VideoCaptureHost

content/browser/renderer_host/video_capture_host.cc

+// Copyright (c) 2011 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 "content/browser/renderer_host/video_capture_host.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "base/stl_util-inl.h"
+#include "content/browser/media_stream/video_capture_manager.h"
+#include "content/common/video_capture_messages.h"
+
+VideoCaptureHost::VideoCaptureHost() {}
+
+VideoCaptureHost::~VideoCaptureHost() {
+  DCHECK(vc_entries_.empty());
+  // Delete all Memory handlers that have been stopped but not returned all
+  // TransportDIBs.
+  STLDeleteContainerPairSecondPointers(vc_stoped_entries_.begin(),
+                                       vc_stoped_entries_.end());
+  vc_stoped_entries_.clear();
+}
+
+void VideoCaptureHost::OnChannelClosing() {
+  BrowserMessageFilter::OnChannelClosing();
+
+  // Since the IPC channel is gone, close all requested VideCaptureDevices.
+  for (VCEntryMap::iterator it = vc_entries_.begin();
+       it != vc_entries_.end(); it++) {
+    StopVideoCapture(it->second->entry_id());
+  }
+}
+
+void VideoCaptureHost::OnDestruct() const {
+  BrowserThread::DeleteOnIOThread::Destruct(this);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+// Implements VideoCaptureMemory::EventHandler.
+void VideoCaptureHost::OnError(VideoCaptureMemory::VCEntryId entry) {
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(this, &VideoCaptureHost::DoHandleError, entry));
+}
+
+void VideoCaptureHost::OnBufferReady(VideoCaptureMemory::VCEntryId entry,
+                                     TransportDIB::Handle handle,
+                                     base::Time timestamp) {
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(this, &VideoCaptureHost::DoSendFilledBuffer, entry,
+                        handle, timestamp));
+}
+
+void VideoCaptureHost::OnFrameInfo(VideoCaptureMemory::VCEntryId entry,
+                                   int width,
+                                   int height,
+                                   int frame_per_second) {
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(this, &VideoCaptureHost::DoSendFrameInfo, entry, width,
+                        height, frame_per_second));
+}
+
+void VideoCaptureHost::DoSendFilledBuffer(VideoCaptureMemory::VCEntryId entry,
+                                          TransportDIB::Handle handle,
+                                          base::Time timestamp) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  Send(new VideoCaptureMsg_BufferReady(entry.render_id, entry.device_id, handle,
+                                       timestamp));
+}
+
+void VideoCaptureHost::DoHandleError(VideoCaptureMemory::VCEntryId entry) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  SendErrorMessage(entry.render_id, entry.device_id);
+  StopVideoCapture(entry);
+}
+
+void VideoCaptureHost::DoSendFrameInfo(VideoCaptureMemory::VCEntryId entry,
+                                       int width,
+                                       int height,
+                                       int frame_per_second) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  media::VideoCaptureParams params;
+  params.width = width;
+  params.height = height;
+  params.frame_per_second = frame_per_second;
+  Send(new VideoCaptureMsg_DeviceInfo(entry.render_id,
+                                      entry.device_id,
+                                      params));
+  Send(new VideoCaptureMsg_StateChanged(entry.render_id, entry.device_id,
+                                        media::VideoCapture::kStarted));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// IPC Messages handler.
+bool VideoCaptureHost::OnMessageReceived(const IPC::Message& message,
+                                         bool* message_was_ok) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_EX(VideoCaptureHost, message, *message_was_ok)
+  IPC_MESSAGE_HANDLER(VideoCaptureHostMsg_Start, OnStartCapture)
+  IPC_MESSAGE_HANDLER(VideoCaptureHostMsg_Pause, OnPauseCapture)
+  IPC_MESSAGE_HANDLER(VideoCaptureHostMsg_Stop, OnStopCapture)
+  IPC_MESSAGE_HANDLER(VideoCaptureHostMsg_BufferReady, OnReceiveEmptyBuffer)
+  IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP_EX()
+
+  return handled;
+}
+
+void VideoCaptureHost::OnStartCapture(
+                            const IPC::Message& msg, int device_id,

[wjia(left Chromium), 2011/05/11 23:23:31]

indent

[Per K, 2011/05/16 11:49:39]

Done.

+                            const media::VideoCaptureParams& params) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  VideoCaptureMemory::VCEntryId entry(msg.routing_id(),
+                                      device_id,
+                                      params.session_id);
+  // Check that it is not already started.
+  DCHECK(LookupStartedDevicesById(device_id) == NULL);
+  VideoCaptureMemory* memory_handler = new VideoCaptureMemory(this, entry);
+  if (!memory_handler) {
+    SendErrorMessage(msg.routing_id(), device_id);
+    return;
+  }
+
+  media_stream::VideoCaptureManager* manager =
+      media_stream::VideoCaptureManager::Get();
+  // Order the manager to start the actual capture.
+  manager->Start(params, memory_handler);
+
+  vc_entries_.insert(std::make_pair(device_id, memory_handler));

[wjia(left Chromium), 2011/05/11 23:23:31]

Some thoughts about the modules: 
1. Host only needs to know device_id, routing_id and memory_handler. It doesn't
need to know session_id. 
2. memory_handler doesn't need to know routing_id and device_id.
3. the communication interface between Host and Memory is
VideoCaptureMemory::EventHandler.

