Introduce HostID and de-couple Extensions from "script injection System" [browser side]

chrome/browser/extensions/extension_user_script_loader.cc

+// Copyright 2015 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 "chrome/browser/extensions/extension_user_script_loader.h"
+
+#include <set>
+#include <string>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/version.h"
+#include "chrome/browser/chrome_notification_types.h"

[Devlin, 2015/01/20 17:51:05]

nit: prune includes.

[Xi Han, 2015/01/21 21:30:16]

Why I cannot find these unnecessary includes:(

+#include "chrome/browser/profiles/profile.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/render_process_host.h"
+#include "extensions/browser/component_extension_resource_manager.h"
+#include "extensions/browser/content_verifier.h"
+#include "extensions/browser/extension_registry.h"
+#include "extensions/browser/extension_system.h"
+#include "extensions/browser/extensions_browser_client.h"
+#include "extensions/common/extension_messages.h"
+#include "extensions/common/file_util.h"
+#include "extensions/common/manifest_handlers/default_locale_handler.h"
+#include "extensions/common/message_bundle.h"
+#include "extensions/common/one_shot_event.h"
+#include "ui/base/resource/resource_bundle.h"
+
+using content::BrowserThread;

[Devlin, 2015/01/20 17:51:05]

nit: Even though you have this line, you specify "content::BrowserThread"
everywhere.  Just delete this one (we have a slight preference for not using too
many usings, anyway).

[Xi Han, 2015/01/21 21:30:16]

Removed.

+
+namespace extensions {
+
+namespace {
+
+// Verifies file contents as they are read.
+void VerifyContent(scoped_refptr<ContentVerifier> verifier,
+                   const ConsumerID& consumer_id,
+                   const base::FilePath& extension_root,
+                   const base::FilePath& relative_path,
+                   const std::string& content) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  scoped_refptr<ContentVerifyJob> job(verifier->CreateJobFor(
+      consumer_id.host_id(), extension_root, relative_path));

[Devlin, 2015/01/20 17:51:05]

nit: since this is in the ExtensionUserScriptLoader, we can probably just pass
this function the extension id, instead of the full consumer id.

[Xi Han, 2015/01/21 21:30:16]

Done.

+  if (job.get()) {
+    job->Start();
+    job->BytesRead(content.size(), content.data());
+    job->DoneReading();
+  }
+}
+
+}  // namespace
+
+ExtensionUserScriptLoader::ExtensionUserScriptLoader(
+    Profile* profile,
+    const ConsumerID& consumer_id,
+    bool listen_for_extension_system_loaded)
+    : UserScriptLoader(profile,
+                       consumer_id,
+                       ExtensionSystem::Get(profile)->content_verifier()),
+      extension_registry_observer_(this),
+      weak_factory_(this) {
+  extension_registry_observer_.Add(ExtensionRegistry::Get(profile));
+  if (listen_for_extension_system_loaded) {
+    SetReady(false);

[Devlin, 2015/01/20 17:51:05]

UserScriptLoader is, by default, set to false.  You can take out this line.

[Xi Han, 2015/01/21 21:30:16]

Done.

+    ExtensionSystem::Get(profile)->ready().Post(
+        FROM_HERE,
+        base::Bind(&ExtensionUserScriptLoader::OnExtensionSystemReady,
+                   weak_factory_.GetWeakPtr()));
+  } else {
+    SetReady(true);
+  }
+}
+
+ExtensionUserScriptLoader::~ExtensionUserScriptLoader() {
+}
+
+void ExtensionUserScriptLoader::UpdateConsumersInfo(
+    const ConsumerIDSet& changed_consumers) {
+  ExtensionRegistry* registry = ExtensionRegistry::Get(profile());
+  for (const ConsumerID& consumer_id : changed_consumers) {
+    const Extension* extension = registry->GetExtensionById(
+        consumer_id.host_id(), ExtensionRegistry::ENABLED);
+    // |changed_consumers_| may include consumers that have been removed,
+    // which leads to the above lookup failing. In this case, just continue.
+    if (!extension)
+      continue;
+    AddConsumerInfo(consumer_id, ExtensionSet::ExtensionPathAndDefaultLocale(
+                                     extension->path(),
+                                     LocaleInfo::GetDefaultLocale(extension)));
+  }
+}
+
+void ExtensionUserScriptLoader::SendUpdate(
+    content::RenderProcessHost* process,
+    base::SharedMemoryHandle handle_for_process,
+    const std::set<ConsumerID>& changed_consumers) {
+  // TODO(hanxi): update the IPC message to send a set of ConsumerID to render.
+  // Also, remove this function when the refactor is done on render side.
+  std::set<std::string> changed_extensions;
+  for (std::set<ConsumerID>::iterator it = changed_consumers.begin();

