OpenShot Library | libopenshot  0.1.9
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  * @section LICENSE
7  *
8  * Copyright (c) 2008-2014 OpenShot Studios, LLC
9  * <http://www.openshotstudios.com/>. This file is part of
10  * OpenShot Library (libopenshot), an open-source project dedicated to
11  * delivering high quality video editing and animation solutions to the
12  * world. For more information visit <http://www.openshot.org/>.
13  *
14  * OpenShot Library (libopenshot) is free software: you can redistribute it
15  * and/or modify it under the terms of the GNU Lesser General Public License
16  * as published by the Free Software Foundation, either version 3 of the
17  * License, or (at your option) any later version.
18  *
19  * OpenShot Library (libopenshot) is distributed in the hope that it will be
20  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22  * GNU Lesser General Public License for more details.
23  *
24  * You should have received a copy of the GNU Lesser General Public License
25  * along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
26  */
27 
28 #ifndef OPENSHOT_CACHE_DISK_H
29 #define OPENSHOT_CACHE_DISK_H
30 
31 #include <map>
32 #include <deque>
33 #include <memory>
34 #include "CacheBase.h"
35 #include "Frame.h"
36 #include "Exceptions.h"
37 #include <QDir>
38 #include <QString>
39 #include <QTextStream>
40 
41 namespace 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  map<int64_t, int64_t> frames; ///< This map holds the frame number and Frame objects
54  deque<int64_t> frame_numbers; ///< This queue holds a sequential list of cached Frame numbers
55  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  string json_ranges; ///< JSON ranges of frame numbers
62  vector<int64_t> ordered_frame_numbers; ///< Ordered list of frame numbers used by cache
63  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(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(string cache_path, 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(string cache_path, 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<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<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<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  string Json(); ///< Generate JSON string of this object
129  void SetJson(string value); ///< Load JSON string into this object
130  Json::Value JsonValue(); ///< Generate Json::JsonValue for this object
131  void SetJsonValue(Json::Value root); ///< Load Json::JsonValue into this object
132  };
133 
134 }
135 
136 #endif
void Add(std::shared_ptr< Frame > frame)
Add a Frame to the cache.
Definition: CacheDisk.cpp:166
int64_t Count()
Count the frames in the queue.
Definition: CacheDisk.cpp:435
This class is a disk-based cache manager for Frame objects.
Definition: CacheDisk.h:50
int64_t GetBytes()
Gets the maximum bytes value.
Definition: CacheDisk.cpp:317
void SetJsonValue(Json::Value root)
Load Json::JsonValue into this object.
Definition: CacheDisk.cpp:522
Header file for CacheBase class.
Header file for all Exception classes.
std::shared_ptr< Frame > GetFrame(int64_t frame_number)
Get a frame from the cache.
Definition: CacheDisk.cpp:225
Header file for Frame class.
void Remove(int64_t frame_number)
Remove a specific frame.
Definition: CacheDisk.cpp:333
Json::Value JsonValue()
Generate Json::JsonValue for this object.
Definition: CacheDisk.cpp:472
void MoveToFront(int64_t frame_number)
Move frame to front of queue (so it lasts longer)
Definition: CacheDisk.cpp:388
All cache managers in libopenshot are based on this CacheBase class.
Definition: CacheBase.h:45
void Clear()
Clear the cache of all frames.
Definition: CacheDisk.cpp:414
This namespace is the default namespace for all code in the openshot library.
CacheDisk(string cache_path, string format, float quality, float scale)
Default constructor, no max bytes.
Definition: CacheDisk.cpp:34
std::shared_ptr< Frame > GetSmallestFrame()
Get the smallest frame number.
Definition: CacheDisk.cpp:295
void SetJson(string value)
Load JSON string into this object.
Definition: CacheDisk.cpp:499
int64_t max_bytes
This is the max number of bytes to cache (0 = no limit)
Definition: CacheBase.h:49
string Json()
Get and Set JSON methods.
Definition: CacheDisk.cpp:465