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1 /*
2  * Copyright 2017 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 /**
18  * @file hardware_buffer.h
19  * @brief API for native hardware buffers.
20  */
21 /**
22  * @defgroup AHardwareBuffer Native Hardware Buffer
23  *
24  * AHardwareBuffer objects represent chunks of memory that can be
25  * accessed by various hardware components in the system. It can be
26  * easily converted to the Java counterpart
27  * android.hardware.HardwareBuffer and passed between processes using
28  * Binder. All operations involving AHardwareBuffer and HardwareBuffer
29  * are zero-copy, i.e., passing AHardwareBuffer to another process
30  * creates a shared view of the same region of memory.
31  *
32  * AHardwareBuffers can be bound to EGL/OpenGL and Vulkan primitives.
33  * For EGL, use the extension function eglGetNativeClientBufferANDROID
34  * to obtain an EGLClientBuffer and pass it directly to
35  * eglCreateImageKHR. Refer to the EGL extensions
36  * EGL_ANDROID_get_native_client_buffer and
37  * EGL_ANDROID_image_native_buffer for more information. In Vulkan,
38  * the contents of the AHardwareBuffer can be accessed as external
39  * memory. See the VK_ANDROID_external_memory_android_hardware_buffer
40  * extension for details.
41  *
42  * @{
43  */
44 
45 #ifndef ANDROID_HARDWARE_BUFFER_H
46 #define ANDROID_HARDWARE_BUFFER_H
47 
48 #include <android/rect.h>
49 #include <inttypes.h>
50 #include <sys/cdefs.h>
51 
52 __BEGIN_DECLS
53 
54 // clang-format off
55 
56 /**
57  * Buffer pixel formats.
58  */
59 enum AHardwareBuffer_Format {
60     /**
61      * Corresponding formats:
62      *   Vulkan: VK_FORMAT_R8G8B8A8_UNORM
63      *   OpenGL ES: GL_RGBA8
64      */
65     AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM           = 1,
66 
67     /**
68      * 32 bits per pixel, 8 bits per channel format where alpha values are
69      * ignored (always opaque).
70      * Corresponding formats:
71      *   Vulkan: VK_FORMAT_R8G8B8A8_UNORM
72      *   OpenGL ES: GL_RGB8
73      */
74     AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM           = 2,
75 
76     /**
77      * Corresponding formats:
78      *   Vulkan: VK_FORMAT_R8G8B8_UNORM
79      *   OpenGL ES: GL_RGB8
80      */
81     AHARDWAREBUFFER_FORMAT_R8G8B8_UNORM             = 3,
82 
83     /**
84      * Corresponding formats:
85      *   Vulkan: VK_FORMAT_R5G6B5_UNORM_PACK16
86      *   OpenGL ES: GL_RGB565
87      */
88     AHARDWAREBUFFER_FORMAT_R5G6B5_UNORM             = 4,
89 
90     /**
91      * Corresponding formats:
92      *   Vulkan: VK_FORMAT_R16G16B16A16_SFLOAT
93      *   OpenGL ES: GL_RGBA16F
94      */
95     AHARDWAREBUFFER_FORMAT_R16G16B16A16_FLOAT       = 0x16,
96 
97     /**
98      * Corresponding formats:
99      *   Vulkan: VK_FORMAT_A2B10G10R10_UNORM_PACK32
100      *   OpenGL ES: GL_RGB10_A2
101      */
102     AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM        = 0x2b,
103 
104     /**
105      * Opaque binary blob format.
106      * Must have height 1 and one layer, with width equal to the buffer
107      * size in bytes. Corresponds to Vulkan buffers and OpenGL buffer
108      * objects. Can be bound to the latter using GL_EXT_external_buffer.
