OpenShot Library | libopenshot 0.2.7
CacheDisk.h
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1/**
2 * @file
3 * @brief Header file for CacheDisk class
4 * @author Jonathan Thomas <jonathan@openshot.org>
5 *
6 * @ref License
7 */
8
9/* LICENSE
10 *
11 * Copyright (c) 2008-2019 OpenShot Studios, LLC
12 * <http://www.openshotstudios.com/>. This file is part of
13 * OpenShot Library (libopenshot), an open-source project dedicated to
14 * delivering high quality video editing and animation solutions to the
15 * world. For more information visit <http://www.openshot.org/>.
16 *
17 * OpenShot Library (libopenshot) is free software: you can redistribute it
18 * and/or modify it under the terms of the GNU Lesser General Public License
19 * as published by the Free Software Foundation, either version 3 of the
20 * License, or (at your option) any later version.
21 *
22 * OpenShot Library (libopenshot) is distributed in the hope that it will be
23 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU Lesser General Public License for more details.
26 *
27 * You should have received a copy of the GNU Lesser General Public License
28 * along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
29 */
30
31#ifndef OPENSHOT_CACHE_DISK_H
32#define OPENSHOT_CACHE_DISK_H
33
34#include <map>
35#include <deque>
36#include <memory>
37#include "CacheBase.h"
38#include "Frame.h"
39#include <QDir>
40
41namespace openshot {
42
43 /**
44 * @brief This class is a disk-based cache manager for Frame objects.
45 *
46 * It is used by the Timeline class, if enabled, to cache video and audio frames to disk, to cut down on CPU
47 * and memory utilization. This will thrash a user's disk, but save their memory and CPU. It's a trade off that
48 * sometimes makes perfect sense. You can also set the max number of bytes to cache.
49 */
50 class CacheDisk : public CacheBase {
51 private:
52 QDir path; ///< This is the folder path of the cache directory
53 std::map<int64_t, int64_t> frames; ///< This map holds the frame number and Frame objects
54 std::deque<int64_t> frame_numbers; ///< This queue holds a sequential list of cached Frame numbers
55 std::string image_format;
56 float image_quality;
57 float image_scale;
58
59 int64_t frame_size_bytes; ///< The size of the cached frame in bytes
60 bool needs_range_processing; ///< Something has changed, and the range data needs to be re-calculated
61 std::string json_ranges; ///< JSON ranges of frame numbers
62 std::vector<int64_t> ordered_frame_numbers; ///< Ordered list of frame numbers used by cache
63 std::map<int64_t, int64_t> frame_ranges; ///< This map holds the ranges of frames, useful for quickly displaying the contents of the cache
64 int64_t range_version; ///< The version of the JSON range data (incremented with each change)
65
66 /// Clean up cached frames that exceed the max number of bytes
67 void CleanUp();
68
69 /// Init path directory
70 void InitPath(std::string cache_path);
71
72 /// Calculate ranges of frames
73 void CalculateRanges();
74
75 public:
76 /// @brief Default constructor, no max bytes
77 /// @param cache_path The folder path of the cache directory (empty string = /tmp/preview-cache/)
78 /// @param format The image format for disk caching (ppm, jpg, png)
79 /// @param quality The quality of the image (1.0=highest quality/slowest speed, 0.0=worst quality/fastest speed)
80 /// @param scale The scale factor for the preview images (1.0 = original size, 0.5=half size, 0.25=quarter size, etc...)
81 CacheDisk(std::string cache_path, std::string format, float quality, float scale);
82
83 /// @brief Constructor that sets the max bytes to cache
84 /// @param cache_path The folder path of the cache directory (empty string = /tmp/preview-cache/)
85 /// @param format The image format for disk caching (ppm, jpg, png)
86 /// @param quality The quality of the image (1.0=highest quality/slowest speed, 0.0=worst quality/fastest speed)
87 /// @param scale The scale factor for the preview images (1.0 = original size, 0.5=half size, 0.25=quarter size, etc...)
