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Unified Diff: net/disk_cache/disk_cache.h

Issue 992733002: Remove //net (except for Android test stuff) and sdch (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 5 years, 9 months ago
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Index: net/disk_cache/disk_cache.h
diff --git a/net/disk_cache/disk_cache.h b/net/disk_cache/disk_cache.h
deleted file mode 100644
index 769ab361b199695bc68827815fc3e481cf39666a..0000000000000000000000000000000000000000
--- a/net/disk_cache/disk_cache.h
+++ /dev/null
@@ -1,327 +0,0 @@
-// 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.
-
-// Defines the public interface of the disk cache. For more details see
-// http://dev.chromium.org/developers/design-documents/network-stack/disk-cache
-
-#ifndef NET_DISK_CACHE_DISK_CACHE_H_
-#define NET_DISK_CACHE_DISK_CACHE_H_
-
-#include <string>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/time/time.h"
-#include "net/base/cache_type.h"
-#include "net/base/completion_callback.h"
-#include "net/base/net_export.h"
-
-namespace base {
-class FilePath;
-class SingleThreadTaskRunner;
-}
-
-namespace net {
-class IOBuffer;
-class NetLog;
-}
-
-namespace disk_cache {
-
-class Entry;
-class Backend;
-
-// Returns an instance of a Backend of the given |type|. |path| points to a
-// folder where the cached data will be stored (if appropriate). This cache
-// instance must be the only object that will be reading or writing files to
-// that folder. The returned object should be deleted when not needed anymore.
-// If |force| is true, and there is a problem with the cache initialization, the
-// files will be deleted and a new set will be created. |max_bytes| is the
-// maximum size the cache can grow to. If zero is passed in as |max_bytes|, the
-// cache will determine the value to use. |thread| can be used to perform IO
-// operations if a dedicated thread is required; a valid value is expected for
-// any backend that performs operations on a disk. The returned pointer can be
-// NULL if a fatal error is found. The actual return value of the function is a
-// net error code. If this function returns ERR_IO_PENDING, the |callback| will
-// be invoked when a backend is available or a fatal error condition is reached.
-// The pointer to receive the |backend| must remain valid until the operation
-// completes (the callback is notified).
-NET_EXPORT int CreateCacheBackend(
- net::CacheType type,
- net::BackendType backend_type,
- const base::FilePath& path,
- int max_bytes,
- bool force,
- const scoped_refptr<base::SingleThreadTaskRunner>& thread,
- net::NetLog* net_log,
- scoped_ptr<Backend>* backend,
- const net::CompletionCallback& callback);
-
-// The root interface for a disk cache instance.
-class NET_EXPORT Backend {
- public:
- typedef net::CompletionCallback CompletionCallback;
-
- class Iterator {
- public:
- virtual ~Iterator() {}
-
- // OpenNextEntry returns |net::OK| and provides |next_entry| if there is an
- // entry to enumerate. It returns |net::ERR_FAILED| at the end of
- // enumeration. If the function returns |net::ERR_IO_PENDING|, then the
- // final result will be passed to the provided |callback|, otherwise
- // |callback| will not be called. If any entry in the cache is modified
- // during iteration, the result of this function is thereafter undefined.
- //
- // Calling OpenNextEntry after the backend which created it is destroyed
- // may fail with |net::ERR_FAILED|; however it should not crash.
- //
- // Some cache backends make stronger guarantees about mutation during
- // iteration, see top comment in simple_backend_impl.h for details.
- virtual int OpenNextEntry(Entry** next_entry,
- const CompletionCallback& callback) = 0;
- };
-
- // If the backend is destroyed when there are operations in progress (any
- // callback that has not been invoked yet), this method cancels said
- // operations so the callbacks are not invoked, possibly leaving the work
- // half way (for instance, dooming just a few entries). Note that pending IO
- // for a given Entry (as opposed to the Backend) will still generate a
- // callback from within this method.
- virtual ~Backend() {}
-
- // Returns the type of this cache.
- virtual net::CacheType GetCacheType() const = 0;
-
- // Returns the number of entries in the cache.
- virtual int32 GetEntryCount() const = 0;
-
- // Opens an existing entry. Upon success, |entry| holds a pointer to an Entry
- // object representing the specified disk cache entry. When the entry pointer
- // is no longer needed, its Close method should be called. The return value is
- // a net error code. If this method returns ERR_IO_PENDING, the |callback|
- // will be invoked when the entry is available. The pointer to receive the
- // |entry| must remain valid until the operation completes.
- virtual int OpenEntry(const std::string& key, Entry** entry,
- const CompletionCallback& callback) = 0;
-
- // Creates a new entry. Upon success, the out param holds a pointer to an
- // Entry object representing the newly created disk cache entry. When the
- // entry pointer is no longer needed, its Close method should be called. The
- // return value is a net error code. If this method returns ERR_IO_PENDING,
- // the |callback| will be invoked when the entry is available. The pointer to
- // receive the |entry| must remain valid until the operation completes.