109      */
110     AHARDWAREBUFFER_FORMAT_BLOB                     = 0x21,
111 
112     /**
113      * Corresponding formats:
114      *   Vulkan: VK_FORMAT_D16_UNORM
115      *   OpenGL ES: GL_DEPTH_COMPONENT16
116      */
117     AHARDWAREBUFFER_FORMAT_D16_UNORM                = 0x30,
118 
119     /**
120      * Corresponding formats:
121      *   Vulkan: VK_FORMAT_X8_D24_UNORM_PACK32
122      *   OpenGL ES: GL_DEPTH_COMPONENT24
123      */
124     AHARDWAREBUFFER_FORMAT_D24_UNORM                = 0x31,
125 
126     /**
127      * Corresponding formats:
128      *   Vulkan: VK_FORMAT_D24_UNORM_S8_UINT
129      *   OpenGL ES: GL_DEPTH24_STENCIL8
130      */
131     AHARDWAREBUFFER_FORMAT_D24_UNORM_S8_UINT        = 0x32,
132 
133     /**
134      * Corresponding formats:
135      *   Vulkan: VK_FORMAT_D32_SFLOAT
136      *   OpenGL ES: GL_DEPTH_COMPONENT32F
137      */
138     AHARDWAREBUFFER_FORMAT_D32_FLOAT                = 0x33,
139 
140     /**
141      * Corresponding formats:
142      *   Vulkan: VK_FORMAT_D32_SFLOAT_S8_UINT
143      *   OpenGL ES: GL_DEPTH32F_STENCIL8
144      */
145     AHARDWAREBUFFER_FORMAT_D32_FLOAT_S8_UINT        = 0x34,
146 
147     /**
148      * Corresponding formats:
149      *   Vulkan: VK_FORMAT_S8_UINT
150      *   OpenGL ES: GL_STENCIL_INDEX8
151      */
152     AHARDWAREBUFFER_FORMAT_S8_UINT                  = 0x35,
153 
154     /**
155      * YUV 420 888 format.
156      * Must have an even width and height. Can be accessed in OpenGL
157      * shaders through an external sampler. Does not support mip-maps
158      * cube-maps or multi-layered textures.
159      */
160     AHARDWAREBUFFER_FORMAT_Y8Cb8Cr8_420             = 0x23,
161 
162     /**
163      * YUV P010 format.
164      * Must have an even width and height. Can be accessed in OpenGL
165      * shaders through an external sampler. Does not support mip-maps
166      * cube-maps or multi-layered textures.
167      */
168     AHARDWAREBUFFER_FORMAT_YCbCr_P010               = 0x36,
169 
170     /**
171      * Corresponding formats:
172      *   Vulkan: VK_FORMAT_R8_UNORM
173      *   OpenGL ES: GR_GL_R8
174      */
175     AHARDWAREBUFFER_FORMAT_R8_UNORM                 = 0x38,
176 };
177 
178 /**
179  * Buffer usage flags, specifying how the buffer will be accessed.
180  */
181 enum AHardwareBuffer_UsageFlags {
182     /**
183      * The buffer will never be locked for direct CPU reads using the
184      * AHardwareBuffer_lock() function. Note that reading the buffer
185      * using OpenGL or Vulkan functions or memory mappings is still
186      * allowed.
187      */
188     AHARDWAREBUFFER_USAGE_CPU_READ_NEVER        = 0UL,
189     /**
190      * The buffer will sometimes be locked for direct CPU reads using
191      * the AHardwareBuffer_lock() function. Note that reading the
192      * buffer using OpenGL or Vulkan functions or memory mappings
193      * does not require the presence of this flag.
194      */
195     AHARDWAREBUFFER_USAGE_CPU_READ_RARELY       = 2UL,
196     /**
197      * The buffer will often be locked for direct CPU reads using
198      * the AHardwareBuffer_lock() function. Note that reading the
199      * buffer using OpenGL or Vulkan functions or memory mappings
200      * does not require the presence of this flag.
