Refactor renderer-side script injection

extensions/renderer/user_script_injection_list.cc

+// Copyright 2014 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 "extensions/renderer/user_script_injection_list.h"
+
+#include "content/public/common/url_constants.h"
+#include "content/public/renderer/render_thread.h"
+#include "extensions/common/extension.h"
+#include "extensions/common/extension_messages.h"
+#include "extensions/common/extension_set.h"
+#include "extensions/common/permissions/permissions_data.h"
+#include "extensions/renderer/extensions_renderer_client.h"
+#include "extensions/renderer/script_context.h"
+#include "extensions/renderer/user_script_injection.h"
+#include "third_party/WebKit/public/web/WebDocument.h"
+#include "third_party/WebKit/public/web/WebFrame.h"
+#include "url/gurl.h"
+
+namespace extensions {
+
+// static
+GURL UserScriptInjectionList::GetDocumentUrlForFrame(blink::WebFrame* frame) {
+  GURL data_source_url = ScriptContext::GetDataSourceURLForFrame(frame);
+  if (!data_source_url.is_empty() && frame->isViewSourceModeEnabled()) {
+    data_source_url = GURL(content::kViewSourceScheme + std::string(":") +
+                           data_source_url.spec());
+  }
+
+  return data_source_url;
+}
+
+UserScriptInjectionList::UserScriptInjectionList() {
+  content::RenderThread::Get()->AddObserver(this);
+}
+
+UserScriptInjectionList::~UserScriptInjectionList() {
+}
+
+void UserScriptInjectionList::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void UserScriptInjectionList::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+void UserScriptInjectionList::GetActiveExtensionIds(
+    std::set<std::string>* ids) const {
+  for (ScopedVector<UserScript>::const_iterator iter = scripts_.begin();
+       iter != scripts_.end();
+       ++iter) {
+    DCHECK(!(*iter)->extension_id().empty());
+    ids->insert((*iter)->extension_id());
+  }
+}
+
+void UserScriptInjectionList::GetInjections(
+    ScopedVector<ScriptInjection>* injections,
+    blink::WebFrame* web_frame,
+    int tab_id,
+    UserScript::RunLocation run_location,
+    const GURL& document_url,
+    const ExtensionSet* extensions) {
+  for (ScopedVector<UserScript>::const_iterator iter = scripts_.begin();
+       iter != scripts_.end();
+       ++iter) {
+    const Extension* extension = extensions->GetByID((*iter)->extension_id());
+    if (!extension)
+      continue;
+    scoped_ptr<ScriptInjection> injection = GetInjectionForScript(
+        *iter, web_frame, tab_id, run_location, document_url, extension);
+    if (injection.get())
+      injections->push_back(injection.release());
+  }
+}
+
+bool UserScriptInjectionList::OnControlMessageReceived(
+    const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(UserScriptInjectionList, message)
+    IPC_MESSAGE_HANDLER(ExtensionMsg_UpdateUserScripts, OnUpdateUserScripts)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void UserScriptInjectionList::OnUpdateUserScripts(
+    base::SharedMemoryHandle shared_memory,
+    const std::set<std::string>& changed_extensions) {
+  if (!base::SharedMemory::IsHandleValid(shared_memory)) {
+    NOTREACHED() << "Bad scripts handle";
+    return;
+  }
+
+  for (std::set<std::string>::const_iterator iter = changed_extensions.begin();
+       iter != changed_extensions.end();
+       ++iter) {
+    if (!Extension::IdIsValid(*iter)) {
+      NOTREACHED() << "Invalid extension id: " << *iter;
+      return;
+    }
+  }
+
+  if (UpdateScripts(shared_memory)) {
+    FOR_EACH_OBSERVER(Observer,
+                      observers_,
+                      OnUserScriptsUpdated(changed_extensions, scripts_.get()));
+  }
+}
+
+bool UserScriptInjectionList::UpdateScripts(
+    base::SharedMemoryHandle shared_memory) {
+  bool only_inject_incognito =
+      ExtensionsRendererClient::Get()->IsIncognitoProcess();
+
+  // Create the shared memory object (read only).
+  shared_memory_.reset(new base::SharedMemory(shared_memory, true));
+  if (!shared_memory_.get())
+    return false;
+
+  // First get the size of the memory block.
+  if (!shared_memory_->Map(sizeof(Pickle::Header)))
+    return false;
+  Pickle::Header* pickle_header =
+      reinterpret_cast<Pickle::Header*>(shared_memory_->memory());
+
+  // Now map in the rest of the block.
+  int pickle_size = sizeof(Pickle::Header) + pickle_header->payload_size;
+  shared_memory_->Unmap();
+  if (!shared_memory_->Map(pickle_size))
+    return false;
+
+  // Unpickle scripts.
+  uint64 num_scripts = 0;
+  Pickle pickle(reinterpret_cast<char*>(shared_memory_->memory()), pickle_size);
+  PickleIterator iter(pickle);
+  CHECK(pickle.ReadUInt64(&iter, &num_scripts));
+
+  scripts_.clear();
+  scripts_.reserve(num_scripts);
+  for (uint64 i = 0; i < num_scripts; ++i) {
+    scoped_ptr<UserScript> script(new UserScript());
+    script->Unpickle(pickle, &iter);
+
+    // Note that this is a pointer into shared memory. We don't own it. It gets
+    // cleared up when the last renderer or browser process drops their
+    // reference to the shared memory.
+    for (size_t j = 0; j < script->js_scripts().size(); ++j) {
+      const char* body = NULL;
+      int body_length = 0;
+      CHECK(pickle.ReadData(&iter, &body, &body_length));
+      script->js_scripts()[j].set_external_content(
+          base::StringPiece(body, body_length));
+    }
+    for (size_t j = 0; j < script->css_scripts().size(); ++j) {
+      const char* body = NULL;
+      int body_length = 0;
+      CHECK(pickle.ReadData(&iter, &body, &body_length));
+      script->css_scripts()[j].set_external_content(
+          base::StringPiece(body, body_length));
+    }
+
+    if (only_inject_incognito && !script->is_incognito_enabled())
+      continue;  // This script shouldn't run in an incognito tab.
+
+    scripts_.push_back(script.release());
+  }
+
+  return true;
+}

