Disk cache v3 ref2

net/disk_cache/v3/sparse_control_v3.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.
 
-#ifndef NET_DISK_CACHE_SPARSE_CONTROL_H_
-#define NET_DISK_CACHE_SPARSE_CONTROL_H_
+#ifndef NET_DISK_CACHE_V3_SPARSE_CONTROL_V3_H_
+#define NET_DISK_CACHE_V3_SPARSE_CONTROL_V3_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "net/base/completion_callback.h"
 #include "net/disk_cache/bitmap.h"
-#include "net/disk_cache/disk_format.h"
+#include "net/disk_cache/disk_format_base.h"
 
 namespace net {
 class IOBuffer;
 class DrainableIOBuffer;
 }
 
 namespace disk_cache {
 
 class Entry;
-class EntryImpl;
+class EntryImplV3;
 
 // This class provides support for the sparse capabilities of the disk cache.
 // Basically, sparse IO is directed from EntryImpl to this class, and we split
 // the operation into multiple small pieces, sending each one to the
 // appropriate entry. An instance of this class is asociated with each entry
 // used directly for sparse operations (the entry passed in to the constructor).
-class SparseControl {
+class SparseControlV3 {
  public:
   typedef net::CompletionCallback CompletionCallback;
 
   // The operation to perform.
   enum SparseOperation {
     kNoOperation,
     kReadOperation,
     kWriteOperation,
     kGetRangeOperation
   };
 
-  explicit SparseControl(EntryImpl* entry);
-  ~SparseControl();
+  explicit SparseControlV3(EntryImplV3* entry);
+  ~SparseControlV3();
+
+  void Close();
 
   // Performs a quick test to see if the entry is sparse or not, without
   // generating disk IO (so the answer provided is only a best effort).
   bool CouldBeSparse() const;
 
   // Performs an actual sparse read or write operation for this entry. |op| is
   // the operation to perform, |offset| is the desired sparse offset, |buf| and
   // |buf_len| specify the actual data to use and |callback| is the callback
   // to use for asynchronous operations. See the description of the Read /
   // WriteSparseData for details about the arguments. The return value is the
   // number of bytes read or written, or a net error code.
   int StartIO(SparseOperation op, int64 offset, net::IOBuffer* buf,
               int buf_len, const CompletionCallback& callback);
 
   // Implements Entry::GetAvailableRange().
-  int GetAvailableRange(int64 offset, int len, int64* start);
+  int GetAvailableRange(int64 offset, int len, int64* start,
+                        const CompletionCallback& callback);
 
   // Cancels the current sparse operation (if any).
   void CancelIO();
 
   // Returns OK if the entry can be used for new IO or ERR_IO_PENDING if we are
   // busy. If the entry is busy, we'll invoke the callback when we are ready
   // again. See disk_cache::Entry::ReadyToUse() for more info.
   int ReadyToUse(const CompletionCallback& completion_callback);
 
   // Deletes the children entries of |entry|.
-  static void DeleteChildren(EntryImpl* entry);
+  static void DeleteChildren(EntryImplV3* entry);
 
  private:
-  // Initializes the object for the current entry. If this entry already stores
-  // sparse data, or can be used to do it, it updates the relevant information
-  // on disk and returns net::OK. Otherwise it returns a net error code.
-  int Init();
+  enum State {
+    STATE_NONE,
+    STATE_INIT,
+    STATE_CREATE_SPARSE_ENTRY,
+    STATE_CREATE_SPARSE_ENTRY_COMPLETE,
+    STATE_OPEN_SPARSE_ENTRY,
+    STATE_OPEN_SPARSE_ENTRY_COMPLETE,
+    STATE_READ_BITMAP_COMPLETE,
+    STATE_GET_CHILD_KEY,
+    STATE_OPEN_CHILD,
+    STATE_OPEN_CHILD_COMPLETE,
+    STATE_READ_SIGNATURE_COMPLETE,
+    STATE_CLOSE_CHILD,
+    STATE_CLOSE_CHILD_COMPLETE,
+    STATE_CREATE_CHILD,
+    STATE_CREATE_CHILD_COMPLETE,
+    STATE_WRITE_BITMAP,
+    STATE_WRITE_BITMAP_COMPLETE,
+    STATE_DO_CHILD_IO,
+    STATE_DO_CHILD_IO_COMPLETE,
+    STATE_CLOSE    
+  };
 