201      */
202     AHARDWAREBUFFER_USAGE_CPU_READ_OFTEN        = 3UL,
203 
204     /** CPU read value mask. */
205     AHARDWAREBUFFER_USAGE_CPU_READ_MASK         = 0xFUL,
206     /**
207      * The buffer will never be locked for direct CPU writes using the
208      * AHardwareBuffer_lock() function. Note that writing the buffer
209      * using OpenGL or Vulkan functions or memory mappings is still
210      * allowed.
211      */
212     AHARDWAREBUFFER_USAGE_CPU_WRITE_NEVER       = 0UL << 4,
213     /**
214      * The buffer will sometimes be locked for direct CPU writes using
215      * the AHardwareBuffer_lock() function. Note that writing the
216      * buffer using OpenGL or Vulkan functions or memory mappings
217      * does not require the presence of this flag.
218      */
219     AHARDWAREBUFFER_USAGE_CPU_WRITE_RARELY      = 2UL << 4,
220     /**
221      * The buffer will often be locked for direct CPU writes using
222      * the AHardwareBuffer_lock() function. Note that writing the
223      * buffer using OpenGL or Vulkan functions or memory mappings
224      * does not require the presence of this flag.
225      */
226     AHARDWAREBUFFER_USAGE_CPU_WRITE_OFTEN       = 3UL << 4,
227     /** CPU write value mask. */
228     AHARDWAREBUFFER_USAGE_CPU_WRITE_MASK        = 0xFUL << 4,
229     /** The buffer will be read from by the GPU as a texture. */
230     AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE     = 1UL << 8,
231     /** The buffer will be written to by the GPU as a framebuffer attachment.*/
232     AHARDWAREBUFFER_USAGE_GPU_FRAMEBUFFER       = 1UL << 9,
233     /**
234      * The buffer will be written to by the GPU as a framebuffer
235      * attachment.
236      *
237      * Note that the name of this flag is somewhat misleading: it does
238      * not imply that the buffer contains a color format. A buffer with
239      * depth or stencil format that will be used as a framebuffer
240      * attachment should also have this flag. Use the equivalent flag
241      * AHARDWAREBUFFER_USAGE_GPU_FRAMEBUFFER to avoid this confusion.
242      */
243     AHARDWAREBUFFER_USAGE_GPU_COLOR_OUTPUT      = AHARDWAREBUFFER_USAGE_GPU_FRAMEBUFFER,
244     /**
245      * The buffer will be used as a composer HAL overlay layer.
246      *
247      * This flag is currently only needed when using ASurfaceTransaction_setBuffer
248      * to set a buffer. In all other cases, the framework adds this flag
249      * internally to buffers that could be presented in a composer overlay.
250      * ASurfaceTransaction_setBuffer is special because it uses buffers allocated
251      * directly through AHardwareBuffer_allocate instead of buffers allocated
252      * by the framework.
253      */
254     AHARDWAREBUFFER_USAGE_COMPOSER_OVERLAY      = 1ULL << 11,
255     /**
256      * The buffer is protected from direct CPU access or being read by
257      * non-secure hardware, such as video encoders.
258      *
259      * This flag is incompatible with CPU read and write flags. It is
260      * mainly used when handling DRM video. Refer to the EGL extension
261      * EGL_EXT_protected_content and GL extension
262      * GL_EXT_protected_textures for more information on how these
263      * buffers are expected to behave.
264      */
265     AHARDWAREBUFFER_USAGE_PROTECTED_CONTENT     = 1UL << 14,
266     /** The buffer will be read by a hardware video encoder. */
267     AHARDWAREBUFFER_USAGE_VIDEO_ENCODE          = 1UL << 16,
268     /**
269      * The buffer will be used for direct writes from sensors.
270      * When this flag is present, the format must be AHARDWAREBUFFER_FORMAT_BLOB.
271      */
272     AHARDWAREBUFFER_USAGE_SENSOR_DIRECT_DATA    = 1UL << 23,
273     /**
274      * The buffer will be used as a shader storage or uniform buffer object.
