CameraMetadata.h revision e7ee7637747371635a85fedd24d2190bb1f38651 
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_CLIENT_CAMERA2_CAMERAMETADATA_CPP
18#define ANDROID_CLIENT_CAMERA2_CAMERAMETADATA_CPP
19
20#include "system/camera_metadata.h"
21#include <utils/String8.h>
22#include <utils/Vector.h>
23
24namespace android {
25class Parcel;
26
27/**
28 * A convenience wrapper around the C-based camera_metadata_t library.
29 */
30class CameraMetadata {
31  public:
32    /** Creates an empty object; best used when expecting to acquire contents
33     * from elsewhere */
34    CameraMetadata();
35    /** Creates an object with space for entryCapacity entries, with
36     * dataCapacity extra storage */
37    CameraMetadata(size_t entryCapacity, size_t dataCapacity = 10);
38
39    ~CameraMetadata();
40
41    /** Takes ownership of passed-in buffer */
42    CameraMetadata(camera_metadata_t *buffer);
43    /** Clones the metadata */
44    CameraMetadata(const CameraMetadata &other);
45
46    /**
47     * Assignment clones metadata buffer.
48     */
49    CameraMetadata &operator=(const CameraMetadata &other);
50    CameraMetadata &operator=(const camera_metadata_t *buffer);
51
52    /**
53     * Get reference to the underlying metadata buffer. Ownership remains with
54     * the CameraMetadata object, but non-const CameraMetadata methods will not
55     * work until unlock() is called. Note that the lock has nothing to do with
56     * thread-safety, it simply prevents the camera_metadata_t pointer returned
57     * here from being accidentally invalidated by CameraMetadata operations.
58     */
59    const camera_metadata_t* getAndLock();
60
61    /**
62     * Unlock the CameraMetadata for use again. After this unlock, the pointer
63     * given from getAndLock() may no longer be used. The pointer passed out
64     * from getAndLock must be provided to guarantee that the right object is
65     * being unlocked.
66     */
67    status_t unlock(const camera_metadata_t *buffer);
68
69    /**
70     * Release a raw metadata buffer to the caller. After this call,
71     * CameraMetadata no longer references the buffer, and the caller takes
72     * responsibility for freeing the raw metadata buffer (using
73     * free_camera_metadata()), or for handing it to another CameraMetadata
74     * instance.
75     */
76    camera_metadata_t* release();
77
78    /**
79     * Clear the metadata buffer and free all storage used by it
80     */
81    void clear();
82
83    /**
84     * Acquire a raw metadata buffer from the caller. After this call,
85     * the caller no longer owns the raw buffer, and must not free or manipulate it.
86     * If CameraMetadata already contains metadata, it is freed.
87     */
88    void acquire(camera_metadata_t* buffer);
89
90    /**
91     * Acquires raw buffer from other CameraMetadata object. After the call, the argument
92     * object no longer has any metadata.
93     */
94    void acquire(CameraMetadata &other);
95
96    /**
97     * Append metadata from another CameraMetadata object.
98     */
99    status_t append(const CameraMetadata &other);
100
101    /**
102     * Number of metadata entries.
103     */
104    size_t entryCount() const;
105
106    /**
107     * Is the buffer empty (no entires)
108     */
109    bool isEmpty() const;
110
111    /**
112     * Sort metadata buffer for faster find
113     */
114    status_t sort();
115
116    /**
117     * Update metadata entry. Will create entry if it doesn't exist already, and
118     * will reallocate the buffer if insufficient space exists. Overloaded for
119     * the various types of valid data.
120     */
121    status_t update(uint32_t tag,
122            const uint8_t *data, size_t data_count);
123    status_t update(uint32_t tag,
124            const int32_t *data, size_t data_count);
125    status_t update(uint32_t tag,
126            const float *data, size_t data_count);
127    status_t update(uint32_t tag,
128            const int64_t *data, size_t data_count);
129    status_t update(uint32_t tag,
130            const double *data, size_t data_count);
131    status_t update(uint32_t tag,
132            const camera_metadata_rational_t *data, size_t data_count);
133    status_t update(uint32_t tag,
134            const String8 &string);
135
136    template<typename T>
137    status_t update(uint32_t tag, Vector<T> data) {
138        return update(tag, data.array(), data.size());
139    }
140
141    /**
142     * Check if a metadata entry exists for a given tag id
143     *
144     */
145    bool exists(uint32_t tag) const;
146
147    /**
148     * Get metadata entry by tag id
149     */
150    camera_metadata_entry find(uint32_t tag);
151
152    /**
153     * Get metadata entry by tag id, with no editing
154     */
155    camera_metadata_ro_entry find(uint32_t tag) const;
156
157    /**
158     * Delete metadata entry by tag
159     */
160    status_t erase(uint32_t tag);
161
162    /**
163     * Swap the underlying camera metadata between this and the other
164     * metadata object.
165     */
166    void swap(CameraMetadata &other);
167
168    /**
169     * Dump contents into FD for debugging. The verbosity levels are
170     * 0: Tag entry information only, no data values
171     * 1: Level 0 plus at most 16 data values per entry
172     * 2: All information
173     *
174     * The indentation parameter sets the number of spaces to add to the start
175     * each line of output.
176     */
177    void dump(int fd, int verbosity = 1, int indentation = 0) const;
178
179    /**
180     * Serialization over Binder
181     */
182
183    // Metadata object is unchanged when reading from parcel fails.
184    status_t readFromParcel(Parcel *parcel);
185    status_t writeToParcel(Parcel *parcel) const;
186
187    /**
188      * Caller becomes the owner of the new metadata
189      * 'const Parcel' doesnt prevent us from calling the read functions.
190      *  which is interesting since it changes the internal state
191      *
192      * NULL can be returned when no metadata was sent, OR if there was an issue
193      * unpacking the serialized data (i.e. bad parcel or invalid structure).
194      */
195    static status_t readFromParcel(const Parcel &parcel,
196                                   camera_metadata_t** out);
197    /**
198      * Caller retains ownership of metadata
199      * - Write 2 (int32 + blob) args in the current position
200      */
201    static status_t writeToParcel(Parcel &parcel,
202                                  const camera_metadata_t* metadata);
203
204  private:
205    camera_metadata_t *mBuffer;
206    bool               mLocked;
207
208    /**
209     * Check if tag has a given type
210     */
211    status_t checkType(uint32_t tag, uint8_t expectedType);
212
213    /**
214     * Base update entry method
215     */
216    status_t updateImpl(uint32_t tag, const void *data, size_t data_count);
217
218    /**
219     * Resize metadata buffer if needed by reallocating it and copying it over.
220     */
221    status_t resizeIfNeeded(size_t extraEntries, size_t extraData);
222
223};
224
225}; // namespace android
226
227#endif
228