[Per K, 2011/05/16 11:49:39]

VCEntryId moved to VideoCaptureHost and called VideoCaptureEntry. 
VideoCaptureMemory still have a member called device_id but this is given to the
VideoCaptureMemory when it is constructed. This is used for identification so
that it can always be used in the entries_ map for quick lookup.

+}
+
+void VideoCaptureHost::OnStopCapture(const IPC::Message& msg, int device_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  VideoCaptureMemory* memory_handler = LookupStartedDevicesById(device_id);

[wjia(left Chromium), 2011/05/11 23:23:31]

would it be good to pass Stop command to memory_handler and let it handle all
buffers? when memory_handler has received all DIB's, it's stopped and call a
event handling function to notify Host.

[Per K, 2011/05/16 11:49:39]

Done.

+  if (!memory_handler) {
+    // Check if the device is being stopped
+    if (!LookupStopedDevicesById(device_id)) {
+      // It does not exist so it must have been stopped already.
+      Send(new VideoCaptureMsg_StateChanged(msg.routing_id(), device_id,
+                                            media::VideoCapture::kStopped));
+    }
+    return;
+  }
+  StopVideoCapture(memory_handler->entry_id());
+}
+
+void VideoCaptureHost::OnPauseCapture(const IPC::Message& msg, int device_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  // Not used.
+  SendErrorMessage(msg.routing_id(), device_id);
+}
+
+void VideoCaptureHost::OnReceiveEmptyBuffer(const IPC::Message& msg,
+                                            int device_id,
+                                            TransportDIB::Handle handle) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  VideoCaptureMemory* memory_handler = LookupStartedDevicesById(device_id);
+  if (!memory_handler || memory_handler->AddTransportDIB(handle) != 0) {
+    // This buffer do not belong to an active VideoCaptureMemory instance
+    // Check the Stopped Devices.
+    memory_handler = LookupStopedDevicesById(device_id);
+    if (memory_handler) {
+      memory_handler->AddTransportDIB(handle);
+      if (memory_handler->ReadyToDelete()) {
+        SendDeviceStopped(msg.routing_id(), device_id);
+        scoped_ptr<VideoCaptureMemory> item_to_delete(memory_handler);
+        vc_stoped_entries_.erase(device_id);
+      }
+    }
+  }
+}
+
+void VideoCaptureHost::StopVideoCapture(VideoCaptureMemory::VCEntryId entry) {
+  media_stream::VideoCaptureManager* manager =
+      media_stream::VideoCaptureManager::Get();
+  manager->Stop(entry.session_id,
+      NewRunnableMethod(this, &VideoCaptureHost::OnDeviceStoped,
+                        entry.device_id));
+}
+
+void VideoCaptureHost::OnDeviceStoped(int device_id) {
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(this, &VideoCaptureHost::DoDeviceStoped, device_id));
+}
+
+void VideoCaptureHost::DoDeviceStoped(int device_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  scoped_ptr<VideoCaptureMemory> memory_handler(
+      LookupStartedDevicesById(device_id));
+  if (!memory_handler.get()) {
+    return;
+  }
+
+  vc_entries_.erase(device_id);
+
+  // If we can not delete the memory_handler now because all
+  // DIBS have not been returned we add the vc_entry to the list of stopped
+  // devices and do it later and hopefully get the missing DIB back soon.
+  if (!memory_handler->ReadyToDelete()) {
+    vc_stoped_entries_.insert(
+        std::make_pair(device_id, memory_handler.release()));
+  } else {
+    // We have received all buffers and is ready to delete the memory pool.
+    const VideoCaptureMemory::VCEntryId entry_id = memory_handler->entry_id();
+    SendDeviceStopped(entry_id.render_id, entry_id.device_id);
+  }
+}
+
+void VideoCaptureHost::SendDeviceStopped(int32 render_view_id, int device_id) {
+  // Report that the device have successfully been stopped.
+  Send(new VideoCaptureMsg_StateChanged(render_view_id, device_id,
+                                        media::VideoCapture::kStopped));
+}
+
+void VideoCaptureHost::SendErrorMessage(int32 render_view_id, int32 device_id) {
+  Send(new VideoCaptureMsg_StateChanged(render_view_id, device_id,
+                                        media::VideoCapture::kError));

[wjia(left Chromium), 2011/05/11 23:23:31]

Is it needed for renderer process to distinguish different errors? If so, error
code is needed. It's a TODO in renderer process. It would be great if you can
add some error codes from device point of view.

[Per K, 2011/05/16 11:49:39]

I am not really sure we will be able to distinguish between errors. Most likely
the error will occur when you start a capture device. Either because of a
hardware problem or that the user has unplugged it after it was opened or
another application is using it. I don't plan to add any codes at the moment.
Most other errrors I would assume only happen if we have made something wrong in
the code. 

+}
+
+VideoCaptureMemory* VideoCaptureHost::LookupStartedDevicesById(int device_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  VCEntryMap::iterator it = vc_entries_.find(device_id);
+  if (it != vc_entries_.end()) {
+    return it->second;
+  }
+
+  return NULL;
+}
+
+VideoCaptureMemory* VideoCaptureHost::LookupStopedDevicesById(int device_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  VCEntryMap::iterator it = vc_stoped_entries_.find(device_id);
+  if (it != vc_stoped_entries_.end()) {
+    return it->second;
+  }
+
+  return NULL;
+}