- virtual int CreateEntry(const std::string& key, Entry** entry,
- const CompletionCallback& callback) = 0;
-
- // Marks the entry, specified by the given key, for deletion. The return value
- // is a net error code. If this method returns ERR_IO_PENDING, the |callback|
- // will be invoked after the entry is doomed.
- virtual int DoomEntry(const std::string& key,
- const CompletionCallback& callback) = 0;
-
- // Marks all entries for deletion. The return value is a net error code. If
- // this method returns ERR_IO_PENDING, the |callback| will be invoked when the
- // operation completes.
- virtual int DoomAllEntries(const CompletionCallback& callback) = 0;
-
- // Marks a range of entries for deletion. This supports unbounded deletes in
- // either direction by using null Time values for either argument. The return
- // value is a net error code. If this method returns ERR_IO_PENDING, the
- // |callback| will be invoked when the operation completes.
- // Entries with |initial_time| <= access time < |end_time| are deleted.
- virtual int DoomEntriesBetween(base::Time initial_time,
- base::Time end_time,
- const CompletionCallback& callback) = 0;
-
- // Marks all entries accessed since |initial_time| for deletion. The return
- // value is a net error code. If this method returns ERR_IO_PENDING, the
- // |callback| will be invoked when the operation completes.
- // Entries with |initial_time| <= access time are deleted.
- virtual int DoomEntriesSince(base::Time initial_time,
- const CompletionCallback& callback) = 0;
-
- // Returns an iterator which will enumerate all entries of the cache in an
- // undefined order.
- virtual scoped_ptr<Iterator> CreateIterator() = 0;
-
- // Return a list of cache statistics.
- virtual void GetStats(
- std::vector<std::pair<std::string, std::string> >* stats) = 0;
-
- // Called whenever an external cache in the system reuses the resource
- // referred to by |key|.
- virtual void OnExternalCacheHit(const std::string& key) = 0;
-};
-
-// This interface represents an entry in the disk cache.
-class NET_EXPORT Entry {
- public:
- typedef net::CompletionCallback CompletionCallback;
- typedef net::IOBuffer IOBuffer;
-
- // Marks this cache entry for deletion.
- virtual void Doom() = 0;
-
- // Releases this entry. Calling this method does not cancel pending IO
- // operations on this entry. Even after the last reference to this object has
- // been released, pending completion callbacks may be invoked.
- virtual void Close() = 0;
-
- // Returns the key associated with this cache entry.
- virtual std::string GetKey() const = 0;
-
- // Returns the time when this cache entry was last used.
- virtual base::Time GetLastUsed() const = 0;
-
- // Returns the time when this cache entry was last modified.
- virtual base::Time GetLastModified() const = 0;
-
- // Returns the size of the cache data with the given index.
- virtual int32 GetDataSize(int index) const = 0;
-
- // Copies cached data into the given buffer of length |buf_len|. Returns the
- // number of bytes read or a network error code. If this function returns
- // ERR_IO_PENDING, the completion callback will be called on the current
- // thread when the operation completes, and a reference to |buf| will be
- // retained until the callback is called. Note that as long as the function
- // does not complete immediately, the callback will always be invoked, even
- // after Close has been called; in other words, the caller may close this
- // entry without having to wait for all the callbacks, and still rely on the
- // cleanup performed from the callback code.
- virtual int ReadData(int index, int offset, IOBuffer* buf, int buf_len,
- const CompletionCallback& callback) = 0;
-
- // Copies data from the given buffer of length |buf_len| into the cache.
- // Returns the number of bytes written or a network error code. If this
- // function returns ERR_IO_PENDING, the completion callback will be called
- // on the current thread when the operation completes, and a reference to
- // |buf| will be retained until the callback is called. Note that as long as
- // the function does not complete immediately, the callback will always be
- // invoked, even after Close has been called; in other words, the caller may
- // close this entry without having to wait for all the callbacks, and still
- // rely on the cleanup performed from the callback code.
- // If truncate is true, this call will truncate the stored data at the end of
- // what we are writing here.
- virtual int WriteData(int index, int offset, IOBuffer* buf, int buf_len,
- const CompletionCallback& callback,
- bool truncate) = 0;
-
- // Sparse entries support:
- //
- // A Backend implementation can support sparse entries, so the cache keeps
- // track of which parts of the entry have been written before. The backend
- // will never return data that was not written previously, so reading from
- // such region will return 0 bytes read (or actually the number of bytes read
- // before reaching that region).