88 /// @param max_bytes The maximum bytes to allow in the cache. Once exceeded, the cache will purge the oldest frames.
89 CacheDisk(std::string cache_path, std::string format, float quality, float scale, int64_t max_bytes);
90
91 // Default destructor
92 ~CacheDisk();
93
94 /// @brief Add a Frame to the cache
95 /// @param frame The openshot::Frame object needing to be cached.
96 void Add(std::shared_ptr<openshot::Frame> frame);
97
98 /// Clear the cache of all frames
99 void Clear();
100
101 /// Count the frames in the queue
102 int64_t Count();
103
104 /// @brief Get a frame from the cache
105 /// @param frame_number The frame number of the cached frame
106 std::shared_ptr<openshot::Frame> GetFrame(int64_t frame_number);
107
108 /// Gets the maximum bytes value
109 int64_t GetBytes();
110
111 /// Get the smallest frame number
112 std::shared_ptr<openshot::Frame> GetSmallestFrame();
113
114 /// @brief Move frame to front of queue (so it lasts longer)
115 /// @param frame_number The frame number of the cached frame
116 void MoveToFront(int64_t frame_number);
117
118 /// @brief Remove a specific frame
119 /// @param frame_number The frame number of the cached frame
120 void Remove(int64_t frame_number);
121
122 /// @brief Remove a range of frames
123 /// @param start_frame_number The starting frame number of the cached frame
124 /// @param end_frame_number The ending frame number of the cached frame
125 void Remove(int64_t start_frame_number, int64_t end_frame_number);
126
127 // Get and Set JSON methods
128 std::string Json(); ///< Generate JSON string of this object
129 void SetJson(const std::string value); ///< Load JSON string into this object
130 Json::Value JsonValue(); ///< Generate Json::Value for this object
131 void SetJsonValue(const Json::Value root); ///< Load Json::Value into this object
132 };
133
134}
135
136#endif
Header file for CacheBase class.
Header file for Frame class.
All cache managers in libopenshot are based on this CacheBase class.
Definition: CacheBase.h:49
int64_t max_bytes
This is the max number of bytes to cache (0 = no limit)
Definition: CacheBase.h:52
This class is a disk-based cache manager for Frame objects.
Definition: CacheDisk.h:50
std::shared_ptr< openshot::Frame > GetFrame(int64_t frame_number)
Get a frame from the cache.
Definition: CacheDisk.cpp:223
CacheDisk(std::string cache_path, std::string format, float quality, float scale)
Default constructor, no max bytes.
Definition: CacheDisk.cpp:42
void MoveToFront(int64_t frame_number)
Move frame to front of queue (so it lasts longer)
Definition: CacheDisk.cpp:386
std::string Json()
Generate JSON string of this object.
Definition: CacheDisk.cpp:463
void Add(std::shared_ptr< openshot::Frame > frame)
Add a Frame to the cache.
Definition: CacheDisk.cpp:164
std::shared_ptr< openshot::Frame > GetSmallestFrame()
Get the smallest frame number.
Definition: CacheDisk.cpp:293
Json::Value JsonValue()
Generate Json::Value for this object.
Definition: CacheDisk.cpp:470
void Clear()
Clear the cache of all frames.
Definition: CacheDisk.cpp:412
void SetJsonValue(const Json::Value root)
Load Json::Value into this object.
Definition: CacheDisk.cpp:514
void SetJson(const std::string value)
Load JSON string into this object.
Definition: CacheDisk.cpp:497
int64_t GetBytes()
Gets the maximum bytes value.
Definition: CacheDisk.cpp:315
int64_t Count()
Count the frames in the queue.
Definition: CacheDisk.cpp:433
void Remove(int64_t frame_number)
Remove a specific frame.
Definition: CacheDisk.cpp:331
This namespace is the default namespace for all code in the openshot library.
Definition: Compressor.h:47