js/src/vm/ErrorObject.h

   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 vm_ErrorObject_h_
   8 #define vm_ErrorObject_h_
   9
  10 #include "mozilla/Assertions.h"
  11 #include "mozilla/Maybe.h"
  12
  13 #include <iterator>
  14 #include <stdint.h>
  15
  16 #include "jspubtd.h"
  17 #include "NamespaceImports.h"
  18
  19 #include "js/Class.h"
  20 #include "js/ColumnNumber.h"  // JS::ColumnNumberOneOrigin
  21 #include "js/ErrorReport.h"
  22 #include "js/RootingAPI.h"
  23 #include "js/TypeDecls.h"
  24 #include "js/UniquePtr.h"
  25 #include "js/Value.h"
  26 #include "vm/JSObject.h"
  27 #include "vm/NativeObject.h"
  28
  29 namespace js {
  30
  31 class ErrorObject : public NativeObject {
  32   static JSObject* createProto(JSContext* cx, JSProtoKey key);
  33
  34   static JSObject* createConstructor(JSContext* cx, JSProtoKey key);
  35
  36   static bool init(JSContext* cx, Handle<ErrorObject*> obj, JSExnType type,
  37                    UniquePtr<JSErrorReport> errorReport, HandleString fileName,
  38                    HandleObject stack, uint32_t sourceId, uint32_t lineNumber,
  39                    JS::ColumnNumberOneOrigin columnNumber, HandleString message,
  40                    Handle<mozilla::Maybe<JS::Value>> cause);
  41
  42   static const ClassSpec classSpecs[JSEXN_ERROR_LIMIT];
  43   static const JSClass protoClasses[JSEXN_ERROR_LIMIT];
  44
  45  protected:
  46   static const uint32_t STACK_SLOT = 0;
  47   static const uint32_t ERROR_REPORT_SLOT = STACK_SLOT + 1;
  48   static const uint32_t FILENAME_SLOT = ERROR_REPORT_SLOT + 1;
  49   static const uint32_t LINENUMBER_SLOT = FILENAME_SLOT + 1;
  50   static const uint32_t COLUMNNUMBER_SLOT = LINENUMBER_SLOT + 1;
  51   static const uint32_t MESSAGE_SLOT = COLUMNNUMBER_SLOT + 1;
  52   static const uint32_t CAUSE_SLOT = MESSAGE_SLOT + 1;
  53   static const uint32_t SOURCEID_SLOT = CAUSE_SLOT + 1;
  54
  55   static const uint32_t RESERVED_SLOTS = SOURCEID_SLOT + 1;
  56
  57   // This slot is only used for errors that could be Wasm traps.
  58   static const uint32_t WASM_TRAP_SLOT = SOURCEID_SLOT + 1;
  59   static const uint32_t RESERVED_SLOTS_MAYBE_WASM_TRAP = WASM_TRAP_SLOT + 1;
  60
  61  public:
  62   static const JSClass classes[JSEXN_ERROR_LIMIT];
  63
  64   static const JSClass* classForType(JSExnType type) {
  65     MOZ_ASSERT(type < JSEXN_ERROR_LIMIT);
  66     return &classes[type];
  67   }
  68
  69   static bool isErrorClass(const JSClass* clasp) {
  70     return &classes[0] <= clasp && clasp < &classes[0] + std::size(classes);
  71   }
  72
  73   // Create an error of the given type corresponding to the provided location
  74   // info.  If |message| is non-null, then the error will have a .message
  75   // property with that value; otherwise the error will have no .message
  76   // property.
  77   static ErrorObject* create(JSContext* cx, JSExnType type, HandleObject stack,
  78                              HandleString fileName, uint32_t sourceId,
  79                              uint32_t lineNumber,
  80                              JS::ColumnNumberOneOrigin columnNumber,
  81                              UniquePtr<JSErrorReport> report,
  82                              HandleString message,
  83                              Handle<mozilla::Maybe<JS::Value>> cause,
  84                              HandleObject proto = nullptr);
  85
  86   /*
  87    * Assign the initial error shape to the empty object.  (This shape does
  88    * *not* include .message, which must be added separately if needed; see
  89    * ErrorObject::init.)
