1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
|
// Copyright 2017 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 CONTENT_BROWSER_DOWNLOAD_PARALLEL_DOWNLOAD_UTILS_H_
#define CONTENT_BROWSER_DOWNLOAD_PARALLEL_DOWNLOAD_UTILS_H_
#include <vector>
#include "components/download/public/common/download_create_info.h"
#include "components/download/public/common/download_item.h"
#include "content/browser/download/download_file_impl.h"
#include "content/common/content_export.h"
namespace content {
// Finch parameter key value to enable parallel download. Used in enabled
// experiment group that needs other parameters, such as min_slice_size, but
// don't want to actually do parallel download.
constexpr char kEnableParallelDownloadFinchKey[] = "enable_parallel_download";
// Finch parameter key value for minimum slice size in bytes to use parallel
// download.
constexpr char kMinSliceSizeFinchKey[] = "min_slice_size";
// Finch parameter key value for number of parallel requests in a parallel
// download, including the original request.
constexpr char kParallelRequestCountFinchKey[] = "request_count";
// Finch parameter key value for the delay time in milliseconds to send
// parallel requests after response of the original request is handled.
constexpr char kParallelRequestDelayFinchKey[] = "parallel_request_delay";
// Finch parameter key value for the remaining time in seconds that is required
// to send parallel requests.
constexpr char kParallelRequestRemainingTimeFinchKey[] =
"parallel_request_remaining_time";
// Chunks the content that starts from |current_offset|, into at most
// std::max(|request_count|, 1) smaller slices.
// Each slice contains at least |min_slice_size| bytes unless |total_length|
// is less than |min_slice_size|.
// The last slice is half opened.
CONTENT_EXPORT std::vector<download::DownloadItem::ReceivedSlice>
FindSlicesForRemainingContent(int64_t current_offset,
int64_t total_length,
int request_count,
int64_t min_slice_size);
// Given an array of slices that are received, returns an array of slices to
// download. |received_slices| must be ordered by offsets.
CONTENT_EXPORT std::vector<download::DownloadItem::ReceivedSlice>
FindSlicesToDownload(
const std::vector<download::DownloadItem::ReceivedSlice>& received_slices);
// Adds or merges a new received slice into a vector of sorted slices. If the
// slice can be merged with the slice preceding it, merge the 2 slices.
// Otherwise, insert the slice and keep the vector sorted. Returns the index
// of the newly updated slice.
CONTENT_EXPORT size_t AddOrMergeReceivedSliceIntoSortedArray(
const download::DownloadItem::ReceivedSlice& new_slice,
std::vector<download::DownloadItem::ReceivedSlice>& received_slices);
// Returns if a preceding stream can still download the part of content that
// was arranged to |error_stream|.
CONTENT_EXPORT bool CanRecoverFromError(
const DownloadFileImpl::SourceStream* error_stream,
const DownloadFileImpl::SourceStream* preceding_neighbor);
// Finch configuration utilities.
//
// Get the minimum slice size to use parallel download from finch configuration.
// A slice won't be further chunked into smaller slices if the size is less
// than the minimum size.
CONTENT_EXPORT int64_t GetMinSliceSizeConfig();
// Get the request count for parallel download from finch configuration.
CONTENT_EXPORT int GetParallelRequestCountConfig();
// Get the time delay to send parallel requests after the response of original
// request is handled.
CONTENT_EXPORT base::TimeDelta GetParallelRequestDelayConfig();
// Get the required remaining time before creating parallel requests.
CONTENT_EXPORT base::TimeDelta GetParallelRequestRemainingTimeConfig();
// Print the states of received slices for debugging.
CONTENT_EXPORT void DebugSlicesInfo(
const download::DownloadItem::ReceivedSlices& slices);
// Given an ordered array of slices, get the maximum size of a contiguous data
// block that starts from offset 0. If the first slice doesn't start from offset
// 0, return 0.
CONTENT_EXPORT int64_t GetMaxContiguousDataBlockSizeFromBeginning(
const download::DownloadItem::ReceivedSlices& slices);
// Returns whether parallel download is enabled.
CONTENT_EXPORT bool IsParallelDownloadEnabled();
} // namespace content
#endif // CONTENT_BROWSER_DOWNLOAD_PARALLEL_DOWNLOAD_UTILS_H_
|
