/platform/external/webkit/WebCore/bindings/v8/npruntime_priv.h

 1/*
 2 * Copyright (C) 2003, 2006 Apple Computer, Inc.  All rights reserved.
 3 *
 4 * Redistribution and use in source and binary forms, with or without
 5 * modification, are permitted provided that the following conditions
 6 * are met:
 7 * 1. Redistributions of source code must retain the above copyright
 8 *    notice, this list of conditions and the following disclaimer.
 9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef npruntime_priv_h
27#define npruntime_priv_h
28
29#if PLATFORM(CHROMIUM)
30#include <bindings/npruntime.h>
31#else
32#include "npruntime.h"
33#endif
34
35#ifdef __cplusplus
36extern "C" {
37#endif
38
39/*
40    _NPN_InitializeVariantWithStringCopy() will copy string data.  The string data
41    will be deallocated by calls to NPReleaseVariantValue().
42*/
43void _NPN_InitializeVariantWithStringCopy(NPVariant*, const NPString*);
44void _NPN_DeallocateObject(NPObject*);
45
46// The following routines allow the browser to aggressively cleanup NPObjects
47// on a per plugin basis.  All NPObjects used through the NPRuntime API should
48// be "registered" while they are alive.  After an object has been
49// deleted, it is possible for Javascript to have a reference to that object
50// which has not yet been garbage collected.  Javascript access to NPObjects
51// will reference this registry to determine if the object is accessible or
52// not.
53
54// Windows introduces an additional complication for objects created by the
55// plugin.  Plugins load inside of a DLL.  Each DLL has it's own heap.  If
56// the browser unloads the plugin DLL, all objects created within the DLL's
57// heap instantly become invalid.  Normally, when WebKit drops the reference
58// on the top-level plugin object, it tells the plugin manager that the
59// plugin can be destroyed, which can unload the DLL.  So, we must eliminate
60// all pointers to any object ever created by the plugin.
61
62// We generally associate NPObjects with an owner.  The owner of an NPObject
63// is an NPObject which, when destroyed, also destroys all objects it owns.
64// For example, if an NPAPI plugin creates 10 sub-NPObjects, all 11 objects
65// (the NPAPI plugin + its 10 sub-objects) should become inaccessible
66// simultaneously.
67
68// The ownership hierarchy is flat, and not a tree.  Imagine the following
69// object creation:
70//     PluginObject
71//          |
72//          +-- Creates -----> Object1
73//                                |
74//                                +-- Creates -----> Object2
75//
76// PluginObject will be the "owner" for both Object1 and Object2.
77
78// Register an NPObject with the runtime.  If the owner is NULL, the
79// object is treated as an owning object.  If owner is not NULL,
80// this object will be registered as owned by owner's top-level owner.
81void _NPN_RegisterObject(NPObject*, NPObject* owner);
82
83// Unregister an NPObject with the runtime.  If obj is an owning
84// object, this call will also unregister all of the owned objects.
85void _NPN_UnregisterObject(NPObject*);
86
87// Check to see if an object is registered with the runtime.
88// Return true if registered, false otherwise.
89bool _NPN_IsAlive(NPObject*);
90
91#ifdef __cplusplus
92}  /* end extern "C" */
93#endif
94
95#endif // npruntime_priv_h