Convert PDF to PWG Raster using utility process.

chrome/browser/local_discovery/pwg_raster_converter.cc

Index: chrome/browser/local_discovery/pwg_raster_converter.cc
diff --git a/chrome/browser/local_discovery/pwg_raster_converter.cc b/chrome/browser/local_discovery/pwg_raster_converter.cc
index cd50d95f03faebf7797602321002e96b39bcff8b..215cbee91ae575b5f2a032829c9ba825cc92470e 100644
--- a/chrome/browser/local_discovery/pwg_raster_converter.cc
+++ b/chrome/browser/local_discovery/pwg_raster_converter.cc
@@ -4,12 +4,245 @@
 
 #include "chrome/browser/local_discovery/pwg_raster_converter.h"
 
+#include "base/cancelable_callback.h"
+#include "base/file_util.h"
+#include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
+#include "chrome/common/chrome_utility_messages.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/child_process_data.h"
+#include "content/public/browser/utility_process_host.h"
+#include "content/public/browser/utility_process_host_client.h"
 
 namespace local_discovery {
 
 namespace {
 
+using content::BrowserThread;
+
+class FileHandlers {
+ public:
+  FileHandlers() : pdf_file_(base::kInvalidPlatformFileValue),
+                   pwg_file_(base::kInvalidPlatformFileValue) { }
+
+  ~FileHandlers() {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+    if (pdf_file_ != base::kInvalidPlatformFileValue)
+      base::ClosePlatformFile(pdf_file_);
+    if (pwg_file_ != base::kInvalidPlatformFileValue)
+      base::ClosePlatformFile(pwg_file_);
+  }
+
+  void Init(base::RefCountedMemory* data);
+  bool IsValid();
+
+  base::FilePath GetPwgPath() const {
+    return temp_dir_.path().AppendASCII("output.pwg");
+  }
+
+  base::FilePath GetPdfPath() const {
+    return temp_dir_.path().AppendASCII("input.pdf");
+  }
+
+  IPC::PlatformFileForTransit GetPdfForProcess(base::ProcessHandle process) {
+    DCHECK_NE(pdf_file_, base::kInvalidPlatformFileValue);
+    IPC::PlatformFileForTransit transit =
+        IPC::GetFileHandleForProcess(pdf_file_, process, true);
+    pdf_file_ = base::kInvalidPlatformFileValue;
+    return transit;
+  }
+
+  IPC::PlatformFileForTransit GetPwgForProcess(base::ProcessHandle process) {
+    DCHECK_NE(pwg_file_, base::kInvalidPlatformFileValue);
+    IPC::PlatformFileForTransit transit =
+        IPC::GetFileHandleForProcess(pwg_file_, process, true);
+    pwg_file_ = base::kInvalidPlatformFileValue;
+    return transit;
+  }
+
+ private:
+  base::ScopedTempDir temp_dir_;
+  base::PlatformFile pdf_file_;
+  base::PlatformFile pwg_file_;
+};
+
+void FileHandlers::Init(base::RefCountedMemory* data) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+
+  if (!temp_dir_.CreateUniqueTempDir()) {
+    return;
+  }
+
+  if (static_cast<int>(data->size()) !=
+      file_util::WriteFile(GetPdfPath(),
+                           reinterpret_cast<const char*>(data->front()),
+                           data->size())) {
+    return;
+  }
+
+  // Reopen in read only mode.
+  pdf_file_ = base::CreatePlatformFile(GetPdfPath(), base::PLATFORM_FILE_OPEN |
+                                                     base::PLATFORM_FILE_READ,
+                                       NULL, NULL);
+  pwg_file_ = base::CreatePlatformFile(GetPwgPath(),
+                                       base::PLATFORM_FILE_CREATE_ALWAYS |
+                                       base::PLATFORM_FILE_APPEND, NULL, NULL);
+}
+
+bool FileHandlers::IsValid() {
+  return pdf_file_ != base::kInvalidPlatformFileValue &&
+         pwg_file_ != base::kInvalidPlatformFileValue;
+}
+
+// Converts PDF into PWG raster.
+// Class uses 3 threads: UI, IO and FILE.
+// Internal workflow is following:
+// 1. Create instance on the UI thread. (files_, settings_,)
+// 2. Create file on the FILE thread.
+// 3. Start utility process and start conversion on the IO thread.
+// 4. Run result callback on the UI thread.
+// 5. Instance is destroyed from any thread that has the last reference.
+// 6. FileHandlers destroyed on the FILE thread.
+//    This step posts |FileHandlers| to be destroyed on the FILE thread.
+// All these steps work sequentially, so no data should be accessed
+// simultaneously by several threads.
+class PwgUtilityProcessHostClient : public content::UtilityProcessHostClient {
+ public:
+  explicit PwgUtilityProcessHostClient(
+      const printing::PdfRenderSettings& settings);
+  virtual ~PwgUtilityProcessHostClient();
+
+  void Convert(base::RefCountedMemory* data,
+               const PWGRasterConverter::ResultCallback& callback);
+
+  // UtilityProcessHostClient implementation.
+  virtual void OnProcessCrashed(int exit_code);
+  virtual bool OnMessageReceived(const IPC::Message& message);
+
+ private:
+  // Message handlers.
+  void OnProcessStarted();
+  void OnSucceeded();
+  void OnFailed();
+
+  void RunCallback(bool success);
+
+  void StartProcessOnIOThread();
+
+  void RunCallbackOnUIThread(bool success);
+  void OnFilesReadyOnUIThread();
+
+  scoped_ptr<FileHandlers> files_;
+  printing::PdfRenderSettings settings_;
+  PWGRasterConverter::ResultCallback callback_;
+  base::WeakPtr<content::UtilityProcessHost> utility_process_host_;
+
+  DISALLOW_COPY_AND_ASSIGN(PwgUtilityProcessHostClient);
+};
+
+PwgUtilityProcessHostClient::PwgUtilityProcessHostClient(
+    const printing::PdfRenderSettings& settings) : settings_(settings) {
+}
+
+PwgUtilityProcessHostClient::~PwgUtilityProcessHostClient() {
+  // Delete temp directory.
+  BrowserThread::DeleteSoon(BrowserThread::FILE, FROM_HERE, files_.release());
+}
+
+void PwgUtilityProcessHostClient::Convert(
+    base::RefCountedMemory* data,
+    const PWGRasterConverter::ResultCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  callback_ = callback;
+  CHECK(!files_);
+  files_.reset(new FileHandlers());
+  BrowserThread::PostTaskAndReply(
+      BrowserThread::FILE, FROM_HERE,
+      base::Bind(&FileHandlers::Init, base::Unretained(files_.get()), data),
+      base::Bind(&PwgUtilityProcessHostClient::OnFilesReadyOnUIThread, this));
+}
+
+void PwgUtilityProcessHostClient::OnProcessCrashed(int exit_code) {
+  OnFailed();
+}
+
+bool PwgUtilityProcessHostClient::OnMessageReceived(
+  const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(PwgUtilityProcessHostClient, message)
+    IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_ProcessStarted, OnProcessStarted)
+    IPC_MESSAGE_HANDLER(
+        ChromeUtilityHostMsg_RenderPDFPagesToPWGRaster_Succeeded, OnSucceeded)
+    IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_RenderPDFPagesToPWGRaster_Failed,
+                        OnFailed)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void PwgUtilityProcessHostClient::OnProcessStarted() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (!utility_process_host_) {
+    RunCallbackOnUIThread(false);
+    return;
+  }
+
+  base::ProcessHandle process = utility_process_host_->GetData().handle;
+  utility_process_host_->Send(
+      new ChromeUtilityMsg_RenderPDFPagesToPWGRaster(
+          files_->GetPdfForProcess(process),
+          settings_,
+          files_->GetPwgForProcess(process)));
+  utility_process_host_.reset();

