Mojo: Log an error when we fail to find a JS module.

gin/modules/file_module_provider.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gin/modules/file_module_provider.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_split.h"
 #include "gin/converter.h"
 
 namespace gin {
 
 namespace {
 
-void AttempToLoadModule(const base::WeakPtr<Runner>& runner,
-                        const std::vector<base::FilePath>& search_paths,
-                        const std::string& id) {
-  if (!runner)
+void AttemptToLoadModule(const base::WeakPtr<Runner>& runner,
+                         const std::vector<base::FilePath>& search_paths,
+                         const std::string& id,
+                         base::Callback<void(bool)> callback) {
+  if (!runner) {
+    callback.Run(false);
     return;
+  }
 
   std::vector<std::string> components;
   base::SplitString(id, '/', &components);
 
   base::FilePath path;
   for (size_t i = 0; i < components.size(); ++i) {
     // TODO(abarth): Technically the path components can be UTF-8. We don't
     // handle that case correctly yet.
     path = path.AppendASCII(components[i]);
   }
   path = path.AddExtension(FILE_PATH_LITERAL("js"));
 
   for (size_t i = 0; i < search_paths.size(); ++i) {
     std::string source;
     if (!ReadFileToString(search_paths[i].Append(path), &source))
       continue;
 
     Runner::Scope scope(runner.get());
     runner->Run(source, id);
+    callback.Run(true);
     return;
   }
+  callback.Run(false);

[abarth-chromium, 2014/07/22 22:16:15]

Maybe we should just log something at this point and not wait for the system to
stop churning?  We should probably be looking on disk last anyway.

[Matt Perry, 2014/07/22 22:24:40]

Huh.. I thought I tried that and it resulted in false positives. But it seems to
work. That's way simpler. I'll do that.

 }
 
 }  // namespace
 
 FileModuleProvider::FileModuleProvider(
     const std::vector<base::FilePath>& search_paths)
-    : search_paths_(search_paths) {
+    : weak_factory_(this), search_paths_(search_paths) {
 }
 
 FileModuleProvider::~FileModuleProvider() {
 }
 
-void FileModuleProvider::AttempToLoadModules(
+void FileModuleProvider::AttemptToLoadModules(
     Runner* runner, const std::set<std::string>& ids) {
   std::set<std::string> modules = ids;
   for (std::set<std::string>::const_iterator it = modules.begin();
        it != modules.end(); ++it) {
     const std::string& id = *it;
     if (attempted_ids_.count(id))
       continue;
     attempted_ids_.insert(id);
     base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
-        AttempToLoadModule, runner->GetWeakPtr(), search_paths_, id));
+        AttemptToLoadModule, runner->GetWeakPtr(), search_paths_, id,
+        base::Bind(&FileModuleProvider::OnReadCompleted,
+                   weak_factory_.GetWeakPtr(), id)));
   }
 }
 
+void FileModuleProvider::OnReadCompleted(const std::string& id, bool success) {
+  if (success) {
+    successful_ids_.insert(id);
+  } else {
+    failed_ids_.insert(id);
+  }
+
+  if (failed_ids_.size() + successful_ids_.size() == attempted_ids_.size()) {
+    if (!completion_callback_.is_null())
+      completion_callback_.Run(successful_ids_);
+  }
+}
+
 }  // namespace gin