xpcom/io/nsUnicharInputStream.cpp

   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 #include "nsUnicharInputStream.h"
   8 #include "nsIInputStream.h"
   9 #include "nsString.h"
  10 #include "nsTArray.h"
  11 #include "nsCRT.h"
  12 #include "nsStreamUtils.h"
  13 #include "nsConverterInputStream.h"
  14 #include "mozilla/Attributes.h"
  15 #include <fcntl.h>
  16 #if defined(XP_WIN)
  17 #  include <io.h>
  18 #else
  19 #  include <unistd.h>
  20 #endif
  21
  22 #define STRING_BUFFER_SIZE 8192
  23
  24 class StringUnicharInputStream final : public nsIUnicharInputStream {
  25  public:
  26   explicit StringUnicharInputStream(const nsAString& aString)
  27       : mString(aString), mPos(0), mLen(aString.Length()) {}
  28
  29   NS_DECL_ISUPPORTS
  30   NS_DECL_NSIUNICHARINPUTSTREAM
  31
  32   nsString mString;
  33   uint32_t mPos;
  34   uint32_t mLen;
  35
  36  private:
  37   ~StringUnicharInputStream() = default;
  38 };
  39
  40 NS_IMETHODIMP
  41 StringUnicharInputStream::Read(char16_t* aBuf, uint32_t aCount,
  42                                uint32_t* aReadCount) {
  43   if (mPos >= mLen) {
  44     *aReadCount = 0;
  45     return NS_OK;
  46   }
  47   nsAString::const_iterator iter;
  48   mString.BeginReading(iter);
  49   const char16_t* us = iter.get();
  50   uint32_t amount = mLen - mPos;
  51   if (amount > aCount) {
  52     amount = aCount;
  53   }
  54   memcpy(aBuf, us + mPos, sizeof(char16_t) * amount);
  55   mPos += amount;
  56   *aReadCount = amount;
  57   return NS_OK;
  58 }
  59
  60 NS_IMETHODIMP
  61 StringUnicharInputStream::ReadSegments(nsWriteUnicharSegmentFun aWriter,
  62                                        void* aClosure, uint32_t aCount,
  63                                        uint32_t* aReadCount) {
  64   uint32_t bytesWritten;
  65   uint32_t totalBytesWritten = 0;
  66
  67   nsresult rv;
  68   aCount = XPCOM_MIN<uint32_t>(mString.Length() - mPos, aCount);
  69
  70   nsAString::const_iterator iter;
  71   mString.BeginReading(iter);
  72
  73   while (aCount) {
  74     rv = aWriter(this, aClosure, iter.get() + mPos, totalBytesWritten, aCount,
  75                  &bytesWritten);
  76
  77     if (NS_FAILED(rv)) {
  78       // don't propagate errors to the caller
  79       break;
  80     }
  81
  82     aCount -= bytesWritten;
  83     totalBytesWritten += bytesWritten;
  84     mPos += bytesWritten;
  85   }
  86
  87   *aReadCount = totalBytesWritten;
  88
  89   return NS_OK;
  90 }
  91
  92 NS_IMETHODIMP
  93 StringUnicharInputStream::ReadString(uint32_t aCount, nsAString& aString,
  94                                      uint32_t* aReadCount) {
  95   if (mPos >= mLen) {
  96     *aReadCount = 0;
  97     return NS_OK;
  98   }
  99   uint32_t amount = mLen - mPos;
 100   if (amount > aCount) {
 101     amount = aCount;
 102   }
 103   aString = Substring(mString, mPos, amount);
 104   mPos += amount;
 105   *aReadCount = amount;
 106   return NS_OK;
 107 }
 108
 109 nsresult StringUnicharInputStream::Close() {
 110   mPos = mLen;
 111   return NS_OK;
 112 }
 113
 114 NS_IMPL_ISUPPORTS(StringUnicharInputStream, nsIUnicharInputStream)
 115
 116 //----------------------------------------------------------------------
 117
 118 nsresult NS_NewUnicharInputStream(nsIInputStream* aStreamToWrap,
 119                                   nsIUnicharInputStream** aResult) {
 120   *aResult = nullptr;
 121
 122   // Create converter input stream
 123   RefPtr<nsConverterInputStream> it = new nsConverterInputStream();
 124   nsresult rv = it->Init(aStreamToWrap, "UTF-8", STRING_BUFFER_SIZE,
 125                          nsIConverterInputStream::ERRORS_ARE_FATAL);
 126   if (NS_FAILED(rv)) {
 127     return rv;
 128   }
 129
 130   it.forget(aResult);
 131   return NS_OK;
 132 }