widget/nsPrimitiveHelpers.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   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 //
   8 // Part of the reason these routines are all in once place is so that as new
   9 // data flavors are added that are known to be one-byte or two-byte strings, or
  10 // even raw binary data, then we just have to go to one place to change how the
  11 // data moves into/out of the primitives and native line endings.
  12 //
  13 // If you add new flavors that have special consideration (binary data or
  14 // one-byte char* strings), please update all the helper classes in this file.
  15 //
  16 // For now, this is the assumption that we are making:
  17 //  - text/plain is always a char*
  18 //  - anything else is a char16_t*
  19 //
  20
  21 #include "nsPrimitiveHelpers.h"
  22
  23 #include "mozilla/UniquePtr.h"
  24 #include "nsComponentManagerUtils.h"
  25 #include "nsCOMPtr.h"
  26 #include "nsXPCOM.h"
  27 #include "nsISupportsPrimitives.h"
  28 #include "nsITransferable.h"
  29 #include "nsLinebreakConverter.h"
  30 #include "nsReadableUtils.h"
  31
  32 //
  33 // CreatePrimitiveForData
  34 //
  35 // Given some data and the flavor it corresponds to, creates the appropriate
  36 // nsISupports* wrapper for passing across IDL boundaries. Right now, everything
  37 // creates a two-byte |nsISupportsString|, except for "text/plain" and native
  38 // platform HTML (CF_HTML on win32)
  39 //
  40 void nsPrimitiveHelpers ::CreatePrimitiveForData(const nsACString& aFlavor,
  41                                                  const void* aDataBuff,
  42                                                  uint32_t aDataLen,
  43                                                  nsISupports** aPrimitive) {
  44   if (!aPrimitive) return;
  45
  46   if (aFlavor.EqualsLiteral(kNativeHTMLMime) ||
  47       aFlavor.EqualsLiteral(kRTFMime) ||
  48       aFlavor.EqualsLiteral(kCustomTypesMime)) {
  49     nsCOMPtr<nsISupportsCString> primitive =
  50         do_CreateInstance(NS_SUPPORTS_CSTRING_CONTRACTID);
  51     if (primitive) {
  52       const char* start = reinterpret_cast<const char*>(aDataBuff);
  53       primitive->SetData(Substring(start, start + aDataLen));
  54       NS_ADDREF(*aPrimitive = primitive);
  55     }
  56   } else {
  57     nsCOMPtr<nsISupportsString> primitive =
  58         do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID);
  59     if (primitive) {
  60       if (aDataLen % 2) {
  61         auto buffer = mozilla::MakeUnique<char[]>(aDataLen + 1);
  62         if (!MOZ_LIKELY(buffer)) return;
  63
  64         memcpy(buffer.get(), aDataBuff, aDataLen);
  65         buffer[aDataLen] = 0;
  66         const char16_t* start = reinterpret_cast<const char16_t*>(buffer.get());
  67         // recall that length takes length as characters, not bytes
  68         primitive->SetData(Substring(start, start + (aDataLen + 1) / 2));
  69       } else {
  70         const char16_t* start = reinterpret_cast<const char16_t*>(aDataBuff);
  71         // recall that length takes length as characters, not bytes
  72         primitive->SetData(Substring(start, start + (aDataLen / 2)));
  73       }
  74       NS_ADDREF(*aPrimitive = primitive);
  75     }
  76   }
  77
  78 }  // CreatePrimitiveForData
  79
  80 //
  81 // CreatePrimitiveForCFHTML
  82 //
  83 // Platform specific CreatePrimitive, windows CF_HTML.
  84 //
  85 void nsPrimitiveHelpers ::CreatePrimitiveForCFHTML(const void* aDataBuff,
  86                                                    uint32_t* aDataLen,
  87                                                    nsISupports** aPrimitive) {
  88   if (!aPrimitive) return;
  89
  90   nsCOMPtr<nsISupportsString> primitive =
  91       do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID);
  92   if (!primitive) return;
  93
  94   // We need to duplicate the input buffer, since the removal of linebreaks
  95   // might reallocte it.
