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Diffstat (limited to '')
| -rw-r--r-- | xpcom/io/nsEscape.cpp | 664 |
1 files changed, 664 insertions, 0 deletions
diff --git a/xpcom/io/nsEscape.cpp b/xpcom/io/nsEscape.cpp new file mode 100644 index 0000000000..c1714c0b9a --- /dev/null +++ b/xpcom/io/nsEscape.cpp @@ -0,0 +1,664 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "nsEscape.h" + +#include "mozilla/ArrayUtils.h" +#include "mozilla/BinarySearch.h" +#include "mozilla/CheckedInt.h" +#include "mozilla/TextUtils.h" +#include "nsTArray.h" +#include "nsCRT.h" +#include "nsASCIIMask.h" + +static const char hexCharsUpper[] = "0123456789ABCDEF"; +static const char hexCharsUpperLower[] = "0123456789ABCDEFabcdef"; + +static const unsigned char netCharType[256] = + // clang-format off +/* Bit 0 xalpha -- the alphas +** Bit 1 xpalpha -- as xalpha but +** converts spaces to plus and plus to %2B +** Bit 3 ... path -- as xalphas but doesn't escape '/' +** Bit 4 ... NSURL-ref -- extra encoding for Apple NSURL compatibility. +** This encoding set is used on encoded URL ref +** components before converting a URL to an NSURL +** so we don't include '%' to avoid double encoding. +*/ + /* 0 1 2 3 4 5 6 7 8 9 A B C D E F */ + { 0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0, /* 0x */ + 0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0, /* 1x */ + /* ! " # $ % & ' ( ) * + , - . / */ + 0x0,0x8,0x0,0x0,0x8,0x8,0x8,0x8,0x8,0x8,0xf,0xc,0x8,0xf,0xf,0xc, /* 2x */ + /* 0 1 2 3 4 5 6 7 8 9 : ; < = > ? */ + 0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0x8,0x8,0x0,0x8,0x0,0x8, /* 3x */ + /* @ A B C D E F G H I J K L M N O */ + 0x8,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf, /* 4x */ + /* bits for '@' changed from 7 to 0 so '@' can be escaped */ + /* in usernames and passwords in publishing. */ + /* P Q R S T U V W X Y Z [ \ ] ^ _ */ + 0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0x0,0x0,0x0,0x0,0xf, /* 5x */ + /* ` a b c d e f g h i j k l m n o */ + 0x0,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf, /* 6x */ + /* p q r s t u v w x y z { | } ~ DEL */ + 0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf,0x0,0x0,0x0,0x8,0x0, /* 7x */ + 0x0, + }; + +/* decode % escaped hex codes into character values + */ +#define UNHEX(C) \ + ((C >= '0' && C <= '9') ? C - '0' : \ + ((C >= 'A' && C <= 'F') ? C - 'A' + 10 : \ + ((C >= 'a' && C <= 'f') ? C - 'a' + 10 : 0))) +// clang-format on + +#define IS_OK(C) (netCharType[((unsigned char)(C))] & (aFlags)) +#define HEX_ESCAPE '%' + +static const uint32_t ENCODE_MAX_LEN = 6; // %uABCD + +static uint32_t AppendPercentHex(char* aBuffer, unsigned char aChar) { + uint32_t i = 0; + aBuffer[i++] = '%'; + aBuffer[i++] = hexCharsUpper[aChar >> 4]; // high nibble + aBuffer[i++] = hexCharsUpper[aChar & 0xF]; // low nibble + return i; +} + +static uint32_t AppendPercentHex(char16_t* aBuffer, char16_t aChar) { + uint32_t i = 0; + aBuffer[i++] = '%'; + if (aChar & 0xff00) { + aBuffer[i++] = 'u'; + aBuffer[i++] = hexCharsUpper[aChar >> 12]; // high-byte high nibble + aBuffer[i++] = hexCharsUpper[(aChar >> 8) & 0xF]; // high-byte low nibble + } + aBuffer[i++] = hexCharsUpper[(aChar >> 4) & 0xF]; // low-byte high nibble + aBuffer[i++] = hexCharsUpper[aChar & 0xF]; // low-byte low nibble + return i; +} + +//---------------------------------------------------------------------------------------- +char* nsEscape(const char* aStr, size_t aLength, size_t* aOutputLength, + nsEscapeMask aFlags) +//---------------------------------------------------------------------------------------- +{ + if (!aStr) { + return nullptr; + } + + size_t charsToEscape = 0; + + const unsigned char* src = (const unsigned char*)aStr; + for (size_t i = 0; i < aLength; ++i) { + if (!IS_OK(src[i])) { + charsToEscape++; + } + } + + // calculate how much memory should be allocated + // original length + 2 bytes for each escaped character + terminating '\0' + // do the sum in steps to check for overflow + size_t dstSize = aLength + 1 + charsToEscape; + if (dstSize <= aLength) { + return nullptr; + } + dstSize += charsToEscape; + if (dstSize < aLength) { + return nullptr; + } + + // fail if we need more than 4GB + if (dstSize > UINT32_MAX) { + return nullptr; + } + + char* result = (char*)moz_xmalloc(dstSize); + + unsigned char* dst = (unsigned char*)result; + if (aFlags == url_XPAlphas) { + for (size_t i = 0; i < aLength; ++i) { + unsigned char c = *src++; + if (IS_OK(c)) { + *dst++ = c; + } else if (c == ' ') { + *dst++ = '+'; /* convert spaces to pluses */ + } else { + *dst++ = HEX_ESCAPE; + *dst++ = hexCharsUpper[c >> 4]; /* high nibble */ + *dst++ = hexCharsUpper[c & 0x0f]; /* low nibble */ + } + } + } else { + for (size_t i = 0; i < aLength; ++i) { + unsigned char c = *src++; + if (IS_OK(c)) { + *dst++ = c; + } else { + *dst++ = HEX_ESCAPE; + *dst++ = hexCharsUpper[c >> 4]; /* high nibble */ + *dst++ = hexCharsUpper[c & 0x0f]; /* low nibble */ + } + } + } + + *dst = '\0'; /* tack on eos */ + if (aOutputLength) { + *aOutputLength = dst - (unsigned char*)result; + } + + return result; +} + +//---------------------------------------------------------------------------------------- +char* nsUnescape(char* aStr) +//---------------------------------------------------------------------------------------- +{ + nsUnescapeCount(aStr); + return aStr; +} + +//---------------------------------------------------------------------------------------- +int32_t nsUnescapeCount(char* aStr) +//---------------------------------------------------------------------------------------- +{ + char* src = aStr; + char* dst = aStr; + + char c1[] = " "; + char c2[] = " "; + char* const pc1 = c1; + char* const pc2 = c2; + + if (!*src) { + // A null string was passed in. Nothing to escape. + // Returns early as the string might not actually be mutable with + // length 0. + return 0; + } + + while (*src) { + c1[0] = *(src + 1); + if (*(src + 1) == '\0') { + c2[0] = '\0'; + } else { + c2[0] = *(src + 2); + } + + if (*src != HEX_ESCAPE || strpbrk(pc1, hexCharsUpperLower) == nullptr || + strpbrk(pc2, hexCharsUpperLower) == nullptr) { + *dst++ = *src++; + } else { + src++; /* walk over escape */ + if (*src) { + *dst = UNHEX(*src) << 4; + src++; + } + if (*src) { + *dst = (*dst + UNHEX(*src)); + src++; + } + dst++; + } + } + + *dst = 0; + return (int)(dst - aStr); + +} /* NET_UnEscapeCnt */ + +void nsAppendEscapedHTML(const nsACString& aSrc, nsACString& aDst) { + // Preparation: aDst's length