ppapi/api/pp_var.idl

   1 /* Copyright (c) 2012 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  * This file defines the API for handling the passing of data types between
   8  * your module and the page.
   9  */
  10
  11 /**
  12  * The <code>PP_VarType</code> is an enumeration of the different types that
  13  * can be contained within a <code>PP_Var</code> structure.
  14  */
  15 [assert_size(4)]
  16 enum PP_VarType {
  17   /**
  18    * An undefined value.
  19    */
  20   PP_VARTYPE_UNDEFINED = 0,
  21
  22   /**
  23    * A NULL value. This is similar to undefined, but JavaScript differentiates
  24    * the two so it is exposed here as well.
  25    */
  26   PP_VARTYPE_NULL = 1,
  27
  28   /**
  29    * A boolean value, use the <code>as_bool</code> member of the var.
  30    */
  31   PP_VARTYPE_BOOL = 2,
  32
  33   /**
  34    * A 32-bit integer value. Use the <code>as_int</code> member of the var.
  35    */
  36   PP_VARTYPE_INT32 = 3,
  37
  38   /**
  39    * A double-precision floating point value. Use the <code>as_double</code>
  40    * member of the var.
  41    */
  42   PP_VARTYPE_DOUBLE = 4,
  43
  44   /**
  45    * The Var represents a string. The <code>as_id</code> field is used to
  46    * identify the string, which may be created and retrieved from the
  47    * <code>PPB_Var</code> interface. These objects are reference counted, so
  48    * AddRef and Release must be used properly to avoid memory leaks.
  49    */
  50   PP_VARTYPE_STRING = 5,
  51
  52   /**
  53    * Represents a JavaScript object. This vartype is not currently usable
  54    * from modules, although it is used internally for some tasks. These objects
  55    * are reference counted, so AddRef and Release must be used properly to avoid
  56    * memory leaks.
  57    */
  58   PP_VARTYPE_OBJECT = 6,
  59
  60   /**
  61    * Represents an array of Vars. The <code>as_id</code> field is used to
  62    * identify the array, which may be created and manipulated from the
  63    * <code>PPB_VarArray</code> interface. These objects are reference counted,
  64    * so AddRef and Release must be used properly to avoid memory leaks.
  65    */
  66   PP_VARTYPE_ARRAY = 7,
  67
  68   /**
  69    * Represents a mapping from strings to Vars. The <code>as_id</code> field is
  70    * used to identify the dictionary, which may be created and manipulated from
  71    * the <code>PPB_VarDictionary</code> interface. These objects are reference
  72    * counted, so AddRef and Release must be used properly to avoid memory leaks.
  73    */
  74   PP_VARTYPE_DICTIONARY = 8,
  75
  76   /**
  77    * ArrayBuffer represents a JavaScript ArrayBuffer. This is the type which
  78    * represents Typed Arrays in JavaScript. Unlike JavaScript 'Array', it is
  79    * only meant to contain basic numeric types, and is always stored
  80    * contiguously. See PPB_VarArrayBuffer_Dev for functions special to
  81    * ArrayBuffer vars. These objects are reference counted, so AddRef and
  82    * Release must be used properly to avoid memory leaks.
  83    */
  84   PP_VARTYPE_ARRAY_BUFFER = 9,
  85
  86   /**
  87    * Resources are not currently supported but will be added in the future
  88    * These objects are reference counted, so AddRef and Release must be used
  89    * properly to avoid memory leaks.
  90    */
  91   PP_VARTYPE_RESOURCE = 10
  92 };
  93
  94
  95 /**
  96  * The PP_VarValue union stores the data for any one of the types listed
  97  * in the PP_VarType enum.
  98  */
  99 [union] struct PP_VarValue {
 100   /**
 101    * If <code>type</code> is <code>PP_VARTYPE_BOOL</code>,
 102    * <code>as_bool</code> represents the value of this <code>PP_Var</code> as
 103    * <code>PP_Bool</code>.
 104    */
 105   PP_Bool as_bool;
 106
 107   /**
 108    * If <code>type</code> is <code>PP_VARTYPE_INT32</code>,
 109    * <code>as_int</code> represents the value of this <code>PP_Var</code> as
 110    * <code>int32_t</code>.
 111    */
 112   int32_t as_int;
 113
 114   /**
 115    * If <code>type</code> is <code>PP_VARTYPE_DOUBLE</code>,
 116    * <code>as_double</code> represents the value of this <code>PP_Var</code>
 117    * as <code>double</code>.