[Devlin, 2015/01/20 17:51:05]

nit: shorter:
for (const ConsumerID& id : changed_consumers)
  changed_extensions.insert(id.host_id());

[Xi Han, 2015/01/21 21:30:16]

Done.

+       it != changed_consumers.end(); ++it) {
+    changed_extensions.insert(it->host_id());
+  }
+
+  if (base::SharedMemory::IsHandleValid(handle_for_process)) {
+    process->Send(new ExtensionMsg_UpdateUserScripts(
+        handle_for_process, consumer_id().host_id(), changed_extensions));
+  }
+}
+
+UserScriptLoader::LoadUserScriptsFunctionCallback
+ExtensionUserScriptLoader::GetLoadUserScriptsFunction() {
+  return base::Bind(&ExtensionUserScriptLoader::LoadScriptContent);
+}
+
+// static
+bool ExtensionUserScriptLoader::LoadScriptContent(
+    const ConsumerID& consumer_id,
+    UserScript::File* script_file,
+    const SubstitutionMap* localization_messages,
+    scoped_refptr<ContentVerifier> verifier) {
+  DCHECK(script_file);
+  std::string content;
+  const base::FilePath& path = ExtensionResource::GetFilePath(
+      script_file->extension_root(), script_file->relative_path(),
+      ExtensionResource::SYMLINKS_MUST_RESOLVE_WITHIN_ROOT);
+  if (path.empty()) {
+    int resource_id = 0;
+    if (ExtensionsBrowserClient::Get()
+            ->GetComponentExtensionResourceManager()
+            ->IsComponentExtensionResource(script_file->extension_root(),
+                                           script_file->relative_path(),
+                                           &resource_id)) {
+      const ResourceBundle& rb = ResourceBundle::GetSharedInstance();
+      content = rb.GetRawDataResource(resource_id).as_string();
+    } else {
+      LOG(WARNING) << "Failed to get file path to "
+                   << script_file->relative_path().value() << " from "
+                   << script_file->extension_root().value();
+      return false;
+    }
+  } else {
+    if (!base::ReadFileToString(path, &content)) {
+      LOG(WARNING) << "Failed to load user script file: " << path.value();
+      return false;
+    }
+    if (verifier.get()) {
+      content::BrowserThread::PostTask(
+          content::BrowserThread::IO, FROM_HERE,
+          base::Bind(&VerifyContent, verifier, consumer_id,
+                     script_file->extension_root(),
+                     script_file->relative_path(), content));
+    }
+  }
+
+  // Localize the content.
+  if (localization_messages) {
+    std::string error;
+    MessageBundle::ReplaceMessagesWithExternalDictionary(*localization_messages,
+                                                         &content, &error);
+    if (!error.empty())
+      LOG(WARNING) << "Failed to replace messages in script: " << error;
+  }
+
+  // Remove BOM from the content.
+  std::string::size_type index = content.find(base::kUtf8ByteOrderMark);
+  if (index == 0) {

[Devlin, 2015/01/20 17:51:05]

nit: no brackets.

[Xi Han, 2015/01/21 21:30:16]

Done.

+    script_file->set_content(content.substr(strlen(base::kUtf8ByteOrderMark)));
+  } else {
+    script_file->set_content(content);
+  }
+
+  return true;
+}
+
+void ExtensionUserScriptLoader::OnExtensionUnloaded(
+    content::BrowserContext* browser_context,
+    const Extension* extension,
+    UnloadedExtensionInfo::Reason reason) {
+  RemoveConsumerInfo(extension->id());
+}
+
+void ExtensionUserScriptLoader::OnExtensionSystemReady() {
+  SetReady(true);
+}
+
+}  // namespace extensions