[not at google - send to devlin, 2014/06/15 23:53:38]

blank line

[Devlin, 2014/06/16 18:11:17]

Done.

+scoped_ptr<ScriptInjection> UserScriptInjectionList::GetInjectionForScript(
+    UserScript* script,
+    blink::WebFrame* web_frame,
+    int tab_id,
+    UserScript::RunLocation run_location,
+    const GURL& document_url,
+    const Extension* extension) {
+  scoped_ptr<ScriptInjection> injection;
+  if (web_frame->parent() && !script->match_all_frames())
+    return injection.Pass();  // Only match subframes if the script declared it.
+
+  // Content scripts are not tab-specific.
+  static const int kNoTabId = -1;
+  // We don't have a process id in this context.
+  static const int kNoProcessId = -1;
+
+  GURL effective_document_url = ScriptContext::GetEffectiveDocumentURL(
+      web_frame, document_url, script->match_about_blank());
+
+  if (!script->MatchesURL(effective_document_url))
+    return injection.Pass();
+
+  if (!extension->permissions_data()->CanRunContentScriptOnPage(
+          extension,
+          effective_document_url,
+          web_frame->top()->document().url(),
+          kNoTabId,
+          kNoProcessId,

[not at google - send to devlin, 2014/06/15 23:53:38]

inling -1 with those comments "Content scripts are not tab-specific" etc is
cleaner IMO than having kNoTabId constants.

[Devlin, 2014/06/16 18:11:17]

Done.

+          NULL /* ignore error */)) {
+    return injection.Pass();
+  }
+
+  bool inject_css = !script->css_scripts().empty() &&
+                    run_location == UserScript::DOCUMENT_START;
+  bool inject_js =
+      !script->js_scripts().empty() && script->run_location() == run_location;

[not at google - send to devlin, 2014/06/15 23:53:38]

this mixing of UserScriptInjection getting its properties either passed in or
read off its UserScript, and/or then caching some of the values, is a little
confusing.
- I wouldn't bother passing in inject_js and inject_css. UserScriptInjection can
calculate "script_->js_scripts().empty()" just fine, likewise css.
- I also just wouldn't bother caching anything you can read straight off
script_, like the script ID.

[Devlin, 2014/06/16 18:11:17]

Caching script id is done because when we need to update the script, we don't
want to read the id from the now-dangerously-possibly-deleted script object. 
Added a comment to make that clear.

+  if (inject_css || inject_js) {
+    injection.reset(new UserScriptInjection(web_frame,
+                                            extension->id(),
+                                            run_location,
+                                            tab_id,
+                                            this,
+                                            script,
+                                            inject_js,
+                                            inject_css));
+  }
+  return injection.Pass();
+}
+
+}  // namespace extensions