will increase by at least aSrc's length. If the + // addition overflows, we skip this, which is fine, and we'll likely abort + // while (infallibly) appending due to aDst becoming too large. + mozilla::CheckedInt<nsACString::size_type> newCapacity = aDst.Length(); + newCapacity += aSrc.Length(); + if (newCapacity.isValid()) { + aDst.SetCapacity(newCapacity.value()); + } + + for (auto cur = aSrc.BeginReading(); cur != aSrc.EndReading(); cur++) { + if (*cur == '<') { + aDst.AppendLiteral("<"); + } else if (*cur == '>') { + aDst.AppendLiteral(">"); + } else if (*cur == '&') { + aDst.AppendLiteral("&"); + } else if (*cur == '"') { + aDst.AppendLiteral("""); + } else if (*cur == '\'') { + aDst.AppendLiteral("'"); + } else { + aDst.Append(*cur); + } + } +} + +//---------------------------------------------------------------------------------------- +// +// The following table encodes which characters needs to be escaped for which +// parts of an URL. The bits are the "url components" in the enum EscapeMask, +// see nsEscape.h. + +template <size_t N> +static constexpr void AddUnescapedChars(const char (&aChars)[N], + uint32_t aFlags, + std::array<uint32_t, 256>& aTable) { + for (size_t i = 0; i < N - 1; ++i) { + aTable[static_cast<unsigned char>(aChars[i])] |= aFlags; + } +} + +static constexpr std::array<uint32_t, 256> BuildEscapeChars() { + constexpr uint32_t kAllModes = esc_Scheme | esc_Username | esc_Password | + esc_Host | esc_Directory | esc_FileBaseName | + esc_FileExtension | esc_Param | esc_Query | + esc_Ref | esc_ExtHandler; + + std::array<uint32_t, 256> table{0}; + + // Alphanumerics shouldn't be escaped in all escape modes. + AddUnescapedChars("0123456789", kAllModes, table); + AddUnescapedChars("ABCDEFGHIJKLMNOPQRSTUVWXYZ", kAllModes, table); + AddUnescapedChars("abcdefghijklmnopqrstuvwxyz", kAllModes, table); + AddUnescapedChars("!$&()*+,-_~", kAllModes, table); + + // Extra characters which aren't escaped in particular escape modes. + AddUnescapedChars(".", esc_Scheme, table); + // esc_Username has no additional unescaped characters. + AddUnescapedChars("|", esc_Password, table); + AddUnescapedChars(".", esc_Host, table); + AddUnescapedChars("'./:;=@[]|", esc_Directory, table); + AddUnescapedChars("'.:;=@[]|", esc_FileBaseName, table); + AddUnescapedChars("':;=@[]|", esc_FileExtension, table); + AddUnescapedChars(".:;=@[\\]^`{|}", esc_Param, table); + AddUnescapedChars("./:;=?@[\\]^`{|}", esc_Query, table); + AddUnescapedChars("#'./:;=?@[\\]^{|}", esc_Ref, table); + AddUnescapedChars("#'./:;=?@[]", esc_ExtHandler, table); + + return table; +} + +static constexpr std::array<uint32_t, 256> EscapeChars = BuildEscapeChars(); + +static bool dontNeedEscape(unsigned char aChar, uint32_t aFlags) { + return EscapeChars[(size_t)aChar] & aFlags; +} +static bool dontNeedEscape(uint16_t aChar, uint32_t aFlags) { + return aChar < EscapeChars.size() ? (EscapeChars[(size_t)aChar] & aFlags) + : false; +} + +// Temporary static assert to make sure that the rewrite to using +// `BuildEscapeChars` didn't change the final array in memory. +// It will be removed in Bug 1750945. + +static_assert([]() constexpr { + constexpr uint32_t OldEscapeChars[256] = + // clang-format off +// 0 1 2 3 4 5 6 7 8 9 A B C D E F +{ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0x + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 1x + 0,132095, 0,131584,132095, 0,132095,131696,132095,132095,132095,132095,132095,132095,132025,131856, // 2x !"