 118    */
 119   double_t as_double;
 120
 121   /**
 122    * If <code>type</code> is <code>PP_VARTYPE_STRING</code>,
 123    * <code>PP_VARTYPE_OBJECT</code>, <code>PP_VARTYPE_ARRAY</code>,
 124    * <code>PP_VARTYPE_DICTIONARY</code>, <code>PP_VARTYPE_ARRAY_BUFFER</code>,
 125    * or <code>PP_VARTYPE_RESOURCE</code>, <code>as_id</code> represents the
 126    * value of this <code>PP_Var</code> as an opaque handle assigned by the
 127    * browser. This handle is guaranteed never to be 0, so a module can
 128    * initialize this ID to 0 to indicate a "NULL handle."
 129    */
 130   int64_t as_id;
 131 };
 132
 133 /**
 134  * The <code>PP_VAR</code> struct is a variant data type and can contain any
 135  * value of one of the types named in the <code>PP_VarType</code> enum. This
 136  * structure is for passing data between native code which can be strongly
 137  * typed and the browser (JavaScript) which isn't strongly typed.
 138  *
 139  * JavaScript has a "number" type for holding a number, and does not
 140  * differentiate between floating point and integer numbers. The
 141  * JavaScript operations will try to optimize operations by using
 142  * integers when possible, but could end up with doubles. Therefore,
 143  * you can't assume a numeric <code>PP_Var</code> will be the type you expect.
 144  * Your code should be capable of handling either int32_t or double for numeric
 145  * PP_Vars sent from JavaScript.
 146  */
 147 [passByValue, returnByValue, assert_size(16)]
 148 struct PP_Var {
 149   PP_VarType type;
 150
 151   /**
 152    * The <code>padding</code> ensures <code>value</code> is aligned on an
 153    * 8-byte boundary relative to the start of the struct. Some compilers
 154    * align doubles on 8-byte boundaries for 32-bit x86, and some align on
 155    * 4-byte boundaries.
 156    */
 157   int32_t padding;
 158
 159   /**
 160    * This <code>value</code> represents the contents of the PP_Var. Only one of
 161    * the fields of <code>value</code> is valid at a time based upon
 162    * <code>type</code>.
 163    */
 164   PP_VarValue value;
 165 };
 166
 167
 168 #inline c
 169 /**
 170  * @addtogroup Functions
 171  * @{
 172  */
 173
 174 /**
 175  * PP_MakeUndefined() is used to wrap an undefined value into a
 176  * <code>PP_Var</code> struct for passing to the browser.
 177  *
 178  * @return A <code>PP_Var</code> structure.
 179  */
 180 PP_INLINE struct PP_Var PP_MakeUndefined(void) {
 181   struct PP_Var result = { PP_VARTYPE_UNDEFINED, 0, {PP_FALSE} };
 182   return result;
 183 }
 184
 185 /**
 186  * PP_MakeNull() is used to wrap a null value into a
 187  * <code>PP_Var</code> struct for passing to the browser.
 188  *
 189  * @return A <code>PP_Var</code> structure,
 190  */
 191 PP_INLINE struct PP_Var PP_MakeNull(void) {
 192   struct PP_Var result = { PP_VARTYPE_NULL, 0, {PP_FALSE} };
 193   return result;
 194 }
 195
 196 /**
 197  * PP_MakeBool() is used to wrap a boolean value into a
 198  * <code>PP_Var</code> struct for passing to the browser.
 199  *
 200  * @param[in] value A <code>PP_Bool</code> enumeration to
 201  * wrap.
 202  *
 203  * @return A <code>PP_Var</code> structure.
 204  */
 205 PP_INLINE struct PP_Var PP_MakeBool(PP_Bool value) {
 206   struct PP_Var result = { PP_VARTYPE_BOOL, 0, {PP_FALSE} };
 207   result.value.as_bool = value;
 208   return result;
 209 }
 210
 211 /**
 212  * PP_MakeInt32() is used to wrap a 32 bit integer value
 213  * into a <code>PP_Var</code> struct for passing to the browser.
 214  *
 215  * @param[in] value An int32 to wrap.
 216  *
 217  * @return A <code>PP_Var</code> structure.
 218  */
 219 PP_INLINE struct PP_Var PP_MakeInt32(int32_t value) {
 220   struct PP_Var result = { PP_VARTYPE_INT32, 0, {PP_FALSE} };
 221   result.value.as_int = value;
 222   return result;
 223 }
 224
 225 /**
 226  * PP_MakeDouble() is used to wrap a double value into a
 227  * <code>PP_Var</code> struct for passing to the browser.
 228  *
 229  * @param[in] value A double to wrap.
 230  *
 231  * @return A <code>PP_Var</code> structure.
 232  */
 233 PP_INLINE struct PP_Var PP_MakeDouble(double value) {
 234   struct PP_Var result = { PP_VARTYPE_DOUBLE, 0, {PP_FALSE} };
 235   result.value.as_double = value;
 236   return result;
 237 }
 238 /**
 239  * @}
 240  */
 241
 242 #endinl
 243