npruntime.h

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/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * Copyright (c) 2004, Apple Computer, Inc. and The Mozilla Foundation.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 3. Neither the names of Apple Computer, Inc. ("Apple") or The Mozilla
 * Foundation ("Mozilla") nor the names of their contributors may be used
 * to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE, MOZILLA AND THEIR CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE, MOZILLA OR
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 */
#ifndef _NP_RUNTIME_H_
#define _NP_RUNTIME_H_

#ifdef __cplusplus
extern "C" {
#endif

#include "nptypes.h"

/*
    This API is used to facilitate binding code written in C to script
    objects.  The API in this header does not assume the presence of a
    user agent.  That is, it can be used to bind C code to scripting
    environments outside of the context of a user agent.

    However, the normal use of the this API is in the context of a
    scripting environment running in a browser or other user agent.
    In particular it is used to support the extended Netscape
    script-ability API for plugins (NP-SAP).  NP-SAP is an extension
    of the Netscape plugin API.  As such we have adopted the use of
    the "NP" prefix for this API.

    The following NP{N|P}Variables were added to the Netscape plugin
    API (in npapi.h):

    NPNVWindowNPObject
    NPNVPluginElementNPObject
    NPPVpluginScriptableNPObject

    These variables are exposed through NPN_GetValue() and
    NPP_GetValue() (respectively) and are used to establish the
    initial binding between the user agent and native code.  The DOM
    objects in the user agent can be examined and manipulated using
    the NPN_ functions that operate on NPObjects described in this
    header.

    To the extent possible the assumptions about the scripting
    language used by the scripting environment have been minimized.
*/

#define NP_BEGIN_MACRO  do {
#define NP_END_MACRO    } while (0)

/*
    Objects (non-primitive data) passed between 'C' and script is
    always wrapped in an NPObject.  The 'interface' of an NPObject is
    described by an NPClass.
*/
typedef struct NPObject NPObject;
typedef struct NPClass NPClass;

typedef char NPUTF8;
typedef struct _NPString {
    const NPUTF8 *UTF8Characters;
    uint32_t UTF8Length;
} NPString;

typedef enum {
    NPVariantType_Void,
    NPVariantType_Null,
    NPVariantType_Bool,
    NPVariantType_Int32,
    NPVariantType_Double,
    NPVariantType_String,
    NPVariantType_Object
} NPVariantType;

typedef struct _NPVariant {
    NPVariantType type;
    union {
        bool boolValue;
        int32_t intValue;
        double doubleValue;
        NPString stringValue;
        NPObject *objectValue;
    } value;
} NPVariant;

/*
    NPN_ReleaseVariantValue is called on all 'out' parameters
    references.  Specifically it is to be called on variants that own
    their value, as is the case with all non-const NPVariant*
    arguments after a successful call to any methods (except this one)
    in this API.

    After calling NPN_ReleaseVariantValue, the type of the variant
    will be NPVariantType_Void.
*/
void NPN_ReleaseVariantValue(NPVariant *variant);

#define NPVARIANT_IS_VOID(_v)    ((_v).type == NPVariantType_Void)
#define NPVARIANT_IS_NULL(_v)    ((_v).type == NPVariantType_Null)
#define NPVARIANT_IS_BOOLEAN(_v) ((_v).type == NPVariantType_Bool)
#define NPVARIANT_IS_INT32(_v)   ((_v).type == NPVariantType_Int32)
#define NPVARIANT_IS_DOUBLE(_v)  ((_v).type == NPVariantType_Double)
#define NPVARIANT_IS_STRING(_v)  ((_v).type == NPVariantType_String)
#define NPVARIANT_IS_OBJECT(_v)  ((_v).type == NPVariantType_Object)

#define NPVARIANT_TO_BOOLEAN(_v) ((_v).value.boolValue)
#define NPVARIANT_TO_INT32(_v)   ((_v).value.intValue)
#define NPVARIANT_TO_DOUBLE(_v)  ((_v).value.doubleValue)
#define NPVARIANT_TO_STRING(_v)  ((_v).value.stringValue)
#define NPVARIANT_TO_OBJECT(_v)  ((_v).value.objectValue)

#define VOID_TO_NPVARIANT(_v)                                                 \
NP_BEGIN_MACRO                                                                \
    (_v).type = NPVariantType_Void;                                           \
    (_v).value.objectValue = NULL;                                            \
NP_END_MACRO

#define NULL_TO_NPVARIANT(_v)                                                 \
NP_BEGIN_MACRO                                                                \
    (_v).type = NPVariantType_Null;                                           \
    (_v).value.objectValue = NULL;                                            \
NP_END_MACRO

#define BOOLEAN_TO_NPVARIANT(_val, _v)                                        \
NP_BEGIN_MACRO                                                                \
    (_v).type = NPVariantType_Bool;                                           \
    (_v).value.boolValue = !!(_val);                                          \
NP_END_MACRO

