emscripten_async_wget_data

src/library_browser.js

@@ -336,19 +336,19 @@ mergeInto(LibraryManager.library, {
       xhr.send(null);
     },
 
-    asyncLoad: function(url, onload, onerror) {
+    asyncLoad: function(url, onload, onerror, noRunDep) {
       Browser.xhrLoad(url, function(arrayBuffer) {
         assert(arrayBuffer, 'Loading data file "' + url + '" failed (no arrayBuffer).');
         onload(new Uint8Array(arrayBuffer));
-        removeRunDependency('al ' + url);
+        if (!noRunDep) removeRunDependency('al ' + url);
       }, function(event) {
         if (onerror) {
           onerror();
         } else {
           throw 'Loading data file "' + url + '" failed.';
         }
       });
-      addRunDependency('al ' + url);
+      if (!noRunDep) addRunDependency('al ' + url);
     },
 
     resizeListeners: [],
@@ -381,10 +381,21 @@ mergeInto(LibraryManager.library, {
       },
       function() {
         if (onerror) FUNCTION_TABLE[onerror](file);
-      }
+      } 
     );
   },
 
+  emscripten_async_wget_data: function(url, arg, onload, onerror) {
+    Browser.asyncLoad(Pointer_stringify(url), function(byteArray) {
+      var buffer = _malloc(byteArray.length);
+      HEAPU8.set(byteArray, buffer);
+      FUNCTION_TABLE[onload](arg, buffer, byteArray.length);
+      _free(buffer);
+    }, function() {
+      if (onerror) FUNCTION_TABLE[onerror](arg);
+    }, true /* no need for run dependency, this is async but will not do any prepare etc. step */ );
+  },
+
   emscripten_async_prepare: function(file, onload, onerror) {
     var _file = Pointer_stringify(file);
     var data = FS.analyzePath(_file);

system/include/emscripten/emscripten.h

@@ -186,6 +186,30 @@ float emscripten_random();
  */
 void emscripten_async_wget(const char* url, const char* file, void (*onload)(const char*), void (*onerror)(const char*));
 
+/*
+ * Data version of emscripten_async_wget. Instead of writing
+ * to a file, it writes to a buffer directly in memory.
+ * This avoids the overhead of using the emulated
+ * filesystem, note however that since files are not used,
+ * It cannot do the 'prepare' stage to set things up for
+ * IMG_Load and so forth (IMG_Load etc. work on files).
+ *
+ * @param arg User-defined data that is passed to the callbacks,
+ *
+ * @param onload Callback on success, with the @arg that
+ *               was provided to this function, a pointer
+ *               to a buffer with the data, and the size
+ *               of the buffer. As in the worker API, the
+ *               data buffer only lives during the
+ *               callback, so you should use it or copy
+ *               it during that time and not later.
+ *
+ * @param onerror An optional callback on failure, with the
+ *                @arg that was provided to this function.
+ *
+ */
+void emscripten_async_wget_data(const char* url, void *arg, void (*onload)(void*, void*, int), void (*onerror)(void*));
+
 /*
  * Prepare a file in asynchronous way. This does just the
  * preparation part of emscripten_async_wget, that is, it

tests/emscripten_fs_api_browser.cpp

@@ -9,10 +9,42 @@ extern "C" {
 
 int result = 1;
 int get_count = 0;
+int data_ok = 0;
+int data_bad = 0;
+
+void onLoadedData(void *arg, void *buffer, int size) {
+  get_count++;
+  assert(size == 329895);
+  assert((int)arg == 135);
+  unsigned char *b = (unsigned char*)buffer;
+  assert(b[0] == 137);
+  assert(b[1122] == 128);
+  assert(b[1123] == 201);
+  assert(b[202125] == 218);
+  data_ok = 1;
+}
+
+void onErrorData(void *arg) {
+  get_count++;
+  assert((int)arg == 246);
+  data_bad = 1;
+}
 
 void wait_wgets() {
   if (get_count == 3) {
+    emscripten_async_wget_data(
+      "http://localhost:8888/screenshot.png",
+      (void*)135,
+      onLoadedData,
+      onErrorData);
+    emscripten_async_wget_data(
+      "http://localhost:8888/fail_me",
+      (void*)246,
+      onLoadedData,
+      onErrorData);
+  } else if (get_count == 5) {
     assert(IMG_Load("/tmp/screen_shot.png"));
+    assert(data_ok == 1 && data_bad == 1);
     emscripten_cancel_main_loop();
     REPORT_RESULT();
   }