- //
- // There are only two streams for sparse entries: a regular control stream
- // (index 0) that must be accessed through the regular API (ReadData and
- // WriteData), and one sparse stream that must me accessed through the sparse-
- // aware API that follows. Calling a non-sparse aware method with an index
- // argument other than 0 is a mistake that results in implementation specific
- // behavior. Using a sparse-aware method with an entry that was not stored
- // using the same API, or with a backend that doesn't support sparse entries
- // will return ERR_CACHE_OPERATION_NOT_SUPPORTED.
- //
- // The storage granularity of the implementation should be at least 1 KB. In
- // other words, storing less than 1 KB may result in an implementation
- // dropping the data completely, and writing at offsets not aligned with 1 KB,
- // or with lengths not a multiple of 1 KB may result in the first or last part
- // of the data being discarded. However, two consecutive writes should not
- // result in a hole in between the two parts as long as they are sequential
- // (the second one starts where the first one ended), and there is no other
- // write between them.
- //
- // The Backend implementation is free to evict any range from the cache at any
- // moment, so in practice, the previously stated granularity of 1 KB is not
- // as bad as it sounds.
- //
- // The sparse methods don't support multiple simultaneous IO operations to the
- // same physical entry, so in practice a single object should be instantiated
- // for a given key at any given time. Once an operation has been issued, the
- // caller should wait until it completes before starting another one. This
- // requirement includes the case when an entry is closed while some operation
- // is in progress and another object is instantiated; any IO operation will
- // fail while the previous operation is still in-flight. In order to deal with
- // this requirement, the caller could either wait until the operation
- // completes before closing the entry, or call CancelSparseIO() before closing
- // the entry, and call ReadyForSparseIO() on the new entry and wait for the
- // callback before issuing new operations.
-
- // Behaves like ReadData() except that this method is used to access sparse
- // entries.
- virtual int ReadSparseData(int64 offset, IOBuffer* buf, int buf_len,
- const CompletionCallback& callback) = 0;
-
- // Behaves like WriteData() except that this method is used to access sparse
- // entries. |truncate| is not part of this interface because a sparse entry
- // is not expected to be reused with new data. To delete the old data and
- // start again, or to reduce the total size of the stream data (which implies
- // that the content has changed), the whole entry should be doomed and
- // re-created.
- virtual int WriteSparseData(int64 offset, IOBuffer* buf, int buf_len,
- const CompletionCallback& callback) = 0;
-
- // Returns information about the currently stored portion of a sparse entry.
- // |offset| and |len| describe a particular range that should be scanned to
- // find out if it is stored or not. |start| will contain the offset of the
- // first byte that is stored within this range, and the return value is the
- // minimum number of consecutive stored bytes. Note that it is possible that
- // this entry has stored more than the returned value. This method returns a
- // net error code whenever the request cannot be completed successfully. If
- // this method returns ERR_IO_PENDING, the |callback| will be invoked when the
- // operation completes, and |start| must remain valid until that point.
- virtual int GetAvailableRange(int64 offset, int len, int64* start,
- const CompletionCallback& callback) = 0;
-
- // Returns true if this entry could be a sparse entry or false otherwise. This
- // is a quick test that may return true even if the entry is not really
- // sparse. This method doesn't modify the state of this entry (it will not
- // create sparse tracking data). GetAvailableRange or ReadSparseData can be
- // used to perform a definitive test of whether an existing entry is sparse or
- // not, but that method may modify the current state of the entry (making it
- // sparse, for instance). The purpose of this method is to test an existing
- // entry, but without generating actual IO to perform a thorough check.
- virtual bool CouldBeSparse() const = 0;
-
- // Cancels any pending sparse IO operation (if any). The completion callback
- // of the operation in question will still be called when the operation
- // finishes, but the operation will finish sooner when this method is used.
- virtual void CancelSparseIO() = 0;
-
- // Returns OK if this entry can be used immediately. If that is not the
- // case, returns ERR_IO_PENDING and invokes the provided callback when this
- // entry is ready to use. This method always returns OK for non-sparse
- // entries, and returns ERR_IO_PENDING when a previous operation was cancelled
- // (by calling CancelSparseIO), but the cache is still busy with it. If there
- // is a pending operation that has not been cancelled, this method will return
- // OK although another IO operation cannot be issued at this time; in this
- // case the caller should just wait for the regular callback to be invoked
- // instead of using this method to provide another callback.
- //
- // Note that CancelSparseIO may have been called on another instance of this
- // object that refers to the same physical disk entry.
- // Note: This method is deprecated.
- virtual int ReadyForSparseIO(const CompletionCallback& callback) = 0;
-
- protected:
- virtual ~Entry() {}
-};
-
-struct EntryDeleter {
- void operator()(Entry* entry) {
- // Note that |entry| is ref-counted.
- entry->Close();
- }
-};
-
-// Automatically closes an entry when it goes out of scope.
-typedef scoped_ptr<Entry, EntryDeleter> ScopedEntryPtr;
-
-} // namespace disk_cache
-
-#endif // NET_DISK_CACHE_DISK_CACHE_H_
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