  96   void* utf8 = moz_xmalloc(*aDataLen);
  97   memcpy(utf8, aDataBuff, *aDataLen);
  98   int32_t signedLen = static_cast<int32_t>(*aDataLen);
  99   nsLinebreakHelpers::ConvertPlatformToDOMLinebreaks(true, &utf8, &signedLen);
 100   *aDataLen = signedLen;
 101
 102   nsAutoString str(
 103       NS_ConvertUTF8toUTF16(reinterpret_cast<const char*>(utf8), *aDataLen));
 104   free(utf8);
 105   *aDataLen = str.Length() * sizeof(char16_t);
 106   primitive->SetData(str);
 107   NS_ADDREF(*aPrimitive = primitive);
 108 }
 109
 110 //
 111 // CreateDataFromPrimitive
 112 //
 113 // Given a nsISupports* primitive and the flavor it represents, creates a new
 114 // data buffer with the data in it. This data will be null terminated, but the
 115 // length parameter does not reflect that.
 116 //
 117 void nsPrimitiveHelpers::CreateDataFromPrimitive(const nsACString& aFlavor,
 118                                                  nsISupports* aPrimitive,
 119                                                  void** aDataBuff,
 120                                                  uint32_t* aDataLen) {
 121   if (!aDataBuff) return;
 122
 123   *aDataBuff = nullptr;
 124   *aDataLen = 0;
 125
 126   if (aFlavor.EqualsLiteral(kCustomTypesMime)) {
 127     nsCOMPtr<nsISupportsCString> plainText(do_QueryInterface(aPrimitive));
 128     if (plainText) {
 129       nsAutoCString data;
 130       plainText->GetData(data);
 131       *aDataBuff = ToNewCString(data);
 132       *aDataLen = data.Length() * sizeof(char);
 133     }
 134   } else {
 135     nsCOMPtr<nsISupportsString> doubleByteText(do_QueryInterface(aPrimitive));
 136     if (doubleByteText) {
 137       nsAutoString data;
 138       doubleByteText->GetData(data);
 139       *aDataBuff = ToNewUnicode(data);
 140       *aDataLen = data.Length() * sizeof(char16_t);
 141     }
 142   }
 143 }
 144
 145 //
 146 // ConvertPlatformToDOMLinebreaks
 147 //
 148 // Given some data, convert from the platform linebreaks into the LF expected by
 149 // the DOM. This will attempt to convert the data in place, but the buffer may
 150 // still need to be reallocated regardless (disposing the old buffer is taken
 151 // care of internally, see the note below).
 152 //
 153 // NOTE: this assumes that it can use 'free' to dispose of the old buffer.
 154 //
 155 nsresult nsLinebreakHelpers ::ConvertPlatformToDOMLinebreaks(
 156     bool aIsSingleByteChars, void** ioData, int32_t* ioLengthInBytes) {
 157   NS_ASSERTION(ioData && *ioData && ioLengthInBytes, "Bad Params");
 158   if (!(ioData && *ioData && ioLengthInBytes)) return NS_ERROR_INVALID_ARG;
 159
 160   nsresult retVal = NS_OK;
 161
 162   // RTF and CF_HTML on Windows are transfered as single-byte characters.
 163   if (aIsSingleByteChars) {
 164     char* buffAsChars = reinterpret_cast<char*>(*ioData);
 165     char* oldBuffer = buffAsChars;
 166     retVal = nsLinebreakConverter::ConvertLineBreaksInSitu(
 167         &buffAsChars, nsLinebreakConverter::eLinebreakAny,
 168         nsLinebreakConverter::eLinebreakContent, *ioLengthInBytes,
 169         ioLengthInBytes);
 170     if (NS_SUCCEEDED(retVal)) {
 171       if (buffAsChars != oldBuffer)  // check if buffer was reallocated
 172         free(oldBuffer);
 173       *ioData = buffAsChars;
 174     }
 175   } else {
 176     char16_t* buffAsUnichar = reinterpret_cast<char16_t*>(*ioData);
 177     char16_t* oldBuffer = buffAsUnichar;
 178     int32_t newLengthInChars;
 179     retVal = nsLinebreakConverter::ConvertUnicharLineBreaksInSitu(
 180         &buffAsUnichar, nsLinebreakConverter::eLinebreakAny,
 181         nsLinebreakConverter::eLinebreakContent,
 182         *ioLengthInBytes / sizeof(char16_t), &newLengthInChars);
 183     if (NS_SUCCEEDED(retVal)) {
 184       if (buffAsUnichar != oldBuffer)  // check if buffer was reallocated
 185         free(oldBuffer);
 186       *ioData = buffAsUnichar;
 187       *ioLengthInBytes = newLengthInChars * sizeof(char16_t);
 188     }
 189   }
 190
 191   return retVal;
 192
 193 }  // ConvertPlatformToDOMLinebreaks