[Lei Zhang, 2013/11/22 01:57:24]

Actually, is this suppose to be there?

[Vitaly Buka (NO REVIEWS), 2013/11/22 08:10:05]

I guess it's safer. it's weak ptr, so it does not control lifetime but after
this point this client should not touch host.

+}
+
+void PwgUtilityProcessHostClient::OnSucceeded() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  RunCallback(true);
+}
+
+void PwgUtilityProcessHostClient::OnFailed() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  RunCallback(false);
+}
+
+void PwgUtilityProcessHostClient::OnFilesReadyOnUIThread() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (!files_->IsValid()) {
+    RunCallbackOnUIThread(false);
+    return;
+  }
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&PwgUtilityProcessHostClient::StartProcessOnIOThread, this));
+}
+
+void PwgUtilityProcessHostClient::StartProcessOnIOThread() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  utility_process_host_ =
+      content::UtilityProcessHost::Create(
+          this,
+          base::MessageLoop::current()->message_loop_proxy())->AsWeakPtr();
+  utility_process_host_->Send(new ChromeUtilityMsg_StartupPing);
+}
+
+void PwgUtilityProcessHostClient::RunCallback(bool success) {
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&PwgUtilityProcessHostClient::RunCallbackOnUIThread, this,
+                 success));
+}
+
+void PwgUtilityProcessHostClient::RunCallbackOnUIThread(bool success) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (!callback_.is_null()) {
+    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+                            base::Bind(callback_, success,
+                                       files_->GetPwgPath()));
+    callback_.Reset();
+  }
+}
+
 class PWGRasterConverterImpl : public PWGRasterConverter {
  public:
   PWGRasterConverterImpl();
@@ -20,6 +253,9 @@ class PWGRasterConverterImpl : public PWGRasterConverter {
                      const printing::PdfRenderSettings& conversion_settings,
                      const ResultCallback& callback) OVERRIDE;
  private:
+  scoped_refptr<PwgUtilityProcessHostClient> utility_client_;
+  base::CancelableCallback<ResultCallback::RunType> callback_;
+
   DISALLOW_COPY_AND_ASSIGN(PWGRasterConverterImpl);
 };
 
@@ -33,7 +269,11 @@ void PWGRasterConverterImpl::Start(
     base::RefCountedMemory* data,
     const printing::PdfRenderSettings& conversion_settings,
     const ResultCallback& callback) {
-  NOTIMPLEMENTED();
+  // Rebind cancelable callback to avoid calling callback if
+  // PWGRasterConverterImpl is destroyed.
+  callback_.Reset(callback);
+  utility_client_ = new PwgUtilityProcessHostClient(conversion_settings);
+  utility_client_->Convert(data, callback_.callback());
 }
 
 }  // namespace