275      * When this flag is present, the format must be AHARDWAREBUFFER_FORMAT_BLOB.
276      */
277     AHARDWAREBUFFER_USAGE_GPU_DATA_BUFFER       = 1UL << 24,
278     /**
279      * The buffer will be used as a cube map texture.
280      * When this flag is present, the buffer must have a layer count
281      * that is a multiple of 6. Note that buffers with this flag must be
282      * bound to OpenGL textures using the extension
283      * GL_EXT_EGL_image_storage instead of GL_KHR_EGL_image.
284      */
285     AHARDWAREBUFFER_USAGE_GPU_CUBE_MAP          = 1UL << 25,
286     /**
287      * The buffer contains a complete mipmap hierarchy.
288      * Note that buffers with this flag must be bound to OpenGL textures using
289      * the extension GL_EXT_EGL_image_storage instead of GL_KHR_EGL_image.
290      */
291     AHARDWAREBUFFER_USAGE_GPU_MIPMAP_COMPLETE   = 1UL << 26,
292 
293     AHARDWAREBUFFER_USAGE_VENDOR_0  = 1ULL << 28,
294     AHARDWAREBUFFER_USAGE_VENDOR_1  = 1ULL << 29,
295     AHARDWAREBUFFER_USAGE_VENDOR_2  = 1ULL << 30,
296     AHARDWAREBUFFER_USAGE_VENDOR_3  = 1ULL << 31,
297     AHARDWAREBUFFER_USAGE_VENDOR_4  = 1ULL << 48,
298     AHARDWAREBUFFER_USAGE_VENDOR_5  = 1ULL << 49,
299     AHARDWAREBUFFER_USAGE_VENDOR_6  = 1ULL << 50,
300     AHARDWAREBUFFER_USAGE_VENDOR_7  = 1ULL << 51,
301     AHARDWAREBUFFER_USAGE_VENDOR_8  = 1ULL << 52,
302     AHARDWAREBUFFER_USAGE_VENDOR_9  = 1ULL << 53,
303     AHARDWAREBUFFER_USAGE_VENDOR_10 = 1ULL << 54,
304     AHARDWAREBUFFER_USAGE_VENDOR_11 = 1ULL << 55,
305     AHARDWAREBUFFER_USAGE_VENDOR_12 = 1ULL << 56,
306     AHARDWAREBUFFER_USAGE_VENDOR_13 = 1ULL << 57,
307     AHARDWAREBUFFER_USAGE_VENDOR_14 = 1ULL << 58,
308     AHARDWAREBUFFER_USAGE_VENDOR_15 = 1ULL << 59,
309     AHARDWAREBUFFER_USAGE_VENDOR_16 = 1ULL << 60,
310     AHARDWAREBUFFER_USAGE_VENDOR_17 = 1ULL << 61,
311     AHARDWAREBUFFER_USAGE_VENDOR_18 = 1ULL << 62,
312     AHARDWAREBUFFER_USAGE_VENDOR_19 = 1ULL << 63,
313 };
314 
315 /**
316  * Buffer description. Used for allocating new buffers and querying
317  * parameters of existing ones.
318  */
319 typedef struct AHardwareBuffer_Desc {
320     uint32_t width;  ///< Width in pixels.
321     uint32_t height; ///< Height in pixels.
322     /**
323      * Number of images in an image array. AHardwareBuffers with one
324      * layer correspond to regular 2D textures. AHardwareBuffers with
325      * more than layer correspond to texture arrays. If the layer count
326      * is a multiple of 6 and the usage flag
327      * AHARDWAREBUFFER_USAGE_GPU_CUBE_MAP is present, the buffer is
328      * a cube map or a cube map array.
329      */
330     uint32_t layers;
331     uint32_t format; ///< One of AHardwareBuffer_Format.
