net: Implement canceling of all async operations in FileStream.

net/base/file_stream_posix.h

 // Copyright (c) 2012 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.
 
 // This file implements FileStream for POSIX.
 
 #ifndef NET_BASE_FILE_STREAM_POSIX_H_
 #define NET_BASE_FILE_STREAM_POSIX_H_
 
-#include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
+#include <errno.h>
+
 #include "base/platform_file.h"
 #include "net/base/completion_callback.h"
+#include "net/base/file_stream.h"
+#include "net/base/file_stream_metrics.h"
 #include "net/base/file_stream_whence.h"
 #include "net/base/net_export.h"
 #include "net/base/net_log.h"
 
 class FilePath;
 
-namespace base {
-class WaitableEvent;
-}
-
 namespace net {
 
 class IOBuffer;
 
-class NET_EXPORT FileStreamPosix {
+class FileStream::Context {
  public:
-  explicit FileStreamPosix(net::NetLog* net_log);
-  FileStreamPosix(base::PlatformFile file, int flags, net::NetLog* net_log);
-  ~FileStreamPosix();
+  explicit Context(const BoundNetLog& bound_net_log);
+  Context(base::PlatformFile file,
+          const BoundNetLog& bound_net_log,
+          int open_flags);
+  ~Context();
 
-  // FileStream implementations.
-  void Close(const CompletionCallback& callback);
+  // Destroys the context. It can be deleted in the method or deletion can be
+  // deferred to WorkerPool if some asynchronous operation is now in progress
+  // or if auto-closing is needed.
+  void Orphan();
+
+  bool record_uma() const { return record_uma_; }
+  void set_record_uma(bool value) { record_uma_ = value; }
+  base::PlatformFile file() const { return file_; }
+  bool async_in_progress() const { return async_in_progress_; }
+
+  // Sync and async versions of all operations
+  void OpenAsync(const FilePath& path,
+                 int open_flags,
+                 const CompletionCallback& callback);
+  int OpenSync(const FilePath& path, int open_flags);
+
+  void CloseAsync(const CompletionCallback& callback);
   void CloseSync();
-  int Open(const FilePath& path, int open_flags,
-           const CompletionCallback& callback);
-  int OpenSync(const FilePath& path, int open_flags);
-  bool IsOpen() const;
-  int Seek(Whence whence, int64 offset,
-           const Int64CompletionCallback& callback);
+
+  void SeekAsync(Whence whence,
+                 int64 offset,
+                 const Int64CompletionCallback& callback);
   int64 SeekSync(Whence whence, int64 offset);
-  int64 Available();
-  int Read(IOBuffer* buf, int buf_len, const CompletionCallback& callback);
+
+  int64 GetFileSize() const;
+
+  int ReadAsync(IOBuffer* buf,
+                int buf_len,
+                const CompletionCallback& callback);
   int ReadSync(char* buf, int buf_len);
-  int ReadUntilComplete(char *buf, int buf_len);
-  int Write(IOBuffer* buf, int buf_len, const CompletionCallback& callback);
+
+  int WriteAsync(IOBuffer* buf,
+                 int buf_len,
+                 const CompletionCallback& callback);
   int WriteSync(const char* buf, int buf_len);
-  int64 Truncate(int64 bytes);
+
   int Flush();
-  void EnableErrorStatistics();
-  void SetBoundNetLogSource(
-      const net::BoundNetLog& owner_bound_net_log);
-  base::PlatformFile GetPlatformFileForTesting();
 
-  // Resets on_io_complete_ and WeakPtr's.
-  // Called when Read() or Write() is completed.
-  void ResetOnIOComplete();
+  int Truncate(int64 bytes);
 
  private:
-  // Called when the file_ is closed asynchronously.
-  void OnClosed(const CompletionCallback& callback);
+  enum {
+    kErrorBadFile = EBADF
+  };
 
-  // Waits until the in-flight async open/close/read/write operation is
-  // complete.
-  void WaitForIOCompletion();
+  struct OpenResult {
+    base::PlatformFile file;
+    int error_code;
+  };
+
+  // Stubs to make more of the Context code multi-platform.

[willchan no longer on Chromium, 2012/09/11 23:05:02]

Can you use banner comments to indicate which section is used by file_stream.cc
and which section is local to this specific implementation? I thought a lot
about this, and I've come around to your point of view that things are clearer
when we share more stuff in file_stream.cc, but it was a bit confusing when I
saw GetLastErrno() and was trying to figure out who called it.

+  int GetLastErrno() { return errno; }
+  void OnAsyncFileOpened() {}
+
+  // Map system error into network error code and log it with |bound_net_log_|.
+  int RecordAndMapError(int error, FileErrorSource source) const;
+
+  void BeginOpenEvent(const FilePath& path);
+
+  // Opens a file.
+  OpenResult OpenFileImpl(const FilePath& path, int open_flags);
+
+  int ProcessOpenError(int error_code);
+  void OnOpenCompleted(const CompletionCallback& callback, OpenResult result);
+
+  void OnCloseCompleted(const CompletionCallback& callback);
+
+  // Adjusts the position from where the data is read.
+  int64 SeekFileImpl(Whence whence, int64 offset);
+
+  // ReadFile() is a simple wrapper around read() that handles EINTR signals
+  // and calls RecordAndMapError() to map errno to net error codes.
+  int64 ReadFileImpl(scoped_refptr<IOBuffer> buf, int buf_len);
+
+  // WriteFile() is a simple wrapper around write() that handles EINTR signals
+  // and calls MapSystemError() to map errno to net error codes. It tries
+  // to write to completion.
+  int64 WriteFileImpl(scoped_refptr<IOBuffer> buf, int buf_len);
+
+  Int64CompletionCallback IntToInt64(const CompletionCallback& callback);
+
+  // Checks for IO error that probably happened in ReadFileImpl(),
+  // WriteFileImpl() or SeekFileImpl(). If there was error reports it.
+  void CheckForIOError(int64* result, FileErrorSource source);
+
+  // Called when asynchronous Read(), Write() or Seek() is completed.
+  // Reports error if needed and calls callback.
+  void ProcessAsyncResult(const Int64CompletionCallback& callback,
+                          FileErrorSource source,
+                          int64 result);
+
+  // Called when asynchronous Open(), Read(), Write() or Seek()
+  // is completed. |result| contains the result or a network error code.
+  void OnAsyncCompleted(const Int64CompletionCallback& callback, int64 result);
 
   base::PlatformFile file_;
-  int open_flags_;
-  bool auto_closed_;
   bool record_uma_;
-  net::BoundNetLog bound_net_log_;
-  base::WeakPtrFactory<FileStreamPosix> weak_ptr_factory_;
-  scoped_ptr<base::WaitableEvent> on_io_complete_;
+  bool async_in_progress_;
+  bool orphaned_;
+  BoundNetLog bound_net_log_;
 
-  DISALLOW_COPY_AND_ASSIGN(FileStreamPosix);
+  DISALLOW_COPY_AND_ASSIGN(Context);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_FILE_STREAM_POSIX_H