#$%&'()*+,-./ + 132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132080,132080, 0,132080, 0,131840, // 3x 0123456789:;<=>? + 132080,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095, // 4x @ABCDEFGHIJKLMNO + 132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132080, 896,132080, 896,132095, // 5x PQRSTUVWXYZ[\]^_ + 384,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095, // 6x `abcdefghijklmno + 132095,132095,132095,132095,132095,132095,132095,132095,132095,132095,132095, 896, 1012, 896,132095, 0, // 7x pqrstuvwxyz{|}~ DEL + 0 // 80 to FF are zero +}; + // clang-format on + + for (size_t i = 0; i < EscapeChars.size(); ++i) { + if (OldEscapeChars[i] != EscapeChars[i]) { + return false; + } + } + return true; +}()); + +//---------------------------------------------------------------------------------------- + +/** + * Templated helper for URL escaping a portion of a string. + * + * @param aPart The pointer to the beginning of the portion of the string to + * escape. + * @param aPartLen The length of the string to escape. + * @param aFlags Flags used to configure escaping. @see EscapeMask + * @param aResult String that has the URL escaped portion appended to. Only + * altered if the string is URL escaped or |esc_AlwaysCopy| is specified. + * @param aDidAppend Indicates whether or not data was appended to |aResult|. + * @return NS_ERROR_INVALID_ARG, NS_ERROR_OUT_OF_MEMORY on failure. + */ +template <class T> +static nsresult T_EscapeURL(const typename T::char_type* aPart, size_t aPartLen, + uint32_t aFlags, const ASCIIMaskArray* aFilterMask, + T& aResult, bool& aDidAppend) { + typedef nsCharTraits<typename T::char_type> traits; + typedef typename traits::unsigned_char_type unsigned_char_type; + static_assert(sizeof(*aPart) == 1 || sizeof(*aPart) == 2, + "unexpected char type"); + + if (!aPart) { + MOZ_ASSERT_UNREACHABLE("null pointer"); + return NS_ERROR_INVALID_ARG; + } + + bool forced = !!(aFlags & esc_Forced); + bool ignoreNonAscii = !!(aFlags & esc_OnlyASCII); + bool ignoreAscii = !!(aFlags & esc_OnlyNonASCII); + bool writing = !!(aFlags & esc_AlwaysCopy); + bool colon = !!(aFlags & esc_Colon); + bool spaces = !!(aFlags & esc_Spaces); + + auto src = reinterpret_cast<const unsigned_char_type*>(aPart); + + typename T::char_type tempBuffer[100]; + unsigned int tempBufferPos = 0; + + bool previousIsNonASCII = false; + for (size_t i = 0; i < aPartLen; ++i) { + unsigned_char_type c = *src++; + + // If there is a filter, we wish to skip any characters which match it. + // This is needed so we don't perform an extra pass just to extract the + // filtered characters. + if (aFilterMask && mozilla::ASCIIMask::IsMasked(*aFilterMask, c)) { + if (!writing) { + if (!aResult.Append(aPart, i, mozilla::fallible)) { + return NS_ERROR_OUT_OF_MEMORY; + } + writing = true; + } + continue; + } + + // if the char has not to be escaped or whatever follows % is + // a valid escaped string, just copy the char. + // + // Also the % will not be escaped until forced + // See