xpcom/io/nsScriptableInputStream.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 "nsScriptableInputStream.h"
   8 #include "nsMemory.h"
   9 #include "nsString.h"
  10
  11 NS_IMPL_ISUPPORTS(nsScriptableInputStream, nsIScriptableInputStream)
  12
  13 // nsIScriptableInputStream methods
  14 NS_IMETHODIMP
  15 nsScriptableInputStream::Close()
  16 {
  17   if (!mInputStream) {
  18     return NS_ERROR_NOT_INITIALIZED;
  19   }
  20   return mInputStream->Close();
  21 }
  22
  23 NS_IMETHODIMP
  24 nsScriptableInputStream::Init(nsIInputStream* aInputStream)
  25 {
  26   if (!aInputStream) {
  27     return NS_ERROR_NULL_POINTER;
  28   }
  29   mInputStream = aInputStream;
  30   return NS_OK;
  31 }
  32
  33 NS_IMETHODIMP
  34 nsScriptableInputStream::Available(uint64_t* aResult)
  35 {
  36   if (!mInputStream) {
  37     return NS_ERROR_NOT_INITIALIZED;
  38   }
  39   return mInputStream->Available(aResult);
  40 }
  41
  42 NS_IMETHODIMP
  43 nsScriptableInputStream::Read(uint32_t aCount, char** aResult)
  44 {
  45   nsresult rv = NS_OK;
  46   uint64_t count64 = 0;
  47   char* buffer = nullptr;
  48
  49   if (!mInputStream) {
  50     return NS_ERROR_NOT_INITIALIZED;
  51   }
  52
  53   rv = mInputStream->Available(&count64);
  54   if (NS_FAILED(rv)) {
  55     return rv;
  56   }
  57
  58   // bug716556 - Ensure count+1 doesn't overflow
  59   uint32_t count =
  60     XPCOM_MIN((uint32_t)XPCOM_MIN<uint64_t>(count64, aCount), UINT32_MAX - 1);
  61   buffer = (char*)moz_malloc(count + 1);  // make room for '\0'
  62   if (!buffer) {
  63     return NS_ERROR_OUT_OF_MEMORY;
  64   }
  65
  66   rv = ReadHelper(buffer, count);
  67   if (NS_FAILED(rv)) {
  68     nsMemory::Free(buffer);
  69     return rv;
  70   }
  71
  72   buffer[count] = '\0';
  73   *aResult = buffer;
  74   return NS_OK;
  75 }
  76
  77 NS_IMETHODIMP
  78 nsScriptableInputStream::ReadBytes(uint32_t aCount, nsACString& aResult)
  79 {
  80   if (!mInputStream) {
  81     return NS_ERROR_NOT_INITIALIZED;
  82   }
  83
  84   aResult.SetLength(aCount);
  85   if (aResult.Length() != aCount) {
  86     return NS_ERROR_OUT_OF_MEMORY;
  87   }
  88
  89   char* ptr = aResult.BeginWriting();
  90   nsresult rv = ReadHelper(ptr, aCount);
  91   if (NS_FAILED(rv)) {
  92     aResult.Truncate();
  93   }
  94   return rv;
  95 }
  96
  97 nsresult
  98 nsScriptableInputStream::ReadHelper(char* aBuffer, uint32_t aCount)
  99 {
 100   uint32_t totalBytesRead = 0;
 101   while (1) {
 102     uint32_t bytesRead;
 103     nsresult rv = mInputStream->Read(aBuffer + totalBytesRead,
 104                                      aCount - totalBytesRead,
 105                                      &bytesRead);
 106     if (NS_FAILED(rv)) {
 107       return rv;
 108     }
 109
 110     totalBytesRead += bytesRead;
 111     if (totalBytesRead == aCount) {
 112       break;
 113     }
 114
 115     // If we have read zero bytes, we have hit EOF.
 116     if (bytesRead == 0) {
 117       return NS_ERROR_FAILURE;
 118     }
 119
 120   }
 121   return NS_OK;
 122 }
 123
 124 nsresult
 125 nsScriptableInputStream::Create(nsISupports* aOuter, REFNSIID aIID,
 126                                 void** aResult)
 127 {
 128   if (aOuter) {
 129     return NS_ERROR_NO_AGGREGATION;
 130   }
 131
 132   nsScriptableInputStream* sis = new nsScriptableInputStream();
 133   if (!sis) {
 134     return NS_ERROR_OUT_OF_MEMORY;
 135   }
 136
 137   NS_ADDREF(sis);
 138   nsresult rv = sis->QueryInterface(aIID, aResult);
 139   NS_RELEASE(sis);
 140   return rv;
 141 }