tor-browser

The Tor Browser
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CTypes.h (3003B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
      2 * vim: set ts=8 sts=2 et sw=2 tw=80:
      3 * This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef js_experimental_CTypes_h
      8 #define js_experimental_CTypes_h
      9 
     10 #include "mozilla/Attributes.h"  // MOZ_RAII
     11 
     12 #include <stddef.h>  // size_t
     13 
     14 #include "jstypes.h"  // JS_PUBLIC_API
     15 
     16 #include "js/TypeDecls.h"
     17 
     18 namespace JS {
     19 
     20 #ifdef JS_HAS_CTYPES
     21 
     22 /**
     23 * Initialize the 'ctypes' object on a global variable 'obj'. The 'ctypes'
     24 * object will be sealed.
     25 */
     26 extern JS_PUBLIC_API bool InitCTypesClass(JSContext* cx,
     27                                          Handle<JSObject*> global);
     28 
     29 #endif  // JS_HAS_CTYPES
     30 
     31 /**
     32 * The type of ctypes activity that is occurring.
     33 */
     34 enum class CTypesActivityType {
     35  BeginCall,
     36  EndCall,
     37  BeginCallback,
     38  EndCallback,
     39 };
     40 
     41 /**
     42 * The signature of a function invoked at the leading or trailing edge of ctypes
     43 * activity.
     44 */
     45 using CTypesActivityCallback = void (*)(JSContext*, CTypesActivityType);
     46 
     47 /**
     48 * Sets a callback that is run whenever js-ctypes is about to be used when
     49 * calling into C.
     50 */
     51 extern JS_PUBLIC_API void SetCTypesActivityCallback(JSContext* cx,
     52                                                    CTypesActivityCallback cb);
     53 
     54 class MOZ_RAII JS_PUBLIC_API AutoCTypesActivityCallback {
     55 private:
     56  JSContext* cx;
     57  CTypesActivityCallback callback;
     58  CTypesActivityType endType;
     59 
     60 public:
     61  AutoCTypesActivityCallback(JSContext* cx, CTypesActivityType beginType,
     62                             CTypesActivityType endType);
     63 
     64  ~AutoCTypesActivityCallback() { DoEndCallback(); }
     65 
     66  void DoEndCallback() {
     67    if (callback) {
     68      callback(cx, endType);
     69      callback = nullptr;
     70    }
     71  }
     72 };
     73 
     74 #ifdef JS_HAS_CTYPES
     75 
     76 /**
     77 * Convert a unicode string 'source' of length 'slen' to the platform native
     78 * charset, returning a null-terminated string allocated with JS_malloc. On
     79 * failure, this function should report an error.
     80 */
     81 using CTypesUnicodeToNativeFun = char* (*)(JSContext*, const char16_t*, size_t);
     82 
     83 /**
     84 * Set of function pointers that ctypes can use for various internal functions.
     85 * See JS::SetCTypesCallbacks below. Providing nullptr for a function is safe
     86 * and will result in the applicable ctypes functionality not being available.
     87 */
     88 struct CTypesCallbacks {
     89  CTypesUnicodeToNativeFun unicodeToNative;
     90 };
     91 
     92 /**
     93 * Set the callbacks on the provided 'ctypesObj' object. 'callbacks' should be a
     94 * pointer to static data that exists for the lifetime of 'ctypesObj', but it
     95 * may safely be altered after calling this function and without having
     96 * to call this function again.
     97 */
     98 extern JS_PUBLIC_API void SetCTypesCallbacks(JSObject* ctypesObj,
     99                                             const CTypesCallbacks* callbacks);
    100 
    101 #endif  // JS_HAS_CTYPES
    102 
    103 }  // namespace JS
    104 
    105 #endif  // js_experimental_CTypes_h