Fix various problems with inline autocomplete and URLs that change length dur...

base/utf_string_conversions.cc

Index: base/utf_string_conversions.cc
===================================================================
--- base/utf_string_conversions.cc	(revision 31214)
+++ base/utf_string_conversions.cc	(working copy)
@@ -84,43 +84,50 @@
 
 // WriteUnicodeCharacter -------------------------------------------------------
 
-// Appends a UTF-8 character to the given 8-bit string.
-void WriteUnicodeCharacter(uint32 code_point, std::string* output) {
+// Appends a UTF-8 character to the given 8-bit string.  Returns the number of
+// bytes written.
+size_t WriteUnicodeCharacter(uint32 code_point, std::string* output) {
   if (code_point <= 0x7f) {
     // Fast path the common case of one byte.
     output->push_back(code_point);
-    return;
+    return 1;
   }
 
-  // U8_APPEND_UNSAFE can append up to 4 bytes.
-  int32 char_offset = static_cast<int32>(output->length());
+  // CBU8_APPEND_UNSAFE can append up to 4 bytes.
+  size_t char_offset = output->length();
+  size_t original_char_offset = char_offset;
   output->resize(char_offset + CBU8_MAX_LENGTH);
 
   CBU8_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
 
-  // U8_APPEND_UNSAFE will advance our pointer past the inserted character, so
+  // CBU8_APPEND_UNSAFE will advance our pointer past the inserted character, so
   // it will represent the new length of the string.
   output->resize(char_offset);
+  return char_offset - original_char_offset;
 }
 
-// Appends the given code point as a UTF-16 character to the STL string.
-void WriteUnicodeCharacter(uint32 code_point, string16* output) {
+// Appends the given code point as a UTF-16 character to the given 16-bit
+// string.  Returns the number of 16-bit values written.
+size_t WriteUnicodeCharacter(uint32 code_point, string16* output) {
   if (CBU16_LENGTH(code_point) == 1) {
     // Thie code point is in the Basic Multilingual Plane (BMP).
     output->push_back(static_cast<char16>(code_point));
-  } else {
-    // Non-BMP characters use a double-character encoding.
-    int32 char_offset = static_cast<int32>(output->length());
-    output->resize(char_offset + CBU16_MAX_LENGTH);
-    CBU16_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
+    return 1;
   }
+  // Non-BMP characters use a double-character encoding.
+  size_t char_offset = output->length();
+  output->resize(char_offset + CBU16_MAX_LENGTH);
+  CBU16_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
+  return CBU16_MAX_LENGTH;
 }
 
 #if defined(WCHAR_T_IS_UTF32)
-// Appends the given UTF-32 character to the given 32-bit string.
-inline void WriteUnicodeCharacter(uint32 code_point, std::wstring* output) {
+// Appends the given UTF-32 character to the given 32-bit string.  Returns the
+// number of 32-bit values written.
+inline size_t WriteUnicodeCharacter(uint32 code_point, std::wstring* output) {
   // This is the easy case, just append the character.
   output->push_back(code_point);
+  return 1;
 }
 #endif  // defined(WCHAR_T_IS_UTF32)
 
@@ -131,31 +138,57 @@
 // determine the source, and the given output STL string will be replaced by
 // the result.
 template<typename SRC_CHAR, typename DEST_STRING>
-bool ConvertUnicode(const SRC_CHAR* src, size_t src_len, DEST_STRING* output) {
-  output->clear();
+bool ConvertUnicode(const SRC_CHAR* src,
+                    size_t src_len,
+                    DEST_STRING* output,
+                    size_t* offset_for_adjustment) {
+  size_t output_offset =
+      (offset_for_adjustment && *offset_for_adjustment < src_len) ?
+          *offset_for_adjustment : DEST_STRING::npos;
 
   // ICU requires 32-bit numbers.
   bool success = true;
   int32 src_len32 = static_cast<int32>(src_len);
   for (int32 i = 0; i < src_len32; i++) {
     uint32 code_point;
+    size_t original_i = i;
+    size_t chars_written = 0;
     if (ReadUnicodeCharacter(src, src_len32, &i, &code_point)) {
-      WriteUnicodeCharacter(code_point, output);
+      chars_written = WriteUnicodeCharacter(code_point, output);
     } else {
       // TODO(jungshik): consider adding 'Replacement character' (U+FFFD)
       // in place of an invalid codepoint.
       success = false;
     }
+    if ((output_offset != DEST_STRING::npos) &&
+        (*offset_for_adjustment > original_i)) {
+      // NOTE: ReadUnicodeCharacter() adjusts |i| to point _at_ the last
+      // character read, not after it (so that incrementing it in the loop
+      // increment will place it at the right location), so we need to account
+      // for that in determining the amount that was read.
+      if (*offset_for_adjustment <= static_cast<size_t>(i))
+        output_offset = DEST_STRING::npos;
+      else
+        output_offset += chars_written - (i - original_i + 1);
+    }
   }
+
+  if (offset_for_adjustment)
+    *offset_for_adjustment = output_offset;
   return success;
 }
 
