ppapi/c/ppb_file_mapping.h

   1 /* Copyright 2014 The Chromium Authors. All rights reserved.
   2  * Use of this source code is governed by a BSD-style license that can be
   3  * found in the LICENSE file.
   4  */
   5
   6 /* From ppb_file_mapping.idl modified Mon Jan 27 11:00:43 2014. */
   7
   8 #ifndef PPAPI_C_PPB_FILE_MAPPING_H_
   9 #define PPAPI_C_PPB_FILE_MAPPING_H_
  10
  11 #include "ppapi/c/pp_completion_callback.h"
  12 #include "ppapi/c/pp_instance.h"
  13 #include "ppapi/c/pp_macros.h"
  14 #include "ppapi/c/pp_resource.h"
  15 #include "ppapi/c/pp_stdint.h"
  16
  17 #define PPB_FILEMAPPING_INTERFACE_0_1 "PPB_FileMapping;0.1" /* dev */
  18 /**
  19  * @file
  20  * This file defines methods for mapping and unmapping files into and out of
  21  * memory.
  22  */
  23
  24
  25 /**
  26  * @addtogroup Enums
  27  * @{
  28  */
  29 /**
  30  * The PP_FileMapProtection values indicate the permissions requested for the
  31  * file mapping. These should be used in a uint32_t bitfield.
  32  */
  33 typedef enum {
  34   /** Requests read access to the mapped address. */
  35   PP_FILEMAPPROTECTION_READ = 1u << 0,
  36   /** Requests write access to the mapped address. */
  37   PP_FILEMAPPROTECTION_WRITE = 1u << 1
  38 } PP_FileMapProtection;
  39 PP_COMPILE_ASSERT_SIZE_IN_BYTES(PP_FileMapProtection, 4);
  40
  41 /**
  42  * The PP_FileMapFlags contain flag values for use with Map().
  43  */
  44 typedef enum {
  45   /**
  46    * Requests a shared mapping. If this flag is set, changes written to the
  47    * memory region will be reflected in the underlying file and will thus
  48    * eventually be visible to other processes which have opened the file. The
  49    * file may not actually be updated until Unmap() is called. This is only
  50    * valid if the PPB_FileIO resource was opened with write permission.
  51    */
  52   PP_FILEMAPFLAG_SHARED = 1u << 0,
  53   /**
  54    * Requests a copy-on-write mapping. If this flag is set, changes are not
  55    * written to the underlying file, but only in the memory of the process
  56    * (copy-on-write).
  57    */
  58   PP_FILEMAPFLAG_PRIVATE = 1u << 1,
  59   /**
  60    * Forces Map() to map the file contents at the provided |address|. If Map()
  61    * can not comply, Map() will fail.
  62    */
  63   PP_FILEMAPFLAG_FIXED = 1u << 2
  64 } PP_FileMapFlags;
  65 PP_COMPILE_ASSERT_SIZE_IN_BYTES(PP_FileMapFlags, 4);
  66 /**
  67  * @}
  68  */
  69
  70 /**
  71  * @addtogroup Interfaces
  72  * @{
  73  */
  74 /**
  75  *  PPB_FileMapping contains functions for mapping and unmapping files into and
  76  *  out of memory.
  77  */
  78 struct PPB_FileMapping_0_1 { /* dev */
  79   /**
  80    * Map() maps the contents from an offset of the file into memory.
  81    *
  82    * @param[in] instance A <code>PP_Instance</code> identifying one instance of
  83    * a module.
  84    * @param[in] file_io A <code>PPB_FileIO</code> <code>PP_Resource</code>
  85    * corresponding to the file that should be mapped in to memory.
  86    * @param[in] length The number of bytes to map.
  87    * @param[in] map_protection A bitfield containing values from
  88    * <code>PP_FileMapProtection</code>, indicating what memory operations
  89    * should be permitted on the mapped region.
  90    * @param[in] map_flags A bitfield containing values from
  91    * <code>PP_FileMapFlags</code>, providing options for the behavior of Map.
  92    * If the region is to be writeable, then exactly one of
  93    * <code>PP_FILEMAPFLAG_SHARED</code> or <code>PP_FILEMAPFLAG_PRIVATE</code>
  94    * must be set.
  95    * @param[in] offset The offset into the file. Must be a multiple of the
  96    * Map page size as returned by GetMapPageSize().
  97    * @param[inout] address The value of <code>*address</code>, if non-NULL,
  98    * will be used as a hint to determine where in memory the file should be
  99    * mapped. If the value is NULL, the host operating system will choose
 100    * <code>address</code>. Upon Map() completing, <code>*address</code> will
 101    * contain the actual memory location at which the file was mapped. If the
 102    * plugin provides a non-NULL <code>*address</code>, it must be a multiple of
 103    * the map page size as returned by GetMapPageSize().
 104    * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
 105    * completion of Map().
 106    *
 107    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
 108    */
 109   int32_t (*Map)(PP_Instance instance,
 110                  PP_Resource file_io,
 111                  int64_t length,
 112                  uint32_t map_protection,
 113                  uint32_t map_flags,
 114                  int64_t offset,
 115                  void** address,
 116                  struct PP_CompletionCallback callback);
 117   /**
 118    * Unmap() deletes the mapping of the specified address.  The specified
 119    * address must have been retrieved with Map().
 120    * @param[in] instance A <code>PP_Instance</code> identifying the instance.
 121    * @param[in] address The starting address of the address in memory to
 122    * be unmapped.
 123    * @param[in] length The length of the region to unmap.
 124    * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
 125    * completion of Unmap().
 126    *
 127    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
 128    */
 129   int32_t (*Unmap)(PP_Instance instance,
 130                    const void* address,
 131                    int64_t length,
 132                    struct PP_CompletionCallback callback);
 133   /**
 134    * GetMapPageSize() retrieves the size of pages that Map() uses.
 135    *
 136    * @param[in] instance A <code>PP_Instance</code> identifying the instance.
 137    *
 138    * @return The size of pages that Map() uses. Returns 0 on failure.
 139    */
 140   int64_t (*GetMapPageSize)(PP_Instance instance);
 141 };
 142 /**
 143  * @}
 144  */
 145
 146 #endif  /* PPAPI_C_PPB_FILE_MAPPING_H_ */
 147