1 /* GStreamer 2 * Copyright (C) <2009> Collabora Ltd 3 * @author: Olivier Crete <olivier.crete@collabora.co.uk 4 * Copyright (C) <2009> Nokia Inc 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 25 /* 26 * None of this code is thread safe, if you want to use it in a 27 * multi-threaded context, please protect it with a mutex. 28 * 29 * First, create a writer with sp_writer_create(), then select() on 30 * the socket returned by sp_get_fd(). If the socket is closed or any 31 * function returns an error, the app should call sp_close() and 32 * assume the other side is dead. The writer calls 33 * sp_writer_accept_client() when there is something to read from the 34 * main server fd. This returns a new ShmClient (representing a client 35 * connection), the writer needs to do a select() on the socket 36 * returned by sp_writer_get_client_fd(). If it gets an error on that 37 * socket, it calls sp_writer_close_client(). If there is something to 38 * read, it calls sp_writer_recv(). 39 * 40 * The writer allocates a block containing a free buffer with 41 * sp_writer_alloc_block(), then writes something in the buffer 42 * (retrieved with sp_writer_block_get_buf(), then calls 43 * sp_writer_send_buf() to send the buffer or a subsection to the 44 * other side. When it is done with the block, it calls 45 * sp_writer_free_block(). If alloc fails, then the server must wait 46 * for events on the client fd (the ones where sp_writer_recv() is 47 * called), and then try to re-alloc. 48 * 49 * The reader (client) connect to the writer with sp_client_open() And 50 * select()s on the fd from sp_get_fd() until there is something to 51 * read. Then they must read using sp_client_recv() which will return 52 * the size of the buffer (positive) if there is a valid buffer (which 53 * is read only). It will return 0 if it is an internal message and a 54 * negative number if there was an error. If there was an error, the 55 * application must close the pipe with sp_close() and assume that all 56 * buffers are no longer valid. If was valid buffer was received, the 57 * client must release it with sp_client_recv_finish() when it is done 58 * reading from it. 59 */ 60 61 62 #ifndef __SHMPIPE_H__ 63 #define __SHMPIPE_H__ 64 65 #include <stdlib.h> 66 #include <stdint.h> 67 #include <sys/types.h> 68 #include <sys/stat.h> 69 #include <fcntl.h> 70 71 72 #ifdef __cplusplus 73 extern "C" { 74 #endif 75 76 typedef struct _ShmClient ShmClient; 77 typedef struct _ShmPipe ShmPipe; 78 typedef struct _ShmBlock ShmBlock; 79 typedef struct _ShmBuffer ShmBuffer; 80 81 typedef void (*sp_buffer_free_callback) (void * tag, void * user_data); 82 83 ShmPipe *sp_writer_create (const char *path, size_t size, mode_t perms); 84 const char *sp_writer_get_path (ShmPipe *pipe); 85 void sp_writer_close (ShmPipe * self, sp_buffer_free_callback callback, 86 void * user_data); 87 void *sp_get_data (ShmPipe * self); 88 void sp_set_data (ShmPipe * self, void *data); 89 90 int sp_writer_setperms_shm (ShmPipe * self, mode_t perms); 91 int sp_writer_resize (ShmPipe * self, size_t size); 92 93 int sp_get_fd (ShmPipe * self); 94 const char *sp_get_shm_area_name (ShmPipe *self); 95 int sp_writer_get_client_fd (ShmClient * client); 96 97 ShmBlock *sp_writer_alloc_block (ShmPipe * self, size_t size); 98 void sp_writer_free_block (ShmBlock *block); 99 int sp_writer_send_buf (ShmPipe * self, char *buf, size_t size, void * tag); 100 char *sp_writer_block_get_buf (ShmBlock *block); 101 ShmPipe *sp_writer_block_get_pipe (ShmBlock *block); 102 size_t sp_writer_get_max_buf_size (ShmPipe * self); 103 104 ShmClient * sp_writer_accept_client (ShmPipe * self); 105 void sp_writer_close_client (ShmPipe *self, ShmClient * client, 106 sp_buffer_free_callback callback, void * user_data); 107 int sp_writer_recv (ShmPipe * self, ShmClient * client, void ** tag); 108 109 int sp_writer_pending_writes (ShmPipe * self); 110 111 ShmBuffer *sp_writer_get_pending_buffers (ShmPipe * self); 112 ShmBuffer *sp_writer_get_next_buffer (ShmBuffer * buffer); 113 void *sp_writer_buf_get_tag (ShmBuffer * buffer); 114 115 ShmPipe *sp_client_open (const char *path); 116 long int sp_client_recv (ShmPipe * self, char **buf); 117 int sp_client_recv_finish (ShmPipe * self, char *buf); 118 void sp_client_close (ShmPipe * self); 119 120 #ifdef __cplusplus 121 } 122 #endif 123 124 #endif /* __SHMPIPE_H__ */ 125