bugzilla bug 61269 for details why we changed this + // + // And, we will not escape non-ascii characters if requested. + // On special request we will also escape the colon even when + // not covered by the matrix. + // ignoreAscii is not honored for control characters (C0 and DEL) + // + // And, we should escape the '|' character when it occurs after any + // non-ASCII character as it may be aPart of a multi-byte character. + // + // 0x20..0x7e are the valid ASCII characters. + if ((dontNeedEscape(c, aFlags) || (c == HEX_ESCAPE && !forced) || + (c > 0x7f && ignoreNonAscii) || + (c >= 0x20 && c < 0x7f && ignoreAscii)) && + !(c == ':' && colon) && !(c == ' ' && spaces) && + !(previousIsNonASCII && c == '|' && !ignoreNonAscii)) { + if (writing) { + tempBuffer[tempBufferPos++] = c; + } + } else { /* do the escape magic */ + if (!writing) { + if (!aResult.Append(aPart, i, mozilla::fallible)) { + return NS_ERROR_OUT_OF_MEMORY; + } + writing = true; + } + uint32_t len = ::AppendPercentHex(tempBuffer + tempBufferPos, c); + tempBufferPos += len; + MOZ_ASSERT(len <= ENCODE_MAX_LEN, "potential buffer overflow"); + } + + // Flush the temp buffer if it doesnt't have room for another encoded char. + if (tempBufferPos >= mozilla::ArrayLength(tempBuffer) - ENCODE_MAX_LEN) { + NS_ASSERTION(writing, "should be writing"); + if (!aResult.Append(tempBuffer, tempBufferPos, mozilla::fallible)) { + return NS_ERROR_OUT_OF_MEMORY; + } + tempBufferPos = 0; + } + + previousIsNonASCII = (c > 0x7f); + } + if (writing) { + if (!aResult.Append(tempBuffer, tempBufferPos, mozilla::fallible)) { + return NS_ERROR_OUT_OF_MEMORY; + } + } + aDidAppend = writing; + return NS_OK; +} + +bool NS_EscapeURL(const char* aPart, int32_t aPartLen, uint32_t aFlags, + nsACString& aResult) { + size_t partLen; + if (aPartLen < 0) { + partLen = strlen(aPart); + } else { + partLen = aPartLen; + } + + return NS_EscapeURLSpan(mozilla::Span(aPart, partLen), aFlags, aResult); +} + +bool NS_EscapeURLSpan(mozilla::Span<const char> aStr, uint32_t aFlags, + nsACString& aResult) { + bool appended = false; + nsresult rv = T_EscapeURL(aStr.Elements(), aStr.Length(), aFlags, nullptr, + aResult, appended); + if (NS_FAILED(rv)) { + ::NS_ABORT_OOM(aResult.Length() * sizeof(nsACString::char_type)); + } + + return appended; +} + +nsresult NS_EscapeURL(const nsACString& aStr, uint32_t aFlags, + nsACString& aResult, const mozilla::fallible_t&) { + bool appended = false; + nsresult rv = T_EscapeURL(aStr.Data(), aStr.Length(), aFlags, nullptr, + aResult, appended); + if (NS_FAILED(rv)) { + aResult.Truncate(); + return rv; + } + + if (!appended) { + aResult = aStr; + } + + return rv; +} + +nsresult NS_EscapeAndFilterURL(const nsACString& aStr, uint32_t aFlags, + const ASCIIMaskArray* aFilterMask, + nsACString& aResult, + const mozilla::fallible_t&) { + bool appended = false; + nsresult rv = T_EscapeURL(aStr.Data(), aStr.Length(), aFlags, aFilterMask, + aResult, appended); + if (NS_FAILED(rv)) { + aResult.Truncate(); + return rv; + } + + if (!appended) { + if (!aResult.Assign(aStr, mozilla::fallible)) { + return NS_ERROR_OUT_OF_MEMORY; + } + } + + return rv; +} + +const nsAString& NS_EscapeURL(const nsAString& aStr, uint32_t aFlags, + nsAString& aResult) { + bool