arc: Implement ArcContentFileSystemFileStreamReader::Read/GetLength

chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_reader.cc

Index: chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_reader.cc
diff --git a/chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_reader.cc b/chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_reader.cc
index fb41b95fc6a555a26e1935b6d99fb15ae7c39aca..3788e6e78450dde15d7d033cae301a616bd4fc8b 100644
--- a/chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_reader.cc
+++ b/chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_reader.cc
@@ -4,14 +4,28 @@
 
 #include "chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_reader.h"
 
+#include "chrome/browser/chromeos/arc/fileapi/intent_helper_util.h"
+#include "content/public/browser/browser_thread.h"
+#include "mojo/edk/embedder/embedder.h"
+#include "net/base/file_stream.h"
+#include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 
 namespace arc {
 
+namespace {
+
+void OnGetFileSize(const net::Int64CompletionCallback& callback, int64_t size) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  callback.Run(size < 0 ? net::ERR_FAILED : size);
+}
+
+}  // namespace
+
 ArcContentFileSystemFileStreamReader::ArcContentFileSystemFileStreamReader(
-    const storage::FileSystemURL& url,
-    int64_t offset,
-    int64_t max_bytes_to_read) {}
+    const GURL& arc_url,
+    int64_t offset)
+    : arc_url_(arc_url), offset_(offset), weak_ptr_factory_(this) {}
 
 ArcContentFileSystemFileStreamReader::~ArcContentFileSystemFileStreamReader() =
     default;
@@ -20,14 +34,58 @@ int ArcContentFileSystemFileStreamReader::Read(
     net::IOBuffer* buffer,
     int buffer_length,
     const net::CompletionCallback& callback) {
-  NOTIMPLEMENTED();
-  return net::ERR_NOT_IMPLEMENTED;
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  if (file_stream_)
+    return file_stream_->Read(buffer, buffer_length, callback);
+
+  if (offset_ != 0) {
+    // TODO(hashimoto): Handle offset_ != 0 cases.
+    NOTIMPLEMENTED() << "Non-zero offset is not supported yet: offset_ = "
+                     << offset_;
+    return net::ERR_FAILED;
+  }
+  intent_helper_util::OpenFileToReadOnIOThread(
+      arc_url_,
+      base::Bind(&ArcContentFileSystemFileStreamReader::OnOpenFile,
+                 weak_ptr_factory_.GetWeakPtr(), make_scoped_refptr(buffer),
+                 buffer_length, callback));
+  return net::ERR_IO_PENDING;
 }
 
 int64_t ArcContentFileSystemFileStreamReader::GetLength(
     const net::Int64CompletionCallback& callback) {
-  NOTIMPLEMENTED();
-  return net::ERR_NOT_IMPLEMENTED;
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  intent_helper_util::GetFileSizeOnIOThread(
+      arc_url_, base::Bind(&OnGetFileSize, callback));
+  return net::ERR_IO_PENDING;
+}
+
+void ArcContentFileSystemFileStreamReader::OnOpenFile(
+    scoped_refptr<net::IOBuffer> buf,
+    int buffer_length,
+    const net::CompletionCallback& callback,
+    mojo::ScopedHandle handle) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+
+  mojo::edk::ScopedPlatformHandle platform_handle;
+  if (mojo::edk::PassWrappedPlatformHandle(
+          handle.release().value(), &platform_handle) != MOJO_RESULT_OK) {
+    LOG(ERROR) << "PassWrappedPlatformHandle failed";
+    callback.Run(net::ERR_FAILED);
+    return;
+  }
+  base::File file(platform_handle.release().handle);
+  if (!file.IsValid()) {
+    LOG(ERROR) << "Invalid file.";
+    callback.Run(net::ERR_FAILED);
+    return;
+  }
+  file_stream_.reset(new net::FileStream(
+      std::move(file), content::BrowserThread::GetBlockingPool()));
+  // Resume Read().
+  int result = Read(buf.get(), buffer_length, callback);
+  if (result != net::ERR_IO_PENDING)
+    callback.Run(result);
 }
 
 }  // namespace arc