332     uint64_t usage;  ///< Combination of AHardwareBuffer_UsageFlags.
333     uint32_t stride; ///< Row stride in pixels, ignored for AHardwareBuffer_allocate()
334     uint32_t rfu0;   ///< Initialize to zero, reserved for future use.
335     uint64_t rfu1;   ///< Initialize to zero, reserved for future use.
336 } AHardwareBuffer_Desc;
337 
338 /**
339  * Holds data for a single image plane.
340  */
341 typedef struct AHardwareBuffer_Plane {
342     void*    _Nullable data; ///< Points to first byte in plane
343     uint32_t pixelStride;    ///< Distance in bytes from the color channel of one pixel to the next
344     uint32_t rowStride;      ///< Distance in bytes from the first value of one row of the image to
345                              ///  the first value of the next row.
346 } AHardwareBuffer_Plane;
347 
348 /**
349  * Holds all image planes that contain the pixel data.
350  */
351 typedef struct AHardwareBuffer_Planes {
352     uint32_t              planeCount; ///< Number of distinct planes
353     AHardwareBuffer_Plane planes[4];  ///< Array of image planes
354 } AHardwareBuffer_Planes;
355 
356 /**
357  * Opaque handle for a native hardware buffer.
358  */
359 typedef struct AHardwareBuffer AHardwareBuffer;
360 
361 // clang-format on
362 
363 /**
364  * Allocates a buffer that matches the passed AHardwareBuffer_Desc.
365  *
366  * If allocation succeeds, the buffer can be used according to the
367  * usage flags specified in its description. If a buffer is used in ways
368  * not compatible with its usage flags, the results are undefined and
369  * may include program termination.
370  *
371  * Available since API level 26.
372  *
373  * \return 0 on success, or an error number of the allocation fails for
374  * any reason. The returned buffer has a reference count of 1.
375  */
376 int AHardwareBuffer_allocate(const AHardwareBuffer_Desc* _Nonnull desc,
377                              AHardwareBuffer* _Nullable* _Nonnull outBuffer) __INTRODUCED_IN(26);
378 /**
379  * Acquire a reference on the given AHardwareBuffer object.
380  *
381  * This prevents the object from being deleted until the last reference
382  * is removed.
383  *
384  * Available since API level 26.
385  */
386 void AHardwareBuffer_acquire(AHardwareBuffer* _Nonnull buffer) __INTRODUCED_IN(26);
387 
388 /**
389  * Remove a reference that was previously acquired with
390  * AHardwareBuffer_acquire() or AHardwareBuffer_allocate().
391  *
392  * Available since API level 26.
393  */
394 void AHardwareBuffer_release(AHardwareBuffer* _Nonnull buffer) __INTRODUCED_IN(26);
395 
396 /**
397  * Return a description of the AHardwareBuffer in the passed
398  * AHardwareBuffer_Desc struct.
399  *
400  * Available since API level 26.
401  */
402 void AHardwareBuffer_describe(const AHardwareBuffer* _Nonnull buffer,
403                               AHardwareBuffer_Desc* _Nonnull outDesc) __INTRODUCED_IN(26);
404 
405 /**
406  * Lock the AHardwareBuffer for direct CPU access.
407  *
408  * This function can lock the buffer for either reading or writing.
409  * It may block if the hardware needs to finish rendering, if CPU caches
410  * need to be synchronized, or possibly for other implementation-
411  * specific reasons.
412  *
413  * The passed AHardwareBuffer must have one layer, otherwise the call
414  * will fail.
415  *
416  * If \a fence is not negative, it specifies a fence file descriptor on
417  * which to wait before locking the buffer. If it's negative, the caller
418  * is responsible for ensuring that writes to the buffer have completed
419  * before calling this function.  Using this parameter is more efficient
420  * than waiting on the fence and then calling this function.
421  *
422  * The \a usage parameter may only specify AHARDWAREBUFFER_USAGE_CPU_*.