-  // Creates a new sparse entry or opens an aready created entry from disk.
-  // These methods just read / write the required info from disk for the current
-  // entry, and verify that everything is correct. The return value is a net
-  // error code.
-  int CreateSparseEntry();
-  int OpenSparseEntry(int data_len);
-
-  // Opens and closes a child entry. A child entry is a regular EntryImpl object
-  // with a key derived from the key of the resource to store and the range
-  // stored by that child.
-  bool OpenChild();
-  void CloseChild();
-
-  // Continues the current operation (open) without a current child.
-  bool ContinueWithoutChild(const std::string& key);
-
-    // Writes to disk the tracking information for this entry.
-  void WriteSparseData();
-
-  // Performs a single operation with the current child. Returns true when we
-  // should move on to the next child and false when we should interrupt our
-  // work.
-  bool DoChildIO();
-
-  // Performs the required work after a single IO operations finishes.
-  void DoChildIOCompleted(int result);
+  int DoLoop(int result);
+  int DoInit();
+  int DoCreateSparseEntry();
+  int DoCreateSparseEntryComplete(int result);
+  int DoOpenSparseEntry(int data_len);
+  int DoOpenSparseEntryComplete(int result);
+  int DoReadBitmapComplete(int result);
+  int DoGetChildKey();
+  int DoOpenChild();
+  int DoOpenChildComplete(int result);
+  int DoReadSignatureComplete(int result);
+  int DoCloseChild();
+  int DoCloseChildComplete(int result);
+  int DoCreateChild();
+  int DoCreateChildComplete(int result);
+  int DoWriteBitmap();
+  int DoWriteBitmapComplete(int result);
+  int DoChildIO();
+  int DoChildIOComplete(int result);
+  int DoClose();
 
   std::string GenerateChildKey();
 
   // Deletes the current child and continues the current operation (open).
-  bool KillChildAndContinue(const std::string& key, bool fatal);
+  int KillChildAndContinue();
 
   // Returns true if the required child is tracked by the parent entry, i.e. it
   // was already created.
   bool ChildPresent();
 
   // Sets the bit for the current child to the provided |value|. In other words,
   // starts or stops tracking this child.
   void SetChildBit(bool value);
 
   // Verify that the range to be accessed for the current child is appropriate.
   // Returns false if an error is detected or there is no need to perform the
   // current IO operation (for instance if the required range is not stored by
   // the child).
   bool VerifyRange();
 
   // Updates the contents bitmap for the current range, based on the result of
   // the current operation.
   void UpdateRange(int result);
 
   // Returns the number of bytes stored at |block_index|, if its allocation-bit
   // is off (because it is not completely filled).
   int PartialBlockLength(int block_index) const;
 
   // Initializes the sparse info for the current child.
   void InitChildData();
 
   // Performs the required work for GetAvailableRange for one child.
-  int DoGetAvailableRange();
+  int GetAvailableRangeImpl();
+
+  void LogChildOperationStart();
+  void LogChildOperationEnd(int result);
+  int LogCompletion(int result);
 
   // Reports to the user that we are done.
-  void DoUserCallback();
-  void DoAbortCallbacks();
+  void HandleResult(int result);
+  void HanldeAbortCallbacks();
 
   // Invoked by the callback of asynchronous operations.
-  void OnChildIOCompleted(int result);
+  void OnIOComplete(int result);
 
-  EntryImpl* entry_;  // The sparse entry.
-  EntryImpl* child_;  // The current child entry.
+  EntryImplV3* entry_;  // The sparse entry.
+  Entry* child_;  // The current child entry.
   SparseOperation operation_;
-  bool pending_;  // True if any child IO operation returned pending.
-  bool finished_;
+  State next_state_;
   bool init_;
   bool range_found_;  // True if GetAvailableRange found something.
   bool abort_;  // True if we should abort the current operation ASAP.
+  bool valid_;
+  bool closing_;
 
   SparseHeader sparse_header_;  // Data about the children of entry_.
   Bitmap children_map_;  // The actual bitmap of children.
   SparseData child_data_;  // Parent and allocation map of child_.
   Bitmap child_map_;  // The allocation map as a bitmap.
 
   CompletionCallback user_callback_;
+  CompletionCallback callback_;
   std::vector<CompletionCallback> abort_callbacks_;
   int64 offset_;  // Current sparse offset.
   scoped_refptr<net::DrainableIOBuffer> user_buf_;
+  scoped_refptr<net::IOBuffer> buf_;
+  std::string key_;
   int buf_len_;  // Bytes to read or write.
   int child_offset_;  // Offset to use for the current child.
   int child_len_;  // Bytes to read or write for this child.
   int result_;
+  int64* range_start_;
 
-  DISALLOW_COPY_AND_ASSIGN(SparseControl);
+  DISALLOW_COPY_AND_ASSIGN(SparseControlV3);
 };
 
 }  // namespace disk_cache
 
-#endif  // NET_DISK_CACHE_SPARSE_CONTROL_H_
+#endif  // NET_DISK_CACHE_V3_SPARSE_CONTROL_V3_H_