dom/base/nsJSUtils.h

   1 /* -*- Mode: C++; tab-width: 2; 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 #ifndef nsJSUtils_h__
   7 #define nsJSUtils_h__
   8
   9 /**
  10  * This is not a generated file. It contains common utility functions
  11  * invoked from the JavaScript code generated from IDL interfaces.
  12  * The goal of the utility functions is to cut down on the size of
  13  * the generated code itself.
  14  */
  15
  16 #include "mozilla/Assertions.h"
  17
  18 #include "jsapi.h"
  19 #include "nsString.h"
  20
  21 class nsIScriptContext;
  22 class nsIScriptGlobalObject;
  23
  24 class nsJSUtils
  25 {
  26 public:
  27   static bool GetCallingLocation(JSContext* aContext, const char* *aFilename,
  28                                  uint32_t* aLineno);
  29
  30   static nsIScriptGlobalObject *GetStaticScriptGlobal(JSObject* aObj);
  31
  32   static nsIScriptContext *GetStaticScriptContext(JSObject* aObj);
  33
  34   static nsIScriptGlobalObject *GetDynamicScriptGlobal(JSContext *aContext);
  35
  36   static nsIScriptContext *GetDynamicScriptContext(JSContext *aContext);
  37
  38   /**
  39    * Retrieve the inner window ID based on the given JSContext.
  40    *
  41    * @param JSContext aContext
  42    *        The JSContext from which you want to find the inner window ID.
  43    *
  44    * @returns uint64_t the inner window ID.
  45    */
  46   static uint64_t GetCurrentlyRunningCodeInnerWindowID(JSContext *aContext);
  47
  48   /**
  49    * Report a pending exception on aContext, if any.  Note that this
  50    * can be called when the context has a JS stack.  If that's the
  51    * case, the stack will be set aside before reporting the exception.
  52    */
  53   static void ReportPendingException(JSContext *aContext);
  54
  55   static nsresult CompileFunction(JSContext* aCx,
  56                                   JS::Handle<JSObject*> aTarget,
  57                                   JS::CompileOptions& aOptions,
  58                                   const nsACString& aName,
  59                                   uint32_t aArgCount,
  60                                   const char** aArgArray,
  61                                   const nsAString& aBody,
  62                                   JSObject** aFunctionObject);
  63
  64   struct EvaluateOptions {
  65     bool coerceToString;
  66     bool reportUncaught;
  67
  68     explicit EvaluateOptions() : coerceToString(false)
  69                                , reportUncaught(true)
  70     {}
  71
  72     EvaluateOptions& setCoerceToString(bool aCoerce) {
  73       coerceToString = aCoerce;
  74       return *this;
  75     }
  76
  77     EvaluateOptions& setReportUncaught(bool aReport) {
  78       reportUncaught = aReport;
  79       return *this;
  80     }
  81   };
  82
  83   static nsresult EvaluateString(JSContext* aCx,
  84                                  const nsAString& aScript,
  85                                  JS::Handle<JSObject*> aScopeObject,
  86                                  JS::CompileOptions &aCompileOptions,
  87                                  EvaluateOptions& aEvaluateOptions,
  88                                  JS::Value* aRetValue,
  89                                  void **aOffThreadToken = nullptr);
  90
  91 };
  92
  93
  94 class nsDependentJSString : public nsDependentString
  95 {
  96 public:
  97   /**
  98    * In the case of string ids, getting the string's chars is infallible, so
  99    * the dependent string can be constructed directly.
 100    */
 101   explicit nsDependentJSString(JS::Handle<jsid> id)
 102     : nsDependentString(JS_GetInternedStringChars(JSID_TO_STRING(id)),
 103                         JS_GetStringLength(JSID_TO_STRING(id)))
 104   {
 105   }
 106
 107   /**
 108    * Ditto for flat strings.
 109    */
 110   explicit nsDependentJSString(JSFlatString* fstr)
 111     : nsDependentString(JS_GetFlatStringChars(fstr),
 112                         JS_GetStringLength(JS_FORGET_STRING_FLATNESS(fstr)))
 113   {
 114   }
 115
 116   /**
 117    * For all other strings, the nsDependentJSString object should be default
 118    * constructed, which leaves it empty (this->IsEmpty()), and initialized with
 119    * one of the init() methods below.
 120    */
 121
 122   nsDependentJSString()
 123   {
 124   }
 125
 126   bool init(JSContext* aContext, JSString* str)
 127   {
 128       size_t length;
 129       const jschar* chars = JS_GetStringCharsZAndLength(aContext, str, &length);
 130       if (!chars)
 131           return false;
 132
 133       NS_ASSERTION(IsEmpty(), "init() on initialized string");
 134       nsDependentString* base = this;
 135       new(base) nsDependentString(chars, length);
 136       return true;
 137   }
 138
 139   bool init(JSContext* aContext, const JS::Value &v)
 140   {
 141       return init(aContext, JSVAL_TO_STRING(v));
 142   }
 143
 144   void init(JSFlatString* fstr)
 145   {
 146       MOZ_ASSERT(IsEmpty(), "init() on initialized string");
 147       new(this) nsDependentJSString(fstr);
 148   }
 149
 150   ~nsDependentJSString()
 151   {
 152   }
 153 };
 154
 155 #endif /* nsJSUtils_h__ */