423  * If set, then outVirtualAddress is filled with the address of the
424  * buffer in virtual memory. The flags must also be compatible with
425  * usage flags specified at buffer creation: if a read flag is passed,
426  * the buffer must have been created with
427  * AHARDWAREBUFFER_USAGE_CPU_READ_RARELY or
428  * AHARDWAREBUFFER_USAGE_CPU_READ_OFTEN. If a write flag is passed, it
429  * must have been created with AHARDWAREBUFFER_USAGE_CPU_WRITE_RARELY or
430  * AHARDWAREBUFFER_USAGE_CPU_WRITE_OFTEN.
431  *
432  * If \a rect is not NULL, the caller promises to modify only data in
433  * the area specified by rect. If rect is NULL, the caller may modify
434  * the contents of the entire buffer. The content of the buffer outside
435  * of the specified rect is NOT modified by this call.
436  *
437  * It is legal for several different threads to lock a buffer for read
438  * access; none of the threads are blocked.
439  *
440  * Locking a buffer simultaneously for write or read/write is undefined,
441  * but will neither terminate the process nor block the caller.
442  * AHardwareBuffer_lock may return an error or leave the buffer's
443  * content in an indeterminate state.
444  *
445  * If the buffer has AHARDWAREBUFFER_FORMAT_BLOB, it is legal lock it
446  * for reading and writing in multiple threads and/or processes
447  * simultaneously, and the contents of the buffer behave like shared
448  * memory.
449  *
450  * Available since API level 26.
451  *
452  * \return 0 on success. -EINVAL if \a buffer is NULL, the usage flags
453  * are not a combination of AHARDWAREBUFFER_USAGE_CPU_*, or the buffer
454  * has more than one layer. Error number if the lock fails for any other
455  * reason.
456  */
457 int AHardwareBuffer_lock(AHardwareBuffer* _Nonnull buffer, uint64_t usage, int32_t fence,
458                          const ARect* _Nullable rect, void* _Nullable* _Nonnull outVirtualAddress)
459         __INTRODUCED_IN(26);
460 
461 /**
462  * Unlock the AHardwareBuffer from direct CPU access.
463  *
464  * Must be called after all changes to the buffer are completed by the
465  * caller.  If \a fence is NULL, the function will block until all work
466  * is completed.  Otherwise, \a fence will be set either to a valid file
467  * descriptor or to -1.  The file descriptor will become signaled once
468  * the unlocking is complete and buffer contents are updated.
469  * The caller is responsible for closing the file descriptor once it's
470  * no longer needed.  The value -1 indicates that unlocking has already
471  * completed before the function returned and no further operations are
472  * necessary.
473  *
474  * Available since API level 26.
475  *
476  * \return 0 on success. -EINVAL if \a buffer is NULL. Error number if
477  * the unlock fails for any reason.
478  */
479 int AHardwareBuffer_unlock(AHardwareBuffer* _Nonnull buffer, int32_t* _Nullable fence)
480         __INTRODUCED_IN(26);
481 
482 /**
483  * Send the AHardwareBuffer to an AF_UNIX socket.
484  *
485  * Available since API level 26.
486  *
487  * \return 0 on success, -EINVAL if \a buffer is NULL, or an error
488  * number if the operation fails for any reason.
489  */
490 int AHardwareBuffer_sendHandleToUnixSocket(const AHardwareBuffer* _Nonnull buffer, int socketFd)
491         __INTRODUCED_IN(26);
492 
493 /**
494  * Receive an AHardwareBuffer from an AF_UNIX socket.
495  *
496  * Available since API level 26.
497  *
498  * \return 0 on success, -EINVAL if \a outBuffer is NULL, or an error
499  * number if the operation fails for any reason.
