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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "content/renderer/web_ui_mojo_context_state.h"
      6 
      7 #include "base/bind.h"
      8 #include "base/stl_util.h"
      9 #include "content/public/renderer/resource_fetcher.h"
     10 #include "content/renderer/web_ui_runner.h"
     11 #include "gin/converter.h"
     12 #include "gin/modules/module_registry.h"
     13 #include "gin/per_context_data.h"
     14 #include "gin/public/context_holder.h"
     15 #include "gin/try_catch.h"
     16 #include "mojo/bindings/js/core.h"
     17 #include "mojo/bindings/js/handle.h"
     18 #include "mojo/bindings/js/support.h"
     19 #include "third_party/WebKit/public/platform/WebURLResponse.h"
     20 #include "third_party/WebKit/public/web/WebFrame.h"
     21 #include "third_party/WebKit/public/web/WebScriptSource.h"
     22 
     23 using v8::Context;
     24 using v8::HandleScope;
     25 using v8::Isolate;
     26 using v8::Object;
     27 using v8::ObjectTemplate;
     28 using v8::Script;
     29 
     30 namespace content {
     31 
     32 namespace {
     33 
     34 // All modules have this prefixed to them when downloading.
     35 // TODO(sky): move this into some common place.
     36 const char kModulePrefix[] = "chrome://mojo/";
     37 
     38 void RunMain(base::WeakPtr<gin::Runner> runner,
     39              v8::Handle<v8::Value> module) {
     40   v8::Isolate* isolate = runner->GetContextHolder()->isolate();
     41   v8::Handle<v8::Function> start;
     42   CHECK(gin::ConvertFromV8(isolate, module, &start));
     43   runner->Call(start, runner->global(), 0, NULL);
     44 }
     45 
     46 }  // namespace
     47 
     48 // WebUIMojo -------------------------------------------------------------------
     49 
     50 WebUIMojoContextState::WebUIMojoContextState(blink::WebFrame* frame,
     51                                              v8::Handle<v8::Context> context)
     52     : frame_(frame),
     53       module_added_(false) {
     54   gin::PerContextData* context_data = gin::PerContextData::From(context);
     55   gin::ContextHolder* context_holder = context_data->context_holder();
     56   runner_.reset(new WebUIRunner(frame_, context_holder));
     57   gin::Runner::Scope scoper(runner_.get());
     58   gin::ModuleRegistry::From(context)->AddObserver(this);
     59   runner_->RegisterBuiltinModules();
     60   gin::ModuleRegistry::InstallGlobals(context->GetIsolate(), context->Global());
     61   // Warning |frame| may be destroyed.
     62   // TODO(sky): add test for this.
     63 }
     64 
     65 WebUIMojoContextState::~WebUIMojoContextState() {
     66   gin::Runner::Scope scoper(runner_.get());
     67   gin::ModuleRegistry::From(
     68       runner_->GetContextHolder()->context())->RemoveObserver(this);
     69 }
     70 
     71 void WebUIMojoContextState::Run() {
     72   gin::ContextHolder* context_holder = runner_->GetContextHolder();
     73   gin::ModuleRegistry::From(context_holder->context())->LoadModule(
     74       context_holder->isolate(),
     75       "main",
     76       base::Bind(RunMain, runner_->GetWeakPtr()));
     77 }
     78 
     79 void WebUIMojoContextState::FetchModules(const std::vector<std::string>& ids) {
     80   gin::Runner::Scope scoper(runner_.get());
     81   gin::ContextHolder* context_holder = runner_->GetContextHolder();
     82   gin::ModuleRegistry* registry = gin::ModuleRegistry::From(
     83       context_holder->context());
     84   for (size_t i = 0; i < ids.size(); ++i) {
     85     if (fetched_modules_.find(ids[i]) == fetched_modules_.end() &&
     86         registry->available_modules().count(ids[i]) == 0) {
     87       FetchModule(ids[i]);
     88     }
     89   }
     90 }
     91 
     92 void WebUIMojoContextState::FetchModule(const std::string& id) {
     93   const GURL url(kModulePrefix + id);
     94   // TODO(sky): better error checks here?
     95   DCHECK(url.is_valid() && !url.is_empty());
     96   DCHECK(fetched_modules_.find(id) == fetched_modules_.end());
     97   fetched_modules_.insert(id);
     98   ResourceFetcher* fetcher = ResourceFetcher::Create(url);
     99   module_fetchers_.push_back(fetcher);
    100   fetcher->Start(frame_,
    101                  blink::WebURLRequest::RequestContextScript,
    102                  blink::WebURLRequest::FrameTypeNone,
    103                  ResourceFetcher::PLATFORM_LOADER,
    104                  base::Bind(&WebUIMojoContextState::OnFetchModuleComplete,
    105                             base::Unretained(this),
    106                             fetcher));
    107 }
    108 
    109 void WebUIMojoContextState::OnFetchModuleComplete(
    110     ResourceFetcher* fetcher,
    111     const blink::WebURLResponse& response,
    112     const std::string& data) {
    113   DCHECK_EQ(kModulePrefix,
    114       response.url().string().utf8().substr(0, arraysize(kModulePrefix) - 1));
    115   const std::string module =
    116       response.url().string().utf8().substr(arraysize(kModulePrefix) - 1);
    117   // We can't delete fetch right now as the arguments to this function come from
    118   // it and are used below. Instead use a scope_ptr to cleanup.
    119   scoped_ptr<ResourceFetcher> deleter(fetcher);
    120   module_fetchers_.weak_erase(
    121       std::find(module_fetchers_.begin(), module_fetchers_.end(), fetcher));
    122   if (data.empty()) {
    123     NOTREACHED();
    124     return;  // TODO(sky): log something?
    125   }
    126 
    127   runner_->Run(data, module);
    128 }
    129 
    130 void WebUIMojoContextState::OnDidAddPendingModule(
    131     const std::string& id,
    132     const std::vector<std::string>& dependencies) {
    133   FetchModules(dependencies);
    134 
    135   gin::ContextHolder* context_holder = runner_->GetContextHolder();
    136   gin::ModuleRegistry* registry = gin::ModuleRegistry::From(
    137       context_holder->context());
    138   registry->AttemptToLoadMoreModules(context_holder->isolate());
    139 }
    140 
    141 }  // namespace content
    142