ppb_message_loop_proxy.cc revision 1320f92c476a1ad9d19dba2a48c72b75566198e9 
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 "ppapi/proxy/ppb_message_loop_proxy.h"
6
7#include <vector>
8
9#include "base/bind.h"
10#include "base/compiler_specific.h"
11#include "base/message_loop/message_loop.h"
12#include "base/message_loop/message_loop_proxy.h"
13#include "ppapi/c/pp_errors.h"
14#include "ppapi/c/ppb_message_loop.h"
15#include "ppapi/proxy/plugin_dispatcher.h"
16#include "ppapi/proxy/plugin_globals.h"
17#include "ppapi/shared_impl/proxy_lock.h"
18#include "ppapi/thunk/enter.h"
19
20using ppapi::thunk::PPB_MessageLoop_API;
21
22namespace ppapi {
23namespace proxy {
24
25namespace {
26typedef thunk::EnterResource<PPB_MessageLoop_API> EnterMessageLoop;
27}
28
29MessageLoopResource::MessageLoopResource(PP_Instance instance)
30    : MessageLoopShared(instance),
31      nested_invocations_(0),
32      destroyed_(false),
33      should_destroy_(false),
34      is_main_thread_loop_(false),
35      currently_handling_blocking_message_(false) {
36}
37
38MessageLoopResource::MessageLoopResource(ForMainThread for_main_thread)
39    : MessageLoopShared(for_main_thread),
40      nested_invocations_(0),
41      destroyed_(false),
42      should_destroy_(false),
43      is_main_thread_loop_(true),
44      currently_handling_blocking_message_(false) {
45  // We attach the main thread immediately. We can't use AttachToCurrentThread,
46  // because the MessageLoop already exists.
47
48  // This must be called only once, so the slot must be empty.
49  CHECK(!PluginGlobals::Get()->msg_loop_slot());
50  // We don't add a reference for TLS here, so we don't release it. Instead,
51  // this loop is owned by PluginGlobals. Contrast with AttachToCurrentThread
52  // where we register ReleaseMessageLoop with TLS and call AddRef.
53  base::ThreadLocalStorage::Slot* slot = new base::ThreadLocalStorage::Slot();
54  PluginGlobals::Get()->set_msg_loop_slot(slot);
55
56  slot->Set(this);
57
58  loop_proxy_ = base::MessageLoopProxy::current();
59}
60
61
62MessageLoopResource::~MessageLoopResource() {
63}
64
65PPB_MessageLoop_API* MessageLoopResource::AsPPB_MessageLoop_API() {
66  return this;
67}
68
69int32_t MessageLoopResource::AttachToCurrentThread() {
70  if (is_main_thread_loop_)
71    return PP_ERROR_INPROGRESS;
72
73  PluginGlobals* globals = PluginGlobals::Get();
74
75  base::ThreadLocalStorage::Slot* slot = globals->msg_loop_slot();
76  if (!slot) {
77    slot = new base::ThreadLocalStorage::Slot(&ReleaseMessageLoop);
78    globals->set_msg_loop_slot(slot);
79  } else {
80    if (slot->Get())
81      return PP_ERROR_INPROGRESS;
82  }
83  // TODO(dmichael) check that the current thread can support a message loop.
84
85  // Take a ref to the MessageLoop on behalf of the TLS. Note that this is an
86  // internal ref and not a plugin ref so the plugin can't accidentally
87  // release it. This is released by ReleaseMessageLoop().
88  AddRef();
89  slot->Set(this);
90
91  loop_.reset(new base::MessageLoop);
92  loop_proxy_ = base::MessageLoopProxy::current();
93
94  // Post all pending work to the message loop.
95  for (size_t i = 0; i < pending_tasks_.size(); i++) {
96    const TaskInfo& info = pending_tasks_[i];
97    PostClosure(info.from_here, info.closure, info.delay_ms);
98  }
99  pending_tasks_.clear();
100
101  return PP_OK;
102}
103
104int32_t MessageLoopResource::Run() {
105  if (!IsCurrent())
106    return PP_ERROR_WRONG_THREAD;
107  if (is_main_thread_loop_)
108    return PP_ERROR_INPROGRESS;
109
110  nested_invocations_++;
111  CallWhileUnlocked(
112      base::Bind(&base::MessageLoop::Run, base::Unretained(loop_.get())));
113  nested_invocations_--;
114
115  if (should_destroy_ && nested_invocations_ == 0) {
116    loop_proxy_ = NULL;
117    loop_.reset();
118    destroyed_ = true;
119  }
120  return PP_OK;
121}
122
123int32_t MessageLoopResource::PostWork(PP_CompletionCallback callback,
124                                      int64_t delay_ms) {
125  if (!callback.func)
126    return PP_ERROR_BADARGUMENT;
127  if (destroyed_)
128    return PP_ERROR_FAILED;
129  PostClosure(FROM_HERE,
130              base::Bind(callback.func, callback.user_data,
131                         static_cast<int32_t>(PP_OK)),
132              delay_ms);
133  return PP_OK;
134}
135
136int32_t MessageLoopResource::PostQuit(PP_Bool should_destroy) {
137  if (is_main_thread_loop_)
138    return PP_ERROR_WRONG_THREAD;
139
140  if (PP_ToBool(should_destroy))
141    should_destroy_ = true;
142
143  if (IsCurrent() && nested_invocations_ > 0)
144    loop_->Quit();
145  else
146    PostClosure(FROM_HERE, base::MessageLoop::QuitClosure(), 0);
147  return PP_OK;
148}
149
150// static
151MessageLoopResource* MessageLoopResource::GetCurrent() {
152  PluginGlobals* globals = PluginGlobals::Get();
153  if (!globals->msg_loop_slot())
154    return NULL;
155  return reinterpret_cast<MessageLoopResource*>(
156      globals->msg_loop_slot()->Get());
157}
158
159void MessageLoopResource::DetachFromThread() {
160  // Note that the message loop must be destroyed on the thread it was created
161  // on.