500  */
501 int AHardwareBuffer_recvHandleFromUnixSocket(int socketFd,
502                                              AHardwareBuffer* _Nullable* _Nonnull outBuffer)
503         __INTRODUCED_IN(26);
504 
505 /**
506  * Lock a potentially multi-planar AHardwareBuffer for direct CPU access.
507  *
508  * This function is similar to AHardwareBuffer_lock, but can lock multi-planar
509  * formats. The locked planes are returned in the \a outPlanes argument. Note,
510  * that multi-planar should not be confused with multi-layer images, which this
511  * locking function does not support.
512  *
513  * YUV formats are always represented by three separate planes of data, one for
514  * each color plane. The order of planes in the array is guaranteed such that
515  * plane #0 is always Y, plane #1 is always U (Cb), and plane #2 is always V
516  * (Cr). All other formats are represented by a single plane.
517  *
518  * Additional information always accompanies the buffers, describing the row
519  * stride and the pixel stride for each plane.
520  *
521  * In case the buffer cannot be locked, \a outPlanes will contain zero planes.
522  *
523  * See the AHardwareBuffer_lock documentation for all other locking semantics.
524  *
525  * Available since API level 29.
526  *
527  * \return 0 on success. -EINVAL if \a buffer is NULL, the usage flags
528  * are not a combination of AHARDWAREBUFFER_USAGE_CPU_*, or the buffer
529  * has more than one layer. Error number if the lock fails for any other
530  * reason.
531  */
532 int AHardwareBuffer_lockPlanes(AHardwareBuffer* _Nonnull buffer, uint64_t usage, int32_t fence,
533                                const ARect* _Nullable rect,
534                                AHardwareBuffer_Planes* _Nonnull outPlanes) __INTRODUCED_IN(29);
535 
536 /**
537  * Test whether the given format and usage flag combination is
538  * allocatable.
539  *
540  * If this function returns true, it means that a buffer with the given
541  * description can be allocated on this implementation, unless resource
542  * exhaustion occurs. If this function returns false, it means that the
543  * allocation of the given description will never succeed.
544  *
545  * The return value of this function may depend on all fields in the
546  * description, except stride, which is always ignored. For example,
547  * some implementations have implementation-defined limits on texture
548  * size and layer count.
549  *
550  * Available since API level 29.
551  *
552  * \return 1 if the format and usage flag combination is allocatable,
553  *     0 otherwise.
554  */
555 int AHardwareBuffer_isSupported(const AHardwareBuffer_Desc* _Nonnull desc) __INTRODUCED_IN(29);
556 
557 /**
558  * Lock an AHardwareBuffer for direct CPU access.
559  *
560  * This function is the same as the above lock function, but passes back
561  * additional information about the bytes per pixel and the bytes per stride
562  * of the locked buffer.  If the bytes per pixel or bytes per stride are unknown
563  * or variable, or if the underlying mapper implementation does not support returning
564  * additional information, then this call will fail with INVALID_OPERATION
565  *
566  * Available since API level 29.
567  */
568 int AHardwareBuffer_lockAndGetInfo(AHardwareBuffer* _Nonnull buffer, uint64_t usage, int32_t fence,
569                                    const ARect* _Nullable rect,
570                                    void* _Nullable* _Nonnull outVirtualAddress,
571                                    int32_t* _Nonnull outBytesPerPixel,
572                                    int32_t* _Nonnull outBytesPerStride) __INTRODUCED_IN(29);
573 
574 
575 /**
576  * Get the system wide unique id for an AHardwareBuffer.
577  *
578  * Available since API level 31.
579  *
580  * \return 0 on success, -EINVAL if \a buffer or \a outId is NULL, or an error number if the
581  * operation fails for any reason.
582  */
583 int AHardwareBuffer_getId(const AHardwareBuffer* _Nonnull buffer, uint64_t* _Nonnull outId)
584         __INTRODUCED_IN(31);
585 
586 __END_DECLS
587 
588 #endif // ANDROID_HARDWARE_BUFFER_H
589 
590 /** @} */
591