#define INT32_TO_NPVARIANT(_val, _v)                                          \
NP_BEGIN_MACRO                                                                \
    (_v).type = NPVariantType_Int32;                                          \
    (_v).value.intValue = _val;                                               \
NP_END_MACRO

#define DOUBLE_TO_NPVARIANT(_val, _v)                                         \
NP_BEGIN_MACRO                                                                \
    (_v).type = NPVariantType_Double;                                         \
    (_v).value.doubleValue = _val;                                            \
NP_END_MACRO

#define STRINGZ_TO_NPVARIANT(_val, _v)                                        \
NP_BEGIN_MACRO                                                                \
    (_v).type = NPVariantType_String;                                         \
    NPString str = { _val, (uint32_t)(strlen(_val)) };                        \
    (_v).value.stringValue = str;                                             \
NP_END_MACRO

#define STRINGN_TO_NPVARIANT(_val, _len, _v)                                  \
NP_BEGIN_MACRO                                                                \
    (_v).type = NPVariantType_String;                                         \
    NPString str = { _val, (uint32_t)(_len) };                                \
    (_v).value.stringValue = str;                                             \
NP_END_MACRO

#define OBJECT_TO_NPVARIANT(_val, _v)                                         \
NP_BEGIN_MACRO                                                                \
    (_v).type = NPVariantType_Object;                                         \
    (_v).value.objectValue = _val;                                            \
NP_END_MACRO


/*
  Type mappings (JavaScript types have been used for illustration
    purposes):

  JavaScript       to             C (NPVariant with type:)
  undefined                       NPVariantType_Void
  null                            NPVariantType_Null
  Boolean                         NPVariantType_Bool
  Number                          NPVariantType_Double or NPVariantType_Int32
  String                          NPVariantType_String
  Object                          NPVariantType_Object

  C (NPVariant with type:)   to   JavaScript
  NPVariantType_Void              undefined
  NPVariantType_Null              null
  NPVariantType_Bool              Boolean
  NPVariantType_Int32             Number
  NPVariantType_Double            Number
  NPVariantType_String            String
  NPVariantType_Object            Object
*/

typedef void *NPIdentifier;

/*
    NPObjects have methods and properties.  Methods and properties are
    identified with NPIdentifiers.  These identifiers may be reflected
    in script.  NPIdentifiers can be either strings or integers, IOW,
    methods and properties can be identified by either strings or
    integers (i.e. foo["bar"] vs foo[1]). NPIdentifiers can be
    compared using ==.  In case of any errors, the requested
    NPIdentifier(s) will be NULL. NPIdentifier lifetime is controlled
    by the browser. Plugins do not need to worry about memory management
    with regards to NPIdentifiers.
*/
NPIdentifier NPN_GetStringIdentifier(const NPUTF8 *name);
void NPN_GetStringIdentifiers(const NPUTF8 **names, int32_t nameCount,
                              NPIdentifier *identifiers);
NPIdentifier NPN_GetIntIdentifier(int32_t intid);
bool NPN_IdentifierIsString(NPIdentifier identifier);

/*
    The NPUTF8 returned from NPN_UTF8FromIdentifier SHOULD be freed.
*/
NPUTF8 *NPN_UTF8FromIdentifier(NPIdentifier identifier);

/*
    Get the integer represented by identifier. If identifier is not an
    integer identifier, the behaviour is undefined.
*/
int32_t NPN_IntFromIdentifier(NPIdentifier identifier);

/*
    NPObject behavior is implemented using the following set of
    callback functions.

    The NPVariant *result argument of these functions (where
    applicable) should be released using NPN_ReleaseVariantValue().
*/
typedef NPObject *(*NPAllocateFunctionPtr)(NPP npp, NPClass *aClass);
typedef void (*NPDeallocateFunctionPtr)(NPObject *npobj);
typedef void (*NPInvalidateFunctionPtr)(NPObject *npobj);
typedef bool (*NPHasMethodFunctionPtr)(NPObject *npobj, NPIdentifier name);
typedef bool (*NPInvokeFunctionPtr)(NPObject *npobj, NPIdentifier name,
                                    const NPVariant *args, uint32_t argCount,
                                    NPVariant *result);
typedef bool (*NPInvokeDefaultFunctionPtr)(NPObject *npobj,
                                           const NPVariant *args,
                                           uint32_t argCount,
                                           NPVariant *result);
typedef bool (*NPHasPropertyFunctionPtr)(NPObject *npobj, NPIdentifier name);
typedef bool (*NPGetPropertyFunctionPtr)(NPObject *npobj, NPIdentifier name,
                                         NPVariant *result);
typedef bool (*NPSetPropertyFunctionPtr)(NPObject *npobj, NPIdentifier name,
                                         const NPVariant *value);
typedef bool (*NPRemovePropertyFunctionPtr)(NPObject *npobj,
                                            NPIdentifier name);
typedef bool (*NPEnumerationFunctionPtr)(NPObject *npobj, NPIdentifier **value,
                                         uint32_t *count);
typedef bool (*NPConstructFunctionPtr)(NPObject *npobj,
                                       const NPVariant *args,
                                       uint32_t argCount,
                                       NPVariant *result);

/*
    NPObjects returned by create, retain, invoke, and getProperty pass
    a reference count to the caller.  That is, the callee adds a
    reference count which passes to the caller.  It is the caller's
    responsibility to release the returned object.

