FS.createPreloadedFile

4 files changed, 31 insertions, 1 deletions

diff --git a/src/jsifier.js b/src/jsifier.js
index 77d67bec..89930918 100644
--- a/src/jsifier.js
+++ b/src/jsifier.js
@@ -73,6 +73,9 @@ function JSify(data, functionsOnly, givenFunctions) {
     } else {
       libFuncsToInclude = ['memcpy', 'memset', 'malloc', 'free'];
     }
+    if (GENERATING_HTML) {
+      libFuncsToInclude.push('$Browser');
+    }
     libFuncsToInclude.forEach(function(ident) {
       data.functionStubs.push({
         intertype: 'functionStub',
diff --git a/src/library.js b/src/library.js
index bac57b59..7e39bdca 100644
--- a/src/library.js
+++ b/src/library.js
@@ -257,11 +257,20 @@ LibraryManager.library = {
       var properties = {isDevice: false, contents: data};
       return FS.createFile(parent, name, properties, canRead, canWrite);
     },
-    // Creates a file record for lazy-loading from a URL.
+    // Creates a file record for lazy-loading from a URL. XXX This requires a synchronous
+    // XHR, which is not possible in browsers except in a web worker! Use preloading,
+    // either --preload-file in emcc or FS.createPreloadedFile
     createLazyFile: function(parent, name, url, canRead, canWrite) {
       var properties = {isDevice: false, url: url};
       return FS.createFile(parent, name, properties, canRead, canWrite);
     },
+    // Preloads a file asynchronously. You can call this before run, for example in
+    // preRun. run will be delayed until this file arrives and is set up.
+    createPreloadedFile: function(parent, name, url, canRead, canWrite) {
+      Browser.asyncLoad(url, function(data) {
+        FS.createDataFile(parent, name, data, canRead, canWrite);
+      });
+    },
     // Creates a link to a sepcific local path.
     createLink: function(parent, name, target, canRead, canWrite) {
       var properties = {isDevice: false, link: target};
diff --git a/src/library_browser.js b/src/library_browser.js
index eb7f0293..6b2dfeff 100644
--- a/src/library_browser.js
+++ b/src/library_browser.js
@@ -138,6 +138,22 @@ mergeInto(LibraryManager.library, {
              0; // delta;
     },
 
+    asyncLoad: function(url, callback) {
+      var xhr = new XMLHttpRequest();
+      xhr.open('GET', url, true);
+      xhr.responseType = 'arraybuffer';
+      xhr.onload = function() {
+        var arrayBuffer = xhr.response;
+        assert(arrayBuffer, 'Loading data file "' + url + '" failed (no arrayBuffer).');
+        callback(new Uint8Array(arrayBuffer));
+        removeRunDependency();
+      };
+      xhr.onerror = function(event) {
+        assert(arrayBuffer, 'Loading data file "' + url + '" failed.');
+      };
+      xhr.send(null);
+      addRunDependency();
+    }
   },
 
   emscripten_async_run_script__deps: ['emscripten_run_script'],
diff --git a/src/settings.js b/src/settings.js
index 452472d9..881f7b17 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -205,6 +205,8 @@ var LINKABLE = 0; // If set to 1, this file can be linked with others, either as
                   // LINKABLE of 0 is very useful in that we can reduce the size of the
                   // generated code very significantly, by removing everything not actually used.
 
+var GENERATING_HTML = 0; // Set to 1 when generating .html and not just .js
+
 var RUNTIME_TYPE_INFO = 0; // Whether to expose type info to the script at run time. This
                            // increases the size of the generated script, but allows you
                            // to more easily perform operations from handwritten JS on