-// Guesses the length of the output in UTF-8 in bytes, and reserves that amount
-// of space in the given string. We also assume that the input character types
-// are unsigned, which will be true for UTF-16 and -32 on our systems. We assume
-// the string length is greater than zero.
+// Guesses the length of the output in UTF-8 in bytes, clears that output
+// string, and reserves that amount of space.  We assume that the input
+// character types are unsigned, which will be true for UTF-16 and -32 on our
+// systems.
 template<typename CHAR>
-void ReserveUTF8Output(const CHAR* src, size_t src_len, std::string* output) {
+void PrepareForUTF8Output(const CHAR* src,
+                          size_t src_len,
+                          std::string* output) {
+  output->clear();
+  if (src_len == 0)
+    return;
   if (src[0] < 0x80) {
     // Assume that the entire input will be ASCII.
     output->reserve(src_len);
@@ -165,11 +198,15 @@
   }
 }
 
-// Guesses the size of the output buffer (containing either UTF-16 or -32 data)
-// given some UTF-8 input that will be converted to it. See ReserveUTF8Output.
-// We assume the source length is > 0.
+// Prepares an output buffer (containing either UTF-16 or -32 data) given some
+// UTF-8 input that will be converted to it.  See PrepareForUTF8Output().
 template<typename STRING>
-void ReserveUTF16Or32Output(const char* src, size_t src_len, STRING* output) {
+void PrepareForUTF16Or32Output(const char* src,
+                               size_t src_len,
+                               STRING* output) {
+  output->clear();
+  if (src_len == 0)
+    return;
   if (static_cast<unsigned char>(src[0]) < 0x80) {
     // Assume the input is all ASCII, which means 1:1 correspondence.
     output->reserve(src_len);
@@ -184,113 +221,123 @@
 
 // UTF-8 <-> Wide --------------------------------------------------------------
 
-std::string WideToUTF8(const std::wstring& wide) {
+bool WideToUTF8AndAdjustOffset(const wchar_t* src,
+                               size_t src_len,
+                               std::string* output,
+                               size_t* offset_for_adjustment) {
+  PrepareForUTF8Output(src, src_len, output);
+  return ConvertUnicode<wchar_t, std::string>(src, src_len, output,
+                                              offset_for_adjustment);
+}
+
+std::string WideToUTF8AndAdjustOffset(const std::wstring& wide,
+                                      size_t* offset_for_adjustment) {
   std::string ret;
-  if (wide.empty())
-    return ret;
-
   // Ignore the success flag of this call, it will do the best it can for
   // invalid input, which is what we want here.
-  WideToUTF8(wide.data(), wide.length(), &ret);
+  WideToUTF8AndAdjustOffset(wide.data(), wide.length(), &ret,
+                            offset_for_adjustment);
   return ret;
 }
 
-bool WideToUTF8(const wchar_t* src, size_t src_len, std::string* output) {
-  if (src_len == 0) {
-    output->clear();
-    return true;
-  }
-
-  ReserveUTF8Output(src, src_len, output);
-  return ConvertUnicode<wchar_t, std::string>(src, src_len, output);
+bool UTF8ToWideAndAdjustOffset(const char* src,
+                               size_t src_len,
+                               std::wstring* output,
+                               size_t* offset_for_adjustment) {
+  PrepareForUTF16Or32Output(src, src_len, output);
+  return ConvertUnicode<char, std::wstring>(src, src_len, output,
+                                            offset_for_adjustment);
 }
 
-std::wstring UTF8ToWide(const base::StringPiece& utf8) {
+std::wstring UTF8ToWideAndAdjustOffset(const base::StringPiece& utf8,
+                                       size_t* offset_for_adjustment) {
   std::wstring ret;
-  if (utf8.empty())
-    return ret;
-
-  UTF8ToWide(utf8.data(), utf8.length(), &ret);
+  UTF8ToWideAndAdjustOffset(utf8.data(), utf8.length(), &ret,
+                            offset_for_adjustment);
   return ret;
 }
 
-bool UTF8ToWide(const char* src, size_t src_len, std::wstring* output) {
-  if (src_len == 0) {
-    output->clear();
-    return true;
-  }
-
-  ReserveUTF16Or32Output(src, src_len, output);
-  return ConvertUnicode<char, std::wstring>(src, src_len, output);
-}
-
 // UTF-16 <-> Wide -------------------------------------------------------------
 
 #if defined(WCHAR_T_IS_UTF16)
 
 // When wide == UTF-16, then conversions are a NOP.
-string16 WideToUTF16(const std::wstring& wide) {
-  return wide;
-}
-
-bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
+bool WideToUTF16AndAdjustOffset(const wchar_t* src,
+                                size_t src_len,
+                                string16* output,
+                                size_t* offset_for_adjustment) {
   output->assign(src, src_len);
+  if (offset_for_adjustment && (*offset_for_adjustment >= src_len))
+    *offset_for_adjustment = string16::npos;
   return true;
 }
 
-std::wstring UTF16ToWide(const string16& utf16) {
-  return utf16;
+string16 WideToUTF16AndAdjustOffset(const std::wstring& wide,
+                                    size_t* offset_for_adjustment) {
+  if (offset_for_adjustment && (*offset_for_adjustment >= wide.length()))
+    *offset_for_adjustment = string16::npos;
+  return wide;
 }
 
