ppapi/api/ppb_file_mapping.idl

   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
   7 /**
   8  * This file defines methods for mapping and unmapping files into and out of
   9  * memory.
  10  */
  11
  12 [generate_thunk]
  13
  14 label Chrome {
  15   [channel=dev] M34 = 0.1
  16 };
  17
  18 /**
  19  * The PP_FileMapProtection values indicate the permissions requested for the
  20  * file mapping. These should be used in a uint32_t bitfield.
  21  */
  22 [assert_size(4)]
  23 enum PP_FileMapProtection {
  24   /** Requests read access to the mapped address. */
  25   PP_FILEMAPPROTECTION_READ = 1u << 0,
  26
  27   /** Requests write access to the mapped address. */
  28   PP_FILEMAPPROTECTION_WRITE = 1u << 1
  29 };
  30
  31 /**
  32  * The PP_FileMapFlags contain flag values for use with Map().
  33  */
  34 [assert_size(4)]
  35 enum PP_FileMapFlags {
  36   /**
  37    * Requests a shared mapping. If this flag is set, changes written to the
  38    * memory region will be reflected in the underlying file and will thus
  39    * eventually be visible to other processes which have opened the file. The
  40    * file may not actually be updated until Unmap() is called. This is only
  41    * valid if the PPB_FileIO resource was opened with write permission.
  42    */
  43   PP_FILEMAPFLAG_SHARED = 1u << 0,
  44
  45   /**
  46    * Requests a copy-on-write mapping. If this flag is set, changes are not
  47    * written to the underlying file, but only in the memory of the process
  48    * (copy-on-write).
  49    */
  50   PP_FILEMAPFLAG_PRIVATE = 1u << 1,
  51
  52   /**
  53    * Forces Map() to map the file contents at the provided |address|. If Map()
  54    * can not comply, Map() will fail.
  55    */
  56   PP_FILEMAPFLAG_FIXED = 1u << 2
  57 };
  58
  59 /**
  60  *  PPB_FileMapping contains functions for mapping and unmapping files into and
  61  *  out of memory.
  62  */
  63 [singleton]
  64 interface PPB_FileMapping {
  65   /**
  66    * Map() maps the contents from an offset of the file into memory.
  67    *
  68    * @param[in] instance A <code>PP_Instance</code> identifying one instance of
  69    * a module.
  70    * @param[in] file_io A <code>PPB_FileIO</code> <code>PP_Resource</code>
  71    * corresponding to the file that should be mapped in to memory.
  72    * @param[in] length The number of bytes to map.
  73    * @param[in] map_protection A bitfield containing values from
  74    * <code>PP_FileMapProtection</code>, indicating what memory operations
  75    * should be permitted on the mapped region.
  76    * @param[in] map_flags A bitfield containing values from
  77    * <code>PP_FileMapFlags</code>, providing options for the behavior of Map.
  78    * If the region is to be writeable, then exactly one of
  79    * <code>PP_FILEMAPFLAG_SHARED</code> or <code>PP_FILEMAPFLAG_PRIVATE</code>
  80    * must be set.
  81    * @param[in] offset The offset into the file. Must be a multiple of the
  82    * Map page size as returned by GetMapPageSize().
  83    * @param[inout] address The value of <code>*address</code>, if non-NULL,
  84    * will be used as a hint to determine where in memory the file should be
  85    * mapped. If the value is NULL, the host operating system will choose
  86    * <code>address</code>. Upon Map() completing, <code>*address</code> will
  87    * contain the actual memory location at which the file was mapped. If the
  88    * plugin provides a non-NULL <code>*address</code>, it must be a multiple of
  89    * the map page size as returned by GetMapPageSize().
  90    * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
  91    * completion of Map().
  92    *
  93    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
  94    */
  95   int32_t Map([in] PP_Instance instance,
  96               [in] PP_Resource file_io,
  97               [in] int64_t length,
  98               [in] uint32_t map_protection,
  99               [in] uint32_t map_flags,
 100               [in] int64_t offset,
 101               [inout] mem_ptr_t address,
 102               [in] PP_CompletionCallback callback);
 103
 104   /**
 105    * Unmap() deletes the mapping of the specified address.  The specified
 106    * address must have been retrieved with Map().
 107    * @param[in] instance A <code>PP_Instance</code> identifying the instance.
 108    * @param[in] address The starting address of the address in memory to
 109    * be unmapped.
 110    * @param[in] length The length of the region to unmap.
 111    * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
 112    * completion of Unmap().
 113    *
 114    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
 115    */
 116   int32_t Unmap([in] PP_Instance instance,
 117                 [in] mem_t address,
 118                 [in] int64_t length,
 119                 [in] PP_CompletionCallback callback);
 120
 121   /**
 122    * GetMapPageSize() retrieves the size of pages that Map() uses.
 123    *
 124    * @param[in] instance A <code>PP_Instance</code> identifying the instance.
 125    *
 126    * @return The size of pages that Map() uses. Returns 0 on failure.
 127    */
 128   [on_failure=0]
 129   int64_t GetMapPageSize(PP_Instance instance);
 130 };
 131