptr, len);
+
     if(wrote != len) {
       failf (data, "Failed writing header");
       return CURLE_WRITE_ERROR;