content/renderer/pepper/pepper_device_enumeration_host_helper.cc

   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/renderer/pepper/pepper_device_enumeration_host_helper.h"
   6
   7 #include "base/bind.h"
   8 #include "base/logging.h"
   9 #include "base/memory/weak_ptr.h"
  10 #include "base/message_loop/message_loop.h"
  11 #include "ipc/ipc_message.h"
  12 #include "ppapi/c/pp_errors.h"
  13 #include "ppapi/host/dispatch_host_message.h"
  14 #include "ppapi/host/host_message_context.h"
  15 #include "ppapi/host/ppapi_host.h"
  16 #include "ppapi/host/resource_host.h"
  17 #include "ppapi/proxy/ppapi_messages.h"
  18 #include "ppapi/shared_impl/ppb_device_ref_shared.h"
  19
  20 using ppapi::host::HostMessageContext;
  21
  22 namespace content {
  23
  24 // Makes sure that StopEnumerateDevices() is called for each EnumerateDevices().
  25 class PepperDeviceEnumerationHostHelper::ScopedRequest
  26     : public base::SupportsWeakPtr<ScopedRequest> {
  27  public:
  28   // |owner| must outlive this object.
  29   ScopedRequest(PepperDeviceEnumerationHostHelper* owner,
  30                 const Delegate::EnumerateDevicesCallback& callback)
  31       : owner_(owner),
  32         callback_(callback),
  33         requested_(false),
  34         request_id_(0),
  35         sync_call_(false) {
  36     if (!owner_->document_url_.is_valid())
  37       return;
  38
  39     requested_ = true;
  40
  41     // Note that the callback passed into
  42     // PepperDeviceEnumerationHostHelper::Delegate::EnumerateDevices() may be
  43     // called synchronously. In that case, |request_id_| hasn't been updated
  44     // when the callback is called. Moreover, |callback| may destroy this
  45     // object. So we don't pass in |callback| directly. Instead, we use
  46     // EnumerateDevicesCallbackBody() to ensure that we always call |callback|
  47     // asynchronously.
  48     sync_call_ = true;
  49     request_id_ = owner_->delegate_->EnumerateDevices(
  50         owner_->device_type_,
  51         owner_->document_url_,
  52         base::Bind(&ScopedRequest::EnumerateDevicesCallbackBody, AsWeakPtr()));
  53     sync_call_ = false;
  54   }
  55
  56   ~ScopedRequest() {
  57     if (requested_) {
  58       owner_->delegate_->StopEnumerateDevices(request_id_);
  59     }
  60   }
  61
  62   bool requested() const { return requested_; }
  63
  64  private:
  65   void EnumerateDevicesCallbackBody(
  66       int request_id,
  67       const std::vector<ppapi::DeviceRefData>& devices) {
  68     if (sync_call_) {
  69       base::MessageLoop::current()->PostTask(
  70           FROM_HERE,
  71           base::Bind(&ScopedRequest::EnumerateDevicesCallbackBody,
  72                      AsWeakPtr(),
  73                      request_id,
  74                      devices));
  75     } else {
  76       DCHECK_EQ(request_id_, request_id);
  77       callback_.Run(request_id, devices);
  78       // This object may have been destroyed at this point.
