libraries/source/spidermonkey/include-win32-release/js/Array.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /* Array-related operations. */
   7
   8 #ifndef js_Array_h
   9 #define js_Array_h
  10
  11 #include <stddef.h>  // size_t
  12 #include <stdint.h>  // uint32_t
  13
  14 #include "jstypes.h"  // JS_PUBLIC_API
  15
  16 #include "js/TypeDecls.h"
  17
  18 namespace JS {
  19
  20 class HandleValueArray;
  21
  22 /**
  23  * Create an Array from the current realm with the given contents.
  24  */
  25 extern JS_PUBLIC_API JSObject* NewArrayObject(JSContext* cx,
  26                                               const HandleValueArray& contents);
  27
  28 /**
  29  * Create an Array from the current realm with the given length and allocate
  30  * memory for all its elements.  (The elements nonetheless will not exist as
  31  * properties on the returned array until values have been assigned to them.)
  32  */
  33 extern JS_PUBLIC_API JSObject* NewArrayObject(JSContext* cx, size_t length);
  34
  35 /**
  36  * Determine whether |value| is an Array object or a wrapper around one.  (An
  37  * ES6 proxy whose target is an Array object, e.g.
  38  * |var target = [], handler = {}; Proxy.revocable(target, handler).proxy|, is
  39  * not considered to be an Array.)
  40  *
  41  * On success set |*isArray| accordingly and return true; on failure return
  42  * false.
  43  */
  44 extern JS_PUBLIC_API bool IsArrayObject(JSContext* cx, Handle<Value> value,
  45                                         bool* isArray);
  46
  47 /**
  48  * Determine whether |obj| is an Array object or a wrapper around one.  (An
  49  * ES6 proxy whose target is an Array object, e.g.
  50  * |var target = [], handler = {}; Proxy.revocable(target, handler).proxy|, is
  51  * not considered to be an Array.)
  52  *
  53  * On success set |*isArray| accordingly and return true; on failure return
  54  * false.
  55  */
  56 extern JS_PUBLIC_API bool IsArrayObject(JSContext* cx, Handle<JSObject*> obj,
  57                                         bool* isArray);
  58
  59 /**
  60  * Store |*lengthp = ToLength(obj.length)| and return true on success, else
  61  * return false.
  62  *
  63  * If the length does not fit in |uint32_t|, an exception is reported and false
  64  * is returned.
  65  *
  66  * |ToLength| converts its input to an integer usable to index an
  67  * array-like object.
  68  *
  69  * If |obj| is an Array, this overall operation is the same as getting
  70  * |obj.length|.
  71  */
  72 extern JS_PUBLIC_API bool GetArrayLength(JSContext* cx, Handle<JSObject*> obj,
  73                                          uint32_t* lengthp);
  74
  75 /**
  76  * Perform |obj.length = length| as if in strict mode code, with a fast path for
  77  * the case where |obj| is an Array.
  78  *
  79  * This operation is exactly and only assigning to a "length" property.  In
  80  * general, it can invoke an existing "length" setter, throw if the property is
  81  * non-writable, or do anything else a property-set operation might do.
  82  */
  83 extern JS_PUBLIC_API bool SetArrayLength(JSContext* cx, Handle<JSObject*> obj,
  84                                          uint32_t length);
  85
  86 /**
  87  * The answer to a successful query as to whether an object is an Array per
  88  * ES6's internal |IsArray| operation (as exposed by |Array.isArray|).
  89  */
  90 enum class IsArrayAnswer { Array, NotArray, RevokedProxy };
  91
  92 /**
  93  * ES6 7.2.2.
  94  *
  95  * Returns false on failure, otherwise returns true and sets |*isArray|
  96  * indicating whether the object passes ECMAScript's IsArray test.  This is the
  97  * same test performed by |Array.isArray|.
  98  *
  99  * This is NOT the same as asking whether |obj| is an Array or a wrapper around
 100  * one.  If |obj| is a proxy created by |Proxy.revocable()| and has been
 101  * revoked, or if |obj| is a proxy whose target (at any number of hops) is a
 102  * revoked proxy, this method throws a TypeError and returns false.
 103  */
 104 extern JS_PUBLIC_API bool IsArray(JSContext* cx, Handle<JSObject*> obj,
 105                                   bool* isArray);
 106
 107 /**
 108  * Identical to IsArray above, but the nature of the object (if successfully
 109  * determined) is communicated via |*answer|.  In particular this method
 110  * returns true and sets |*answer = IsArrayAnswer::RevokedProxy| when called on
 111  * a revoked proxy.
 112  *
 113  * Most users will want the overload above, not this one.
 114  */
 115 extern JS_PUBLIC_API bool IsArray(JSContext* cx, Handle<JSObject*> obj,
 116                                   IsArrayAnswer* answer);
 117
 118 }  // namespace JS
 119
 120 #endif  // js_Array_h