ppapi/c/pp_var.h

   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 /* From pp_var.idl modified Thu Sep 12 16:41:36 2013. */
   7
   8 #ifndef PPAPI_C_PP_VAR_H_
   9 #define PPAPI_C_PP_VAR_H_
  10
  11 #include "ppapi/c/pp_bool.h"
  12 #include "ppapi/c/pp_macros.h"
  13 #include "ppapi/c/pp_stdint.h"
  14
  15 /**
  16  * @file
  17  * This file defines the API for handling the passing of data types between
  18  * your module and the page.
  19  */
  20
  21
  22 /**
  23  * @addtogroup Enums
  24  * @{
  25  */
  26 /**
  27  * The <code>PP_VarType</code> is an enumeration of the different types that
  28  * can be contained within a <code>PP_Var</code> structure.
  29  */
  30 typedef enum {
  31   /**
  32    * An undefined value.
  33    */
  34   PP_VARTYPE_UNDEFINED = 0,
  35   /**
  36    * A NULL value. This is similar to undefined, but JavaScript differentiates
  37    * the two so it is exposed here as well.
  38    */
  39   PP_VARTYPE_NULL = 1,
  40   /**
  41    * A boolean value, use the <code>as_bool</code> member of the var.
  42    */
  43   PP_VARTYPE_BOOL = 2,
  44   /**
  45    * A 32-bit integer value. Use the <code>as_int</code> member of the var.
  46    */
  47   PP_VARTYPE_INT32 = 3,
  48   /**
  49    * A double-precision floating point value. Use the <code>as_double</code>
  50    * member of the var.
  51    */
  52   PP_VARTYPE_DOUBLE = 4,
  53   /**
  54    * The Var represents a string. The <code>as_id</code> field is used to
  55    * identify the string, which may be created and retrieved from the
  56    * <code>PPB_Var</code> interface. These objects are reference counted, so
  57    * AddRef and Release must be used properly to avoid memory leaks.
  58    */
  59   PP_VARTYPE_STRING = 5,
  60   /**
  61    * Represents a JavaScript object. This vartype is not currently usable
  62    * from modules, although it is used internally for some tasks. These objects
  63    * are reference counted, so AddRef and Release must be used properly to avoid
  64    * memory leaks.
  65    */
  66   PP_VARTYPE_OBJECT = 6,
  67   /**
  68    * Represents an array of Vars. The <code>as_id</code> field is used to
  69    * identify the array, which may be created and manipulated from the
  70    * <code>PPB_VarArray</code> interface. These objects are reference counted,
  71    * so AddRef and Release must be used properly to avoid memory leaks.
  72    */
  73   PP_VARTYPE_ARRAY = 7,
  74   /**
  75    * Represents a mapping from strings to Vars. The <code>as_id</code> field is
  76    * used to identify the dictionary, which may be created and manipulated from
  77    * the <code>PPB_VarDictionary</code> interface. These objects are reference
  78    * counted, so AddRef and Release must be used properly to avoid memory leaks.
  79    */
  80   PP_VARTYPE_DICTIONARY = 8,
  81   /**
  82    * ArrayBuffer represents a JavaScript ArrayBuffer. This is the type which
  83    * represents Typed Arrays in JavaScript. Unlike JavaScript 'Array', it is
  84    * only meant to contain basic numeric types, and is always stored
  85    * contiguously. See PPB_VarArrayBuffer_Dev for functions special to
  86    * ArrayBuffer vars. These objects are reference counted, so AddRef and
  87    * Release must be used properly to avoid memory leaks.
  88    */
  89   PP_VARTYPE_ARRAY_BUFFER = 9,
  90   /**
  91    * Resources are not currently supported but will be added in the future
  92    * These objects are reference counted, so AddRef and Release must be used
  93    * properly to avoid memory leaks.
  94    */
  95   PP_VARTYPE_RESOURCE = 10
  96 } PP_VarType;
  97 PP_COMPILE_ASSERT_SIZE_IN_BYTES(PP_VarType, 4);
  98 /**
  99  * @}
 100  */
 101
 102 /**
 103  * @addtogroup Structs
 104  * @{
 105  */
 106 /**
 107  * The PP_VarValue union stores the data for any one of the types listed
 108  * in the PP_VarType enum.
 109  */
 110 union PP_VarValue {
 111   /**
 112    * If <code>type</code> is <code>PP_VARTYPE_BOOL</code>,
 113    * <code>as_bool</code> represents the value of this <code>PP_Var</code> as
 114    * <code>PP_Bool</code>.
 115    */
 116   PP_Bool as_bool;
 117   /**
 118    * If <code>type</code> is <code>PP_VARTYPE_INT32</code>,
 119    * <code>as_int</code> represents the value of this <code>PP_Var</code> as
 120    * <code>int32_t</code>.
 121    */
 122   int32_t as_int;
 123   /**
 124    * If <code>type</code> is <code>PP_VARTYPE_DOUBLE</code>,
 125    * <code>as_double</code> represents the value of this <code>PP_Var</code>
 126    * as <code>double</code>.