  79     }
  80   }
  81
  82   PepperDeviceEnumerationHostHelper* owner_;
  83   PepperDeviceEnumerationHostHelper::Delegate::EnumerateDevicesCallback
  84       callback_;
  85   bool requested_;
  86   int request_id_;
  87   bool sync_call_;
  88
  89   DISALLOW_COPY_AND_ASSIGN(ScopedRequest);
  90 };
  91
  92 PepperDeviceEnumerationHostHelper::PepperDeviceEnumerationHostHelper(
  93     ppapi::host::ResourceHost* resource_host,
  94     Delegate* delegate,
  95     PP_DeviceType_Dev device_type,
  96     const GURL& document_url)
  97     : resource_host_(resource_host),
  98       delegate_(delegate),
  99       device_type_(device_type),
 100       document_url_(document_url) {}
 101
 102 PepperDeviceEnumerationHostHelper::~PepperDeviceEnumerationHostHelper() {}
 103
 104 bool PepperDeviceEnumerationHostHelper::HandleResourceMessage(
 105     const IPC::Message& msg,
 106     HostMessageContext* context,
 107     int32_t* result) {
 108   bool return_value = false;
 109   *result = InternalHandleResourceMessage(msg, context, &return_value);
 110   return return_value;
 111 }
 112
 113 int32_t PepperDeviceEnumerationHostHelper::InternalHandleResourceMessage(
 114     const IPC::Message& msg,
 115     HostMessageContext* context,
 116     bool* handled) {
 117   *handled = true;
 118   PPAPI_BEGIN_MESSAGE_MAP(PepperDeviceEnumerationHostHelper, msg)
 119     PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(
 120         PpapiHostMsg_DeviceEnumeration_EnumerateDevices, OnEnumerateDevices)
 121     PPAPI_DISPATCH_HOST_RESOURCE_CALL(
 122         PpapiHostMsg_DeviceEnumeration_MonitorDeviceChange,
 123         OnMonitorDeviceChange)
 124     PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(
 125         PpapiHostMsg_DeviceEnumeration_StopMonitoringDeviceChange,
 126         OnStopMonitoringDeviceChange)
 127   PPAPI_END_MESSAGE_MAP()
 128
 129   *handled = false;
 130   return PP_ERROR_FAILED;
 131 }
 132
 133 int32_t PepperDeviceEnumerationHostHelper::OnEnumerateDevices(
 134     HostMessageContext* context) {
 135   if (enumerate_devices_context_.is_valid())
 136     return PP_ERROR_INPROGRESS;
 137
 138   enumerate_.reset(new ScopedRequest(
 139       this,
 140       base::Bind(&PepperDeviceEnumerationHostHelper::OnEnumerateDevicesComplete,
 141                  base::Unretained(this))));
 142   if (!enumerate_->requested())
 143     return PP_ERROR_FAILED;
 144
 145   enumerate_devices_context_ = context->MakeReplyMessageContext();
 146   return PP_OK_COMPLETIONPENDING;
 147 }
 148
 149 int32_t PepperDeviceEnumerationHostHelper::OnMonitorDeviceChange(
 150     HostMessageContext* /* context */,
 151     uint32_t callback_id) {
 152   monitor_.reset(new ScopedRequest(
 153       this,
 154       base::Bind(&PepperDeviceEnumerationHostHelper::OnNotifyDeviceChange,
 155                  base::Unretained(this),
 156                  callback_id)));
 157
 158   return monitor_->requested() ? PP_OK : PP_ERROR_FAILED;
 159 }
 160
 161 int32_t PepperDeviceEnumerationHostHelper::OnStopMonitoringDeviceChange(
 162     HostMessageContext* /* context */) {
 163   monitor_.reset(NULL);
 164   return PP_OK;
 165 }
 166
 167 void PepperDeviceEnumerationHostHelper::OnEnumerateDevicesComplete(
 168     int /* request_id */,
 169     const std::vector<ppapi::DeviceRefData>& devices) {
 170   DCHECK(enumerate_devices_context_.is_valid());
 171
 172   enumerate_.reset(NULL);
 173
 174   enumerate_devices_context_.params.set_result(PP_OK);
 175   resource_host_->host()->SendReply(
 176       enumerate_devices_context_,
 177       PpapiPluginMsg_DeviceEnumeration_EnumerateDevicesReply(devices));
 178   enumerate_devices_context_ = ppapi::host::ReplyMessageContext();
 179 }
 180
 181 void PepperDeviceEnumerationHostHelper::OnNotifyDeviceChange(
 182     uint32_t callback_id,
 183     int /* request_id */,
 184     const std::vector<ppapi::DeviceRefData>& devices) {
 185   resource_host_->host()->SendUnsolicitedReply(
 186       resource_host_->pp_resource(),
 187       PpapiPluginMsg_DeviceEnumeration_NotifyDeviceChange(callback_id,
 188                                                           devices));
 189 }
 190
 191 }  // namespace content