ppb_url_loader: stop using file-backed NPN_PostURL/NPN_PostURLNotify

In bug 1352572 Firefox removed file support from NPN_PostURL and
NPN_PostURLNotify. It's now required to construct entire request body
in continuous chunk of memory.

src/ppb_url_loader.c

@@ -138,41 +138,33 @@ url_loader_open_ptac(void *user_data)
 
     if (p->method == PP_METHOD_POST) {
         // POST request
-        char   *tmpfname;
-        int     fd;
-        FILE   *fp = NULL;
-        int     need_newline = 0;
 
-        tmpfname = g_strdup_printf("/tmp/FreshPostBodyXXXXXX");    // TODO: make configurable
-
-        fd = mkstemp(tmpfname);
-        if (fd < 0) {
+        int need_newline = 0;
+        GString *buf = g_string_new(NULL);
+        if (!buf) {
             p->retval = NPERR_GENERIC_ERROR;
-            goto err;
-        }
-
-        fp = fdopen(fd, "wb+");
-        if (!fp) {
-            close(fd);
-            p->retval = NPERR_GENERIC_ERROR;
-            goto err;
+            goto quit;
         }
 
         if (p->request_headers) {
-            fprintf(fp, "%s\n", p->request_headers);
+            g_string_append_printf(buf, "%s\r\n", p->request_headers);
             need_newline = 1;
         }
+
         if (p->custom_referrer_url) {
             // the header name should be "referer", that's how it's spelled in HTTP spec
-            fprintf(fp, "Referer: %s\n", p->custom_referrer_url);
+            g_string_append_printf(buf, "Referer: %s\r\n", p->custom_referrer_url);
             need_newline = 1;
         }
+
         if (p->custom_content_transfer_encoding) {
-            fprintf(fp, "Content-Transfer-Encoding: %s\n", p->custom_content_transfer_encoding);
+            g_string_append_printf(buf, "Content-Transfer-Encoding: %s\r\n",
+                                   p->custom_content_transfer_encoding);
             need_newline = 1;
         }
+
         if (p->custom_user_agent) {
-            fprintf(fp, "User-Agent: %s\n", p->custom_user_agent);
+            g_string_append_printf(buf, "User-Agent: %s\r\n", p->custom_user_agent);
             need_newline = 1;
         }
 
@@ -185,38 +177,33 @@ url_loader_open_ptac(void *user_data)
             }
 
             if (post_len > 0) {
-                fprintf(fp, "Content-Length: %"PRIu64"\n", (uint64_t)post_len);
+                g_string_append_printf(buf, "Content-Length: %"PRIu64"\r\n", (uint64_t)post_len);
                 need_newline = 1;
             }
         }
 
         if (need_newline)
-            fprintf(fp, "\n");
+            g_string_append(buf, "\r\n");
 
         if (p->post_data) {
             for (guint k = 0; k < p->post_data->len; k ++)
-                post_data_write_to_fp(p->post_data, k, fp);
+                post_data_write_to_gstring(p->post_data, k, buf);
         }
 
-        fclose(fp); // flush all unwritten data and close the file
-        fp = NULL;  // avoid calling fclose() twice
-
         if (p->target) {
-            p->retval = npn.posturl(pp_i->npp, p->url, p->target, strlen(tmpfname), tmpfname, true);
+            p->retval = npn.posturl(pp_i->npp, p->url, p->target, buf->len, buf->str, false);
             if (p->retval != NPERR_NO_ERROR)
                 trace_error("%s, NPN_PostURL returned %d\n", __func__, p->retval);
 
         } else {
-            p->retval = npn.posturlnotify(pp_i->npp, p->url, NULL, strlen(tmpfname), tmpfname, true,
+            p->retval = npn.posturlnotify(pp_i->npp, p->url, NULL, buf->len, buf->str, false,
                                           (void*)(size_t)p->loader);
             if (p->retval != NPERR_NO_ERROR)
                 trace_error("%s, NPN_PostURLNotify returned %d\n", __func__, p->retval);
         }
 err:
-        if (fp)
-            fclose(fp);
-        unlink(tmpfname);
-        g_free(tmpfname);
+        g_string_free(buf, TRUE);
+
     } else {
         // GET request
         if (p->target) {

src/ppb_url_request_info.c

@@ -361,7 +361,7 @@ post_data_free(GArray *post_data)
 }
 
 void
-post_data_write_to_fp(GArray *post_data, guint idx, FILE *fp)
+post_data_write_to_gstring(GArray *post_data, guint idx, GString *s)
 {
     char buf[128 * 1024];
     struct post_data_item_s *pdi = &g_array_index(post_data, struct post_data_item_s, idx);
@@ -378,14 +378,14 @@ post_data_write_to_fp(GArray *post_data, guint idx, FILE *fp)
             ssize_t read_bytes = RETRY_ON_EINTR(read(fd, buf, MIN(to_write, sizeof(buf))));
             if (read_bytes == -1)
                 goto err;
-            fwrite(buf, 1, (size_t)read_bytes, fp);
+            g_string_append_len(s, buf, (size_t)read_bytes);
             to_write -= read_bytes;
         }
 err:
         if (fd >= 0)
             close(fd);
     } else {
-        fwrite(pdi->data, 1, pdi->len, fp);
+        g_string_append_len(s, pdi->data, pdi->len);
     }
 }
 

src/ppb_url_request_info.h

@@ -54,7 +54,7 @@ size_t
 post_data_get_all_item_length(GArray *post_data);
 
 void
-post_data_write_to_fp(GArray *post_data, guint idx, FILE *fp);
+post_data_write_to_gstring(GArray *post_data, guint idx, GString *buf);
 
 PP_Resource
 ppb_url_request_info_create(PP_Instance instance);