 127    */
 128   double as_double;
 129   /**
 130    * If <code>type</code> is <code>PP_VARTYPE_STRING</code>,
 131    * <code>PP_VARTYPE_OBJECT</code>, <code>PP_VARTYPE_ARRAY</code>,
 132    * <code>PP_VARTYPE_DICTIONARY</code>, <code>PP_VARTYPE_ARRAY_BUFFER</code>,
 133    * or <code>PP_VARTYPE_RESOURCE</code>, <code>as_id</code> represents the
 134    * value of this <code>PP_Var</code> as an opaque handle assigned by the
 135    * browser. This handle is guaranteed never to be 0, so a module can
 136    * initialize this ID to 0 to indicate a "NULL handle."
 137    */
 138   int64_t as_id;
 139 };
 140
 141 /**
 142  * The <code>PP_VAR</code> struct is a variant data type and can contain any
 143  * value of one of the types named in the <code>PP_VarType</code> enum. This
 144  * structure is for passing data between native code which can be strongly
 145  * typed and the browser (JavaScript) which isn't strongly typed.
 146  *
 147  * JavaScript has a "number" type for holding a number, and does not
 148  * differentiate between floating point and integer numbers. The
 149  * JavaScript operations will try to optimize operations by using
 150  * integers when possible, but could end up with doubles. Therefore,
 151  * you can't assume a numeric <code>PP_Var</code> will be the type you expect.
 152  * Your code should be capable of handling either int32_t or double for numeric
 153  * PP_Vars sent from JavaScript.
 154  */
 155 struct PP_Var {
 156   PP_VarType type;
 157   /**
 158    * The <code>padding</code> ensures <code>value</code> is aligned on an
 159    * 8-byte boundary relative to the start of the struct. Some compilers
 160    * align doubles on 8-byte boundaries for 32-bit x86, and some align on
 161    * 4-byte boundaries.
 162    */
 163   int32_t padding;
 164   /**
 165    * This <code>value</code> represents the contents of the PP_Var. Only one of
 166    * the fields of <code>value</code> is valid at a time based upon
 167    * <code>type</code>.
 168    */
 169   union PP_VarValue value;
 170 };
 171 PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_Var, 16);
 172 /**
 173  * @}
 174  */
 175
 176 /**
 177  * @addtogroup Functions
 178  * @{
 179  */
 180
 181 /**
 182  * PP_MakeUndefined() is used to wrap an undefined value into a
 183  * <code>PP_Var</code> struct for passing to the browser.
 184  *
 185  * @return A <code>PP_Var</code> structure.
 186  */
 187 PP_INLINE struct PP_Var PP_MakeUndefined(void) {
 188   struct PP_Var result = { PP_VARTYPE_UNDEFINED, 0, {PP_FALSE} };
 189   return result;
 190 }
 191
 192 /**
 193  * PP_MakeNull() is used to wrap a null value into a
 194  * <code>PP_Var</code> struct for passing to the browser.
 195  *
 196  * @return A <code>PP_Var</code> structure,
 197  */
 198 PP_INLINE struct PP_Var PP_MakeNull(void) {
 199   struct PP_Var result = { PP_VARTYPE_NULL, 0, {PP_FALSE} };
 200   return result;
 201 }
 202
 203 /**
 204  * PP_MakeBool() is used to wrap a boolean value into a
 205  * <code>PP_Var</code> struct for passing to the browser.
 206  *
 207  * @param[in] value A <code>PP_Bool</code> enumeration to
 208  * wrap.
 209  *
 210  * @return A <code>PP_Var</code> structure.
 211  */
 212 PP_INLINE struct PP_Var PP_MakeBool(PP_Bool value) {
 213   struct PP_Var result = { PP_VARTYPE_BOOL, 0, {PP_FALSE} };
 214   result.value.as_bool = value;
 215   return result;
 216 }
 217
 218 /**
 219  * PP_MakeInt32() is used to wrap a 32 bit integer value
 220  * into a <code>PP_Var</code> struct for passing to the browser.
 221  *
 222  * @param[in] value An int32 to wrap.
 223  *
 224  * @return A <code>PP_Var</code> structure.
 225  */
 226 PP_INLINE struct PP_Var PP_MakeInt32(int32_t value) {
 227   struct PP_Var result = { PP_VARTYPE_INT32, 0, {PP_FALSE} };
 228   result.value.as_int = value;
 229   return result;
 230 }
 231
 232 /**
 233  * PP_MakeDouble() is used to wrap a double value into a
 234  * <code>PP_Var</code> struct for passing to the browser.
 235  *
 236  * @param[in] value A double to wrap.
 237  *
 238  * @return A <code>PP_Var</code> structure.
 239  */
 240 PP_INLINE struct PP_Var PP_MakeDouble(double value) {
 241   struct PP_Var result = { PP_VARTYPE_DOUBLE, 0, {PP_FALSE} };
 242   result.value.as_double = value;
 243   return result;
 244 }
 245 /**
 246  * @}
 247  */
 248
 249 #endif  /* PPAPI_C_PP_VAR_H_ */
 250