    NPInvokeFunctionPtr function may return 0 to indicate a void
    result.

    NPInvalidateFunctionPtr is called by the scripting environment
    when the native code is shutdown.  Any attempt to message a
    NPObject instance after the invalidate callback has been
    called will result in undefined behavior, even if the native code
    is still retaining those NPObject instances.  (The runtime
    will typically return immediately, with 0 or NULL, from an attempt
    to dispatch to a NPObject, but this behavior should not be
    depended upon.)

    The NPEnumerationFunctionPtr function may pass an array of
    NPIdentifiers back to the caller. The callee allocs the memory of
    the array using NPN_MemAlloc(), and it's the caller's responsibility
    to release it using NPN_MemFree().
*/
struct NPClass
{
    uint32_t structVersion;
    NPAllocateFunctionPtr allocate;
    NPDeallocateFunctionPtr deallocate;
    NPInvalidateFunctionPtr invalidate;
    NPHasMethodFunctionPtr hasMethod;
    NPInvokeFunctionPtr invoke;
    NPInvokeDefaultFunctionPtr invokeDefault;
    NPHasPropertyFunctionPtr hasProperty;
    NPGetPropertyFunctionPtr getProperty;
    NPSetPropertyFunctionPtr setProperty;
    NPRemovePropertyFunctionPtr removeProperty;
    NPEnumerationFunctionPtr enumerate;
    NPConstructFunctionPtr construct;
};

#define NP_CLASS_STRUCT_VERSION      3

#define NP_CLASS_STRUCT_VERSION_ENUM 2
#define NP_CLASS_STRUCT_VERSION_CTOR 3

#define NP_CLASS_STRUCT_VERSION_HAS_ENUM(npclass)   \
        ((npclass)->structVersion >= NP_CLASS_STRUCT_VERSION_ENUM)

#define NP_CLASS_STRUCT_VERSION_HAS_CTOR(npclass)   \
        ((npclass)->structVersion >= NP_CLASS_STRUCT_VERSION_CTOR)

struct NPObject {
    NPClass *_class;
    uint32_t referenceCount;
    /*
     * Additional space may be allocated here by types of NPObjects
     */
};

/*
    If the class has an allocate function, NPN_CreateObject invokes
    that function, otherwise a NPObject is allocated and
    returned. This method will initialize the referenceCount member of
    the NPObject to 1.
*/
NPObject *NPN_CreateObject(NPP npp, NPClass *aClass);

/*
    Increment the NPObject's reference count.
*/
NPObject *NPN_RetainObject(NPObject *npobj);

/*
    Decremented the NPObject's reference count.  If the reference
    count goes to zero, the class's destroy function is invoke if
    specified, otherwise the object is freed directly.
*/
void NPN_ReleaseObject(NPObject *npobj);

/*
    Functions to access script objects represented by NPObject.

    Calls to script objects are synchronous.  If a function returns a
    value, it will be supplied via the result NPVariant
    argument. Successful calls will return true, false will be
    returned in case of an error.

    Calls made from plugin code to script must be made from the thread
    on which the plugin was initialized.
*/

bool NPN_Invoke(NPP npp, NPObject *npobj, NPIdentifier methodName,
                const NPVariant *args, uint32_t argCount, NPVariant *result);
bool NPN_InvokeDefault(NPP npp, NPObject *npobj, const NPVariant *args,
                       uint32_t argCount, NPVariant *result);
bool NPN_Evaluate(NPP npp, NPObject *npobj, NPString *script,
                  NPVariant *result);
bool NPN_GetProperty(NPP npp, NPObject *npobj, NPIdentifier propertyName,
                     NPVariant *result);
bool NPN_SetProperty(NPP npp, NPObject *npobj, NPIdentifier propertyName,
                     const NPVariant *value);
bool NPN_RemoveProperty(NPP npp, NPObject *npobj, NPIdentifier propertyName);
bool NPN_HasProperty(NPP npp, NPObject *npobj, NPIdentifier propertyName);
bool NPN_HasMethod(NPP npp, NPObject *npobj, NPIdentifier methodName);
bool NPN_Enumerate(NPP npp, NPObject *npobj, NPIdentifier **identifier,
                   uint32_t *count);
bool NPN_Construct(NPP npp, NPObject *npobj, const NPVariant *args,
                   uint32_t argCount, NPVariant *result);

/*
    NPN_SetException may be called to trigger a script exception upon
    return from entry points into NPObjects.  Typical usage:

    NPN_SetException (npobj, message);
*/
void NPN_SetException(NPObject *npobj, const NPUTF8 *message);

#ifdef __cplusplus
}
#endif

#endif