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- // Copyright (c) 2011 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_HTTP_PARTIAL_DATA_H_
- #define NET_HTTP_PARTIAL_DATA_H_
- #include <stdint.h>
- #include "base/memory/weak_ptr.h"
- #include "net/base/completion_once_callback.h"
- #include "net/disk_cache/disk_cache.h"
- #include "net/http/http_byte_range.h"
- #include "net/http/http_request_headers.h"
- namespace net {
- class HttpResponseHeaders;
- class IOBuffer;
- // This class provides support for dealing with range requests and the
- // subsequent partial-content responses. We use sparse cache entries to store
- // these requests. This class is tightly integrated with HttpCache::Transaction
- // and it is intended to allow a cleaner implementation of that class.
- //
- // In order to fulfill range requests, we may have to perform a sequence of
- // reads from the cache, interleaved with reads from the network / writes to the
- // cache. This class basically keeps track of the data required to perform each
- // of those individual network / cache requests.
- class PartialData {
- public:
- PartialData();
- PartialData(const PartialData&) = delete;
- PartialData& operator=(const PartialData&) = delete;
- ~PartialData();
- // Performs initialization of the object by examining the request |headers|
- // and verifying that we can process the requested range. Returns true if
- // we can process the requested range, and false otherwise.
- bool Init(const HttpRequestHeaders& headers);
- // Sets the headers that we should use to make byte range requests. This is a
- // subset of the request extra headers, with byte-range related headers
- // removed.
- void SetHeaders(const HttpRequestHeaders& headers);
- // Restores the byte-range headers, by appending the byte range to the headers
- // provided to SetHeaders().
- void RestoreHeaders(HttpRequestHeaders* headers) const;
- // Starts the checks to perform a cache validation. Returns 0 when there is no
- // need to perform more operations because we reached the end of the request
- // (so 0 bytes should be actually returned to the user), a positive number to
- // indicate that PrepareCacheValidation should be called, or an appropriate
- // error code. If this method returns ERR_IO_PENDING, the |callback| will be
- // notified when the result is ready.
- int ShouldValidateCache(disk_cache::Entry* entry,
- CompletionOnceCallback callback);
- // Builds the required |headers| to perform the proper cache validation for
- // the next range to be fetched.
- void PrepareCacheValidation(disk_cache::Entry* entry,
- HttpRequestHeaders* headers);
- // Returns true if the current range is stored in the cache.
- bool IsCurrentRangeCached() const;
- // Returns true if the current range is the last one needed to fulfill the
- // user's request.
- bool IsLastRange() const;
- // Extracts info from headers already stored in the cache. Returns false if
- // there is any problem with the headers. |truncated| should be true if we
- // have an incomplete 200 entry due to a transfer having been interrupted.
- // |writing_in_progress| should be set to true if a transfer for this entry's
- // payload is still in progress.
- bool UpdateFromStoredHeaders(const HttpResponseHeaders* headers,
- disk_cache::Entry* entry,
- bool truncated,
- bool writing_in_progress);
- // Sets the byte current range to start again at zero (for a truncated entry).
- void SetRangeToStartDownload();
- // Returns true if the requested range is valid given the stored data.
- bool IsRequestedRangeOK();
- // Returns true if the response headers match what we expect, false otherwise.
- bool ResponseHeadersOK(const HttpResponseHeaders* headers);
- // Fixes the response headers to include the right content length and range.
- // |success| is the result of the whole request so if it's false, we'll change
- // the result code to be 416.
- void FixResponseHeaders(HttpResponseHeaders* headers, bool success);
- // Fixes the content length that we want to store in the cache.
- void FixContentLength(HttpResponseHeaders* headers);
- // Reads up to |data_len| bytes from the cache and stores them in the provided
- // buffer (|data|). Basically, this is just a wrapper around the API of the
- // cache that provides the right arguments for the current range. When the IO
- // operation completes, OnCacheReadCompleted() must be called with the result
- // of the operation.
- int CacheRead(disk_cache::Entry* entry,
- IOBuffer* data,
- int data_len,
- CompletionOnceCallback callback);
- // Writes |data_len| bytes to cache. This is basically a wrapper around the
- // API of the cache that provides the right arguments for the current range.
- int CacheWrite(disk_cache::Entry* entry,
- IOBuffer* data,
- int data_len,
- CompletionOnceCallback callback);
- // This method should be called when CacheRead() finishes the read, to update
- // the internal state about the current range.
- void OnCacheReadCompleted(int result);
- // This method should be called after receiving data from the network, to
- // update the internal state about the current range.
- void OnNetworkReadCompleted(int result);
- bool initial_validation() const { return initial_validation_; }
- bool range_requested() const { return range_requested_; }
- private:
- // Returns the length to use when scanning the cache.
- int GetNextRangeLen();
- // Completion routine for our callback.
- void GetAvailableRangeCompleted(const disk_cache::RangeResult& result);
- // The portion we're trying to get, either from cache or network.
- int64_t current_range_start_ = 0;
- int64_t current_range_end_ = 0;
- // Next portion available in the cache --- this may be what's currently being
- // read, or the next thing that will be read if the current network portion
- // succeeds.
- //
- // |cached_start_| represents the beginning of the range, while
- // |cached_min_len_| the data not yet read (possibly overestimated). It may
- // also have an error code latched into it.
- int64_t cached_start_ = 0;
- int cached_min_len_ = 0;
- // The size of the whole file.
- int64_t resource_size_ = 0;
- HttpByteRange byte_range_; // The range requested by the user.
- // The clean set of extra headers (no ranges).
- HttpRequestHeaders extra_headers_;
- bool range_requested_ = false; // ###
- bool range_present_ = false; // True if next range entry is already stored.
- bool final_range_ = false;
- bool sparse_entry_ = true;
- bool truncated_ = false; // We have an incomplete 200 stored.
- bool initial_validation_ = false; // Only used for truncated entries.
- CompletionOnceCallback callback_;
- base::WeakPtrFactory<PartialData> weak_factory_{this};
- };
- } // namespace net
- #endif // NET_HTTP_PARTIAL_DATA_H_
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