Convert utility process ParseMediaMetadata blob reading IPC to mojo

chrome/utility/media_galleries/ipc_data_source.cc

Index: chrome/utility/media_galleries/ipc_data_source.cc
diff --git a/chrome/utility/media_galleries/ipc_data_source.cc b/chrome/utility/media_galleries/ipc_data_source.cc
index 63e09c449ee7dca35e4bd223ac09f4a54b3de14f..2801d217ab73ce27ddecbbf476fa3db1884e9f85 100644
--- a/chrome/utility/media_galleries/ipc_data_source.cc
+++ b/chrome/utility/media_galleries/ipc_data_source.cc
@@ -5,13 +5,15 @@
 #include "chrome/utility/media_galleries/ipc_data_source.h"
 
 #include "base/threading/thread_task_runner_handle.h"
-#include "chrome/common/extensions/chrome_utility_extensions_messages.h"
 #include "content/public/utility/utility_thread.h"
 
 namespace metadata {
 
-IPCDataSource::IPCDataSource(int64_t total_size)
-    : total_size_(total_size),
+IPCDataSource::IPCDataSource(
+    extensions::mojom::MediaDataSourcePtr media_data_source,
+    int64_t total_size)
+    : media_data_source_(std::move(media_data_source)),

[Sam McNally, 2017/02/03 22:14:16]

It's probably worth crashing if |media_data_source_| has an error.

[Noel Gordon, 2017/02/05 23:45:03]

Ok, added a Crash() helper which calls IMMEDIATE_CRASH() from base/logging.h

+      total_size_(total_size),
       utility_task_runner_(base::ThreadTaskRunnerHandle::Get()),
       next_request_id_(0) {
   data_source_thread_checker_.DetachFromThread();
@@ -34,10 +36,10 @@ void IPCDataSource::Read(int64_t position,
                          uint8_t* data,
                          const DataSource::ReadCB& read_cb) {
   DCHECK(data_source_thread_checker_.CalledOnValidThread());
+
   utility_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&IPCDataSource::ReadOnUtilityThread, base::Unretained(this),
-                 position, size, data, read_cb));
+      FROM_HERE, base::Bind(&IPCDataSource::ReadBlob, base::Unretained(this),
+                            position, size, data, read_cb));
 }
 
 bool IPCDataSource::GetSize(int64_t* size_out) {
@@ -55,30 +57,18 @@ void IPCDataSource::SetBitrate(int bitrate) {
   DCHECK(data_source_thread_checker_.CalledOnValidThread());
 }
 
-bool IPCDataSource::OnMessageReceived(const IPC::Message& message) {
-  DCHECK(utility_thread_checker_.CalledOnValidThread());
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(IPCDataSource, message)
-    IPC_MESSAGE_HANDLER(ChromeUtilityMsg_RequestBlobBytes_Finished,
-                        OnRequestBlobBytesFinished)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
-}
-
-IPCDataSource::Request::Request()
-    : destination(NULL) {
-}
-
-IPCDataSource::Request::Request(const Request& other) = default;
-
-IPCDataSource::Request::~Request() {
-}
-
-void IPCDataSource::ReadOnUtilityThread(int64_t position,
-                                        int size,
-                                        uint8_t* data,
-                                        const DataSource::ReadCB& read_cb) {
+struct IPCDataSource::Request {

[Sam McNally, 2017/02/03 22:14:16]

Bind |destination| and |callback| into the mojo callback instead of storing in a
map.

[Noel Gordon, 2017/02/05 23:45:03]

Removed the map, and curried destination and the read callback into the mojo
callback.

+  Request() : destination(nullptr) {}
+  Request(const Request& other) = default;
+  ~Request() = default;
+  uint8_t* destination;
+  ReadCB callback;
+};
+
+void IPCDataSource::ReadBlob(int64_t position,
+                             int size,
+                             uint8_t* data,
+                             const DataSource::ReadCB& read_cb) {
   DCHECK(utility_thread_checker_.CalledOnValidThread());
   CHECK_GE(total_size_, 0);
   CHECK_GE(position, 0);
@@ -96,22 +86,24 @@ void IPCDataSource::ReadOnUtilityThread(int64_t position,
   request.callback = read_cb;
 
   pending_requests_[request_id] = request;
-  content::UtilityThread::Get()->Send(new ChromeUtilityHostMsg_RequestBlobBytes(
-      request_id, position, clamped_size));
+
+  media_data_source_->ReadBlob(
+      request_id, position, clamped_size,
+      base::Bind(&IPCDataSource::ReadDone, base::Unretained(this)));
 }
 
-void IPCDataSource::OnRequestBlobBytesFinished(int64_t request_id,
-                                               const std::string& bytes) {
+void IPCDataSource::ReadDone(int64_t request_id,
+                             const std::vector<uint8_t>& data) {
   DCHECK(utility_thread_checker_.CalledOnValidThread());
-  std::map<int64_t, Request>::iterator it = pending_requests_.find(request_id);
 
-  if (it == pending_requests_.end())
+  auto request = pending_requests_.find(request_id);
+  if (request == pending_requests_.end())
     return;
 
-  std::copy(bytes.begin(), bytes.end(), it->second.destination);
-  it->second.callback.Run(bytes.size());
+  std::copy(data.begin(), data.end(), request->second.destination);
+  request->second.callback.Run(data.size());
 
-  pending_requests_.erase(it);
+  pending_requests_.erase(request);
 }
 
 }  // namespace metadata