tor-browser

ErrorObject.h (6177B)

---

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef vm_ErrorObject_h_
#define vm_ErrorObject_h_

#include "mozilla/Assertions.h"
#include "mozilla/Maybe.h"

#include <stdint.h>

#include "jspubtd.h"
#include "NamespaceImports.h"

#include "js/Class.h"
#include "js/ColumnNumber.h"  // JS::ColumnNumberOneOrigin
#include "js/ErrorReport.h"
#include "js/RootingAPI.h"
#include "js/TypeDecls.h"
#include "js/UniquePtr.h"
#include "js/Value.h"
#include "vm/JSObject.h"
#include "vm/NativeObject.h"

namespace js {

class ErrorObject : public NativeObject {
 static JSObject* createProto(JSContext* cx, JSProtoKey key);

 static JSObject* createConstructor(JSContext* cx, JSProtoKey key);

 static bool init(JSContext* cx, Handle<ErrorObject*> obj, JSExnType type,
                  UniquePtr<JSErrorReport> errorReport, HandleString fileName,
                  HandleObject stack, uint32_t sourceId, uint32_t lineNumber,
                  JS::ColumnNumberOneOrigin columnNumber, HandleString message,
                  Handle<mozilla::Maybe<JS::Value>> cause);

 static const ClassSpec classSpecs[JSEXN_ERROR_LIMIT];
 static const JSClass protoClasses[JSEXN_ERROR_LIMIT];

protected:
 static const uint32_t STACK_SLOT = 0;
 static const uint32_t ERROR_REPORT_SLOT = STACK_SLOT + 1;
 static const uint32_t FILENAME_SLOT = ERROR_REPORT_SLOT + 1;
 static const uint32_t LINENUMBER_SLOT = FILENAME_SLOT + 1;
 static const uint32_t COLUMNNUMBER_SLOT = LINENUMBER_SLOT + 1;
 static const uint32_t MESSAGE_SLOT = COLUMNNUMBER_SLOT + 1;
 static const uint32_t CAUSE_SLOT = MESSAGE_SLOT + 1;
 static const uint32_t SOURCEID_SLOT = CAUSE_SLOT + 1;

 static const uint32_t RESERVED_SLOTS = SOURCEID_SLOT + 1;

 // This slot is only used for errors that could be Wasm traps.
 static const uint32_t WASM_TRAP_SLOT = SOURCEID_SLOT + 1;
 static const uint32_t RESERVED_SLOTS_MAYBE_WASM_TRAP = WASM_TRAP_SLOT + 1;

public:
 static const JSClass classes[JSEXN_ERROR_LIMIT];

 static const JSClass* classForType(JSExnType type) {
   MOZ_ASSERT(type < JSEXN_ERROR_LIMIT);
   return &classes[type];
 }

 static bool isErrorClass(const JSClass* clasp) {
   return &classes[0] <= clasp && clasp < &classes[0] + std::size(classes);
 }

 // Create an error of the given type corresponding to the provided location
 // info.  If |message| is non-null, then the error will have a .message
 // property with that value; otherwise the error will have no .message
 // property.
 static ErrorObject* create(JSContext* cx, JSExnType type, HandleObject stack,
                            HandleString fileName, uint32_t sourceId,
                            uint32_t lineNumber,
                            JS::ColumnNumberOneOrigin columnNumber,
                            UniquePtr<JSErrorReport> report,
                            HandleString message,
                            Handle<mozilla::Maybe<JS::Value>> cause,
                            HandleObject proto = nullptr);

 /*
  * Assign the initial error shape to the empty object.  (This shape does
  * *not* include .message, which must be added separately if needed; see
  * ErrorObject::init.)
  */
 static SharedShape* assignInitialShape(JSContext* cx,
                                        Handle<ErrorObject*> obj);

 JSExnType type() const {
   MOZ_ASSERT(isErrorClass(getClass()));
   return static_cast<JSExnType>(getClass() - &classes[0]);
 }

 JSErrorReport* getErrorReport() const {
   const Value& slot = getReservedSlot(ERROR_REPORT_SLOT);
   if (slot.isUndefined()) {
     return nullptr;
   }
   return static_cast<JSErrorReport*>(slot.toPrivate());
 }

 JSErrorReport* getOrCreateErrorReport(JSContext* cx);

 inline JSString* fileName(JSContext* cx) const;
 inline uint32_t sourceId() const;

 // Line number (1-origin).
 inline uint32_t lineNumber() const;

 // Column number in UTF-16 code units.
 inline JS::ColumnNumberOneOrigin columnNumber() const;

 // Returns nullptr or a (possibly wrapped) SavedFrame object.
 inline JSObject* stack() const;

 JSString* getMessage() const {
   Value val = getReservedSlot(MESSAGE_SLOT);
   return val.isString() ? val.toString() : nullptr;
 }

 /*
  * Return Nothing if the error was created without an initial cause or if the
  * initial cause data property has been redefined to an accessor property.
  */
 mozilla::Maybe<Value> getCause() const {
   const auto& value = getReservedSlot(CAUSE_SLOT);
   if (value.isMagic(JS_ERROR_WITHOUT_CAUSE) || value.isPrivateGCThing()) {
     return mozilla::Nothing();
   }
   return mozilla::Some(value);
 }

 void setStackSlot(const Value& stack) {
   MOZ_ASSERT(stack.isObjectOrNull());
   setReservedSlot(STACK_SLOT, stack);
 }

 void setCauseSlot(const Value& cause) {
   MOZ_ASSERT(!cause.isMagic());
   MOZ_ASSERT(getCause().isSome());
   setReservedSlot(CAUSE_SLOT, cause);
 }

 // Getter and setter for the Error.prototype.stack accessor.
 static bool getStack(JSContext* cx, unsigned argc, Value* vp);
 static bool getStack_impl(JSContext* cx, const CallArgs& args);
 static bool setStack(JSContext* cx, unsigned argc, Value* vp);
 static bool setStack_impl(JSContext* cx, const CallArgs& args);

 // Used to distinguish errors created from Wasm traps.
 bool mightBeWasmTrap() const {
   return type() == JSEXN_WASMRUNTIMEERROR || type() == JSEXN_INTERNALERR;
 }
 bool fromWasmTrap() const {
   if (!mightBeWasmTrap()) {
     return false;
   } else {
     MOZ_ASSERT(JSCLASS_RESERVED_SLOTS(getClass()) > WASM_TRAP_SLOT);
     return getReservedSlot(WASM_TRAP_SLOT).toBoolean();
   }
 }
 void setFromWasmTrap();
};

JSString* ErrorToSource(JSContext* cx, HandleObject obj);

}  // namespace js

template <>
inline bool JSObject::is<js::ErrorObject>() const {
 return js::ErrorObject::isErrorClass(getClass());
}

#endif  // vm_ErrorObject_h_