-bool UTF16ToWide(const char16* src, size_t src_len, std::wstring* output) {
+bool UTF16ToWideAndAdjustOffset(const char16* src,
+                                size_t src_len,
+                                std::wstring* output,
+                                size_t* offset_for_adjustment) {
   output->assign(src, src_len);
+  if (offset_for_adjustment && (*offset_for_adjustment >= src_len))
+    *offset_for_adjustment = std::wstring::npos;
   return true;
 }
 
-#elif defined(WCHAR_T_IS_UTF32)
-
-string16 WideToUTF16(const std::wstring& wide) {
-  string16 ret;
-  if (wide.empty())
-    return ret;
-
-  WideToUTF16(wide.data(), wide.length(), &ret);
-  return ret;
+std::wstring UTF16ToWideAndAdjustOffset(const string16& utf16,
+                                        size_t* offset_for_adjustment) {
+  if (offset_for_adjustment && (*offset_for_adjustment >= utf16.length()))
+    *offset_for_adjustment = std::wstring::npos;
+  return utf16;
 }
 
-bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
-  if (src_len == 0) {
-    output->clear();
-    return true;
-  }
+#elif defined(WCHAR_T_IS_UTF32)
 
+bool WideToUTF16AndAdjustOffset(const wchar_t* src,
+                                size_t src_len,
+                                string16* output,
+                                size_t* offset_for_adjustment) {
+  output->clear();
   // Assume that normally we won't have any non-BMP characters so the counts
   // will be the same.
   output->reserve(src_len);
-  return ConvertUnicode<wchar_t, string16>(src, src_len, output);
+  return ConvertUnicode<wchar_t, string16>(src, src_len, output,
+                                           offset_for_adjustment);
 }
 
-std::wstring UTF16ToWide(const string16& utf16) {
-  std::wstring ret;
-  if (utf16.empty())
-    return ret;
-
-  UTF16ToWide(utf16.data(), utf16.length(), &ret);
+string16 WideToUTF16AndAdjustOffset(const std::wstring& wide,
+                                    size_t* offset_for_adjustment) {
+  string16 ret;
+  WideToUTF16AndAdjustOffset(wide.data(), wide.length(), &ret,
+                             offset_for_adjustment);
   return ret;
 }
 
-bool UTF16ToWide(const char16* src, size_t src_len, std::wstring* output) {
-  if (src_len == 0) {
-    output->clear();
-    return true;
-  }
-
+bool UTF16ToWideAndAdjustOffset(const char16* src,
+                                size_t src_len,
+                                std::wstring* output,
+                                size_t* offset_for_adjustment) {
+  output->clear();
   // Assume that normally we won't have any non-BMP characters so the counts
   // will be the same.
   output->reserve(src_len);
-  return ConvertUnicode<char16, std::wstring>(src, src_len, output);
+  return ConvertUnicode<char16, std::wstring>(src, src_len, output,
+                                              offset_for_adjustment);
 }
 
+std::wstring UTF16ToWideAndAdjustOffset(const string16& utf16,
+                                        size_t* offset_for_adjustment) {
+  std::wstring ret;
+  UTF16ToWideAndAdjustOffset(utf16.data(), utf16.length(), &ret,
+                             offset_for_adjustment);
+  return ret;
+}
+
 #endif  // defined(WCHAR_T_IS_UTF32)
 
 // UTF16 <-> UTF8 --------------------------------------------------------------
@@ -298,20 +345,12 @@
 #if defined(WCHAR_T_IS_UTF32)
 
 bool UTF8ToUTF16(const char* src, size_t src_len, string16* output) {
-  if (src_len == 0) {
-    output->clear();
-    return true;
-  }
-
-  ReserveUTF16Or32Output(src, src_len, output);
-  return ConvertUnicode<char, string16>(src, src_len, output);
+  PrepareForUTF16Or32Output(src, src_len, output);
+  return ConvertUnicode<char, string16>(src, src_len, output, NULL);
 }
 
 string16 UTF8ToUTF16(const std::string& utf8) {
   string16 ret;
-  if (utf8.empty())
-    return ret;
-
   // Ignore the success flag of this call, it will do the best it can for
   // invalid input, which is what we want here.
   UTF8ToUTF16(utf8.data(), utf8.length(), &ret);
@@ -319,20 +358,12 @@
 }
 
 bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output) {
-  if (src_len == 0) {
-    output->clear();
-    return true;
-  }
-
-  ReserveUTF8Output(src, src_len, output);
-  return ConvertUnicode<char16, std::string>(src, src_len, output);
+  PrepareForUTF8Output(src, src_len, output);
+  return ConvertUnicode<char16, std::string>(src, src_len, output, NULL);
 }
 
 std::string UTF16ToUTF8(const string16& utf16) {
   std::string ret;
-  if (utf16.empty())
-    return ret;
-
   // Ignore the success flag of this call, it will do the best it can for
   // invalid input, which is what we want here.
   UTF16ToUTF8(utf16.data(), utf16.length(), &ret);