tor-browser

The Tor Browser
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ErrorIPCUtils.h (3364B)

      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 file,
      5 * You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef IPC_ErrorIPCUtils_h
      8 #define IPC_ErrorIPCUtils_h
      9 
     10 #include <utility>
     11 
     12 #include "ipc/EnumSerializer.h"
     13 #include "ipc/IPCMessageUtils.h"
     14 #include "mozilla/Assertions.h"
     15 #include "mozilla/ErrorResult.h"
     16 
     17 namespace IPC {
     18 
     19 template <>
     20 struct ParamTraits<mozilla::dom::ErrNum>
     21    : public ContiguousEnumSerializer<
     22          mozilla::dom::ErrNum, mozilla::dom::ErrNum(0),
     23          mozilla::dom::ErrNum(mozilla::dom::Err_Limit)> {};
     24 
     25 template <>
     26 struct ParamTraits<mozilla::ErrorResult> {
     27  typedef mozilla::ErrorResult paramType;
     28 
     29  static void Write(MessageWriter* aWriter, const paramType& aParam) {
     30    // It should be the case that mMightHaveUnreportedJSException can only be
     31    // true when we're expecting a JS exception.  We cannot send such messages
     32    // over the IPC channel since there is no sane way of transferring the JS
     33    // value over to the other side.  Callers should never do that.
     34    MOZ_ASSERT_IF(aParam.IsJSException(),
     35                  aParam.mMightHaveUnreportedJSException);
     36    if (aParam.IsJSException()
     37 #ifdef DEBUG
     38        || aParam.mMightHaveUnreportedJSException
     39 #endif
     40    ) {
     41      MOZ_CRASH(
     42          "Cannot encode an ErrorResult representing a Javascript exception");
     43    }
     44 
     45    WriteParam(aWriter, aParam.mResult);
     46    WriteParam(aWriter, aParam.IsErrorWithMessage());
     47    WriteParam(aWriter, aParam.IsDOMException());
     48    if (aParam.IsErrorWithMessage()) {
     49      aParam.SerializeMessage(aWriter);
     50    } else if (aParam.IsDOMException()) {
     51      aParam.SerializeDOMExceptionInfo(aWriter);
     52    }
     53  }
     54 
     55  static void Write(MessageWriter* aWriter, paramType&& aParam) {
     56    Write(aWriter, static_cast<const paramType&>(aParam));
     57    aParam.SuppressException();
     58  }
     59 
     60  static bool Read(MessageReader* aReader, paramType* aResult) {
     61    paramType readValue;
     62    if (!ReadParam(aReader, &readValue.mResult)) {
     63      return false;
     64    }
     65    bool hasMessage = false;
     66    if (!ReadParam(aReader, &hasMessage)) {
     67      return false;
     68    }
     69    bool hasDOMExceptionInfo = false;
     70    if (!ReadParam(aReader, &hasDOMExceptionInfo)) {
     71      return false;
     72    }
     73    if (hasMessage && hasDOMExceptionInfo) {
     74      // Shouldn't have both!
     75      return false;
     76    }
     77    if (hasMessage && !readValue.DeserializeMessage(aReader)) {
     78      return false;
     79    } else if (hasDOMExceptionInfo &&
     80               !readValue.DeserializeDOMExceptionInfo(aReader)) {
     81      return false;
     82    }
     83    *aResult = std::move(readValue);
     84    return true;
     85  }
     86 };
     87 
     88 template <>
     89 struct ParamTraits<mozilla::CopyableErrorResult> {
     90  typedef mozilla::CopyableErrorResult paramType;
     91 
     92  static void Write(MessageWriter* aWriter, const paramType& aParam) {
     93    ParamTraits<mozilla::ErrorResult>::Write(aWriter, aParam);
     94  }
     95 
     96  static bool Read(MessageReader* aReader, paramType* aResult) {
     97    // We can't cast *aResult to ErrorResult&, so cheat and just cast
     98    // to ErrorResult*.
     99    return ParamTraits<mozilla::ErrorResult>::Read(
    100        aReader, reinterpret_cast<mozilla::ErrorResult*>(aResult));
    101  }
    102 };
    103 
    104 }  // namespace IPC
    105 
    106 #endif