result = false; + nsresult rv = T_EscapeURL<nsAString>(aStr.Data(), aStr.Length(), aFlags, + nullptr, aResult, result); + + if (NS_FAILED(rv)) { + ::NS_ABORT_OOM(aResult.Length() * sizeof(nsAString::char_type)); + } + + if (result) { + return aResult; + } + return aStr; +} + +// Starting at aStr[aStart] find the first index in aStr that matches any +// character that is forbidden by aFunction. Return false if not found. +static bool FindFirstMatchFrom(const nsString& aStr, size_t aStart, + const std::function<bool(char16_t)>& aFunction, + size_t* aIndex) { + for (size_t j = aStart, l = aStr.Length(); j < l; ++j) { + if (aFunction(aStr[j])) { + *aIndex = j; + return true; + } + } + return false; +} + +const nsAString& NS_EscapeURL(const nsString& aStr, + const std::function<bool(char16_t)>& aFunction, + nsAString& aResult) { + bool didEscape = false; + for (size_t i = 0, strLen = aStr.Length(); i < strLen;) { + size_t j; + if (MOZ_UNLIKELY(FindFirstMatchFrom(aStr, i, aFunction, &j))) { + if (i == 0) { + didEscape = true; + aResult.Truncate(); + aResult.SetCapacity(aStr.Length()); + } + if (j != i) { + // The substring from 'i' up to 'j' that needs no escaping. + aResult.Append(nsDependentSubstring(aStr, i, j - i)); + } + char16_t buffer[ENCODE_MAX_LEN]; + uint32_t bufferLen = ::AppendPercentHex(buffer, aStr[j]); + MOZ_ASSERT(bufferLen <= ENCODE_MAX_LEN, "buffer overflow"); + aResult.Append(buffer, bufferLen); + i = j + 1; + } else { + if (MOZ_UNLIKELY(didEscape)) { + // The tail of the string that needs no escaping. + aResult.Append(nsDependentSubstring(aStr, i, strLen - i)); + } + break; + } + } + if (MOZ_UNLIKELY(didEscape)) { + return aResult; + } + return aStr; +} + +bool NS_UnescapeURL(const char* aStr, int32_t aLen, uint32_t aFlags, + nsACString& aResult) { + bool didAppend = false; + nsresult rv = + NS_UnescapeURL(aStr, aLen, aFlags, aResult, didAppend, mozilla::fallible); + if (rv == NS_ERROR_OUT_OF_MEMORY) { + ::NS_ABORT_OOM(aLen * sizeof(nsACString::char_type)); + } + + return didAppend; +} + +nsresult NS_UnescapeURL(const char* aStr, int32_t aLen, uint32_t aFlags, + nsACString& aResult, bool& aDidAppend, + const mozilla::fallible_t&) { + if (!aStr) { + MOZ_ASSERT_UNREACHABLE("null pointer"); + return NS_ERROR_INVALID_ARG; + } + + MOZ_ASSERT(aResult.IsEmpty(), + "Passing a non-empty string as an out parameter!"); + + uint32_t len; + if (aLen < 0) { + size_t stringLength = strlen(aStr); + if (stringLength >= UINT32_MAX) { + return NS_ERROR_OUT_OF_MEMORY; + } + len = stringLength; + } else { + len = aLen; + } + + bool ignoreNonAscii = !!(aFlags & esc_OnlyASCII); + bool ignoreAscii = !!(aFlags & esc_OnlyNonASCII); + bool writing = !!(aFlags & esc_AlwaysCopy); + bool skipControl = !!(aFlags & esc_SkipControl); + bool skipInvalidHostChar = !!(aFlags & esc_Host); + + unsigned char* destPtr; + uint32_t destPos; + + if (writing) { + if (!aResult.SetLength(len, mozilla::fallible)) { + return NS_ERROR_OUT_OF_MEMORY; + } + destPos = 0; + destPtr = reinterpret_cast<unsigned char*>(aResult.BeginWriting()); + } + + const char* last = aStr; + const char* end = aStr + len; + + for (const char* p = aStr; p < end; ++p) { + if (*p == HEX_ESCAPE && p + 2 < end) { + unsigned char c1 = *((unsigned char*)p + 1