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      1 // Copyright (c) 2012 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/browser/renderer_host/java/java_bridge_dispatcher_host.h"
      6 
      7 #include "base/android/java_handler_thread.h"
      8 #include "base/bind.h"
      9 #include "base/lazy_instance.h"
     10 #include "content/browser/renderer_host/java/java_bridge_channel_host.h"
     11 #include "content/browser/renderer_host/render_view_host_impl.h"
     12 #include "content/child/child_process.h"
     13 #include "content/child/npapi/npobject_stub.h"
     14 #include "content/child/npapi/npobject_util.h"  // For CreateNPVariantParam()
     15 #include "content/common/java_bridge_messages.h"
     16 #include "content/public/browser/browser_thread.h"
     17 #include "content/public/browser/render_process_host.h"
     18 #include "third_party/WebKit/public/web/WebBindings.h"
     19 
     20 #if !defined(OS_ANDROID)
     21 #error "JavaBridge only supports OS_ANDROID"
     22 #endif
     23 
     24 namespace content {
     25 
     26 namespace {
     27 // The JavaBridge needs to use a Java thread so the callback
     28 // will happen on a thread with a prepared Looper.
     29 class JavaBridgeThread : public base::android::JavaHandlerThread {
     30  public:
     31   JavaBridgeThread() : base::android::JavaHandlerThread("JavaBridge") {
     32     Start();
     33   }
     34   virtual ~JavaBridgeThread() {
     35     Stop();
     36   }
     37 };
     38 
     39 void CleanUpStubs(const std::vector<base::WeakPtr<NPObjectStub> > & stubs) {
     40   for (size_t i = 0; i < stubs.size(); ++i) {
     41     if (stubs[i]) {
     42       stubs[i]->DeleteSoon();
     43     }
     44   }
     45 }
     46 
     47 base::LazyInstance<JavaBridgeThread> g_background_thread =
     48     LAZY_INSTANCE_INITIALIZER;
     49 }  // namespace
     50 
     51 JavaBridgeDispatcherHost::JavaBridgeDispatcherHost(
     52     RenderViewHost* render_view_host)
     53     : render_view_host_(render_view_host) {
     54 }
     55 
     56 JavaBridgeDispatcherHost::~JavaBridgeDispatcherHost() {
     57   g_background_thread.Get().message_loop()->PostTask(
     58       FROM_HERE,
     59       base::Bind(&CleanUpStubs, stubs_));
     60 }
     61 
     62 void JavaBridgeDispatcherHost::AddNamedObject(const base::string16& name,
     63                                               NPObject* object) {
     64   NPVariant_Param variant_param;
     65   CreateNPVariantParam(object, &variant_param);
     66 
     67   Send(new JavaBridgeMsg_AddNamedObject(
     68       render_view_host_->GetRoutingID(), name, variant_param));
     69 }
     70 
     71 void JavaBridgeDispatcherHost::RemoveNamedObject(const base::string16& name) {
     72   // On receipt of this message, the JavaBridgeDispatcher will drop its
     73   // reference to the corresponding proxy object. When the last reference is
     74   // removed, the proxy object will delete its NPObjectProxy, which will cause
     75   // the NPObjectStub to be deleted, which will drop its reference to the
     76   // original NPObject.
     77   Send(new JavaBridgeMsg_RemoveNamedObject(
     78       render_view_host_->GetRoutingID(), name));
     79 }
     80 
     81 void JavaBridgeDispatcherHost::RenderViewDeleted() {
     82   render_view_host_ = NULL;
     83 }
     84 
     85 void JavaBridgeDispatcherHost::OnGetChannelHandle(IPC::Message* reply_msg) {
     86   g_background_thread.Get().message_loop()->PostTask(
     87       FROM_HERE,
     88       base::Bind(&JavaBridgeDispatcherHost::GetChannelHandle, this, reply_msg));
     89 }
     90 
     91 void JavaBridgeDispatcherHost::Send(IPC::Message* msg) {
     92   if (render_view_host_) {
     93     render_view_host_->Send(msg);
     94     return;
     95   }
     96 
     97   delete msg;
     98 }
     99 
    100 void JavaBridgeDispatcherHost::GetChannelHandle(IPC::Message* reply_msg) {
    101   // The channel creates the channel handle based on the renderer ID we passed
    102   // to GetJavaBridgeChannelHost() and, on POSIX, the file descriptor used by
    103   // the underlying channel.
    104   JavaBridgeHostMsg_GetChannelHandle::WriteReplyParams(
    105       reply_msg,
    106       channel_->channel_handle());
    107 
    108   BrowserThread::PostTask(
    109       BrowserThread::UI,
    110       FROM_HERE,
    111       base::Bind(&JavaBridgeDispatcherHost::Send, this, reply_msg));
    112 }
    113 
    114 void JavaBridgeDispatcherHost::CreateNPVariantParam(NPObject* object,
    115                                                     NPVariant_Param* param) {
    116   // The JavaBridgeChannelHost needs to be created on the background thread, as
    117   // that is where Java objects will live, and CreateNPVariantParam() needs the
    118   // channel to create the NPObjectStub. To avoid blocking here until the
    119   // channel is ready, create the NPVariant_Param by hand, then post a message
    120   // to the background thread to set up the channel and create the corresponding
    121   // NPObjectStub. Post that message before doing any IPC, to make sure that
    122   // the channel and object proxies are ready before responses are received
    123   // from the renderer.
    124 
    125   // Create an NPVariantParam suitable for serialization over IPC from our
    126   // NPVariant. See CreateNPVariantParam() in npobject_utils.
    127   param->type = NPVARIANT_PARAM_SENDER_OBJECT_ROUTING_ID;
    128   int route_id = JavaBridgeChannelHost::ThreadsafeGenerateRouteID();
    129   param->npobject_routing_id = route_id;
    130 
    131   blink::WebBindings::retainObject(object);
    132   g_background_thread.Get().message_loop()->PostTask(
    133       FROM_HERE,
    134       base::Bind(&JavaBridgeDispatcherHost::CreateObjectStub, this, object,
    135                  render_view_host_->GetProcess()->GetID(), route_id));
    136 }
    137 
    138 void JavaBridgeDispatcherHost::CreateObjectStub(NPObject* object,
    139                                                 int render_process_id,
    140                                                 int route_id) {
    141   DCHECK_EQ(g_background_thread.Get().message_loop(),
    142             base::MessageLoop::current());
    143   if (!channel_.get()) {
    144     channel_ = JavaBridgeChannelHost::GetJavaBridgeChannelHost(
    145         render_process_id,
    146         BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
    147   }
    148 
    149   // In a typical scenario, the lifetime of each NPObjectStub is governed by
    150   // that of the NPObjectProxy in the renderer, via the channel. However,
    151   // we cannot guaranteed that the renderer always terminates cleanly
    152   // (crashes / sometimes just unavoidable). We keep a weak reference to
    153   // it now and schedule a delete on it when this host is getting deleted.
    154 
    155   // Pass 0 for the containing window, as it's only used by plugins to pump the
    156   // window message queue when a method on a renderer-side object causes a
    157   // dialog to be displayed, and the Java Bridge does not need this
    158   // functionality. The page URL is also not required.
    159   stubs_.push_back((new NPObjectStub(
    160       object, channel_.get(), route_id, 0, GURL()))->AsWeakPtr());
    161 
    162   // The NPObjectStub takes a reference to the NPObject. Release the ref added
    163   // in CreateNPVariantParam().
    164   blink::WebBindings::releaseObject(object);
    165 }
    166 
    167 }  // namespace content
    168