162  loop_proxy_ = NULL;
163  loop_.reset();
164
165  // Cancel out the AddRef in AttachToCurrentThread().
166  Release();
167  // DANGER: may delete this.
168}
169
170bool MessageLoopResource::IsCurrent() const {
171  PluginGlobals* globals = PluginGlobals::Get();
172  if (!globals->msg_loop_slot())
173    return false;  // Can't be current if there's nothing in the slot.
174  return static_cast<const void*>(globals->msg_loop_slot()->Get()) ==
175         static_cast<const void*>(this);
176}
177
178void MessageLoopResource::PostClosure(
179    const tracked_objects::Location& from_here,
180    const base::Closure& closure,
181    int64 delay_ms) {
182  if (loop_proxy_.get()) {
183    loop_proxy_->PostDelayedTask(
184        from_here, closure, base::TimeDelta::FromMilliseconds(delay_ms));
185  } else {
186    TaskInfo info;
187    info.from_here = FROM_HERE;
188    info.closure = closure;
189    info.delay_ms = delay_ms;
190    pending_tasks_.push_back(info);
191  }
192}
193
194base::MessageLoopProxy* MessageLoopResource::GetMessageLoopProxy() {
195  return loop_proxy_.get();
196}
197
198bool MessageLoopResource::CurrentlyHandlingBlockingMessage() {
199  return currently_handling_blocking_message_;
200}
201
202// static
203void MessageLoopResource::ReleaseMessageLoop(void* value) {
204  static_cast<MessageLoopResource*>(value)->DetachFromThread();
205}
206
207// -----------------------------------------------------------------------------
208
209PP_Resource Create(PP_Instance instance) {
210  ProxyAutoLock lock;
211  // Validate the instance.
212  PluginDispatcher* dispatcher = PluginDispatcher::GetForInstance(instance);
213  if (!dispatcher)
214    return 0;
215  return (new MessageLoopResource(instance))->GetReference();
216}
217
218PP_Resource GetForMainThread() {
219  ProxyAutoLock lock;
220  return PluginGlobals::Get()->loop_for_main_thread()->GetReference();
221}
222
223PP_Resource GetCurrent() {
224  ProxyAutoLock lock;
225  Resource* resource = MessageLoopResource::GetCurrent();
226  if (resource)
227    return resource->GetReference();
228  return 0;
229}
230
231int32_t AttachToCurrentThread(PP_Resource message_loop) {
232  EnterMessageLoop enter(message_loop, true);
233  if (enter.succeeded())
234    return enter.object()->AttachToCurrentThread();
235  return PP_ERROR_BADRESOURCE;
236}
237
238int32_t Run(PP_Resource message_loop) {
239  EnterMessageLoop enter(message_loop, true);
240  if (enter.succeeded())
241    return enter.object()->Run();
242  return PP_ERROR_BADRESOURCE;
243}
244
245int32_t PostWork(PP_Resource message_loop,
246                 PP_CompletionCallback callback,
247                 int64_t delay_ms) {
248  EnterMessageLoop enter(message_loop, true);
249  if (enter.succeeded())
250    return enter.object()->PostWork(callback, delay_ms);
251  return PP_ERROR_BADRESOURCE;
252}
253
254int32_t PostQuit(PP_Resource message_loop, PP_Bool should_destroy) {
255  EnterMessageLoop enter(message_loop, true);
256  if (enter.succeeded())
257    return enter.object()->PostQuit(should_destroy);
258  return PP_ERROR_BADRESOURCE;
259}
260
261const PPB_MessageLoop_1_0 ppb_message_loop_interface = {
262  &Create,
263  &GetForMainThread,
264  &GetCurrent,
265  &AttachToCurrentThread,
266  &Run,
267  &PostWork,
268  &PostQuit
269};
270
271PPB_MessageLoop_Proxy::PPB_MessageLoop_Proxy(Dispatcher* dispatcher)
272    : InterfaceProxy(dispatcher) {
273}
274
275PPB_MessageLoop_Proxy::~PPB_MessageLoop_Proxy() {
276}
277
278// static
279const PPB_MessageLoop_1_0* PPB_MessageLoop_Proxy::GetInterface() {
280  return &ppb_message_loop_interface;
281}
282
283}  // namespace proxy
284}  // namespace ppapi
285