  90    */
  91   static SharedShape* assignInitialShape(JSContext* cx,
  92                                          Handle<ErrorObject*> obj);
  93
  94   JSExnType type() const {
  95     MOZ_ASSERT(isErrorClass(getClass()));
  96     return static_cast<JSExnType>(getClass() - &classes[0]);
  97   }
  98
  99   JSErrorReport* getErrorReport() const {
 100     const Value& slot = getReservedSlot(ERROR_REPORT_SLOT);
 101     if (slot.isUndefined()) {
 102       return nullptr;
 103     }
 104     return static_cast<JSErrorReport*>(slot.toPrivate());
 105   }
 106
 107   JSErrorReport* getOrCreateErrorReport(JSContext* cx);
 108
 109   inline JSString* fileName(JSContext* cx) const;
 110   inline uint32_t sourceId() const;
 111
 112   // Line number (1-origin).
 113   inline uint32_t lineNumber() const;
 114
 115   // Column number in UTF-16 code units.
 116   inline JS::ColumnNumberOneOrigin columnNumber() const;
 117
 118   // Returns nullptr or a (possibly wrapped) SavedFrame object.
 119   inline JSObject* stack() const;
 120
 121   JSString* getMessage() const {
 122     Value val = getReservedSlot(MESSAGE_SLOT);
 123     return val.isString() ? val.toString() : nullptr;
 124   }
 125
 126   /*
 127    * Return Nothing if the error was created without an initial cause or if the
 128    * initial cause data property has been redefined to an accessor property.
 129    */
 130   mozilla::Maybe<Value> getCause() const {
 131     const auto& value = getReservedSlot(CAUSE_SLOT);
 132     if (value.isMagic(JS_ERROR_WITHOUT_CAUSE) || value.isPrivateGCThing()) {
 133       return mozilla::Nothing();
 134     }
 135     return mozilla::Some(value);
 136   }
 137
 138   void setStackSlot(const Value& stack) {
 139     MOZ_ASSERT(stack.isObjectOrNull());
 140     setReservedSlot(STACK_SLOT, stack);
 141   }
 142
 143   void setCauseSlot(const Value& cause) {
 144     MOZ_ASSERT(!cause.isMagic());
 145     MOZ_ASSERT(getCause().isSome());
 146     setReservedSlot(CAUSE_SLOT, cause);
 147   }
 148
 149   // Getter and setter for the Error.prototype.stack accessor.
 150   static bool getStack(JSContext* cx, unsigned argc, Value* vp);
 151   static bool getStack_impl(JSContext* cx, const CallArgs& args);
 152   static bool setStack(JSContext* cx, unsigned argc, Value* vp);
 153   static bool setStack_impl(JSContext* cx, const CallArgs& args);
 154
 155   // Used to distinguish errors created from Wasm traps.
 156   bool mightBeWasmTrap() const {
 157     return type() == JSEXN_WASMRUNTIMEERROR || type() == JSEXN_INTERNALERR;
 158   }
 159   bool fromWasmTrap() const {
 160     if (!mightBeWasmTrap()) {
 161       return false;
 162     } else {
 163       MOZ_ASSERT(JSCLASS_RESERVED_SLOTS(getClass()) > WASM_TRAP_SLOT);
 164       return getReservedSlot(WASM_TRAP_SLOT).toBoolean();
 165     }
 166   }
 167   void setFromWasmTrap();
 168 };
 169
 170 JSString* ErrorToSource(JSContext* cx, HandleObject obj);
 171
 172 }  // namespace js
 173
 174 template <>
 175 inline bool JSObject::is<js::ErrorObject>() const {
 176   return js::ErrorObject::isErrorClass(getClass());
 177 }
 178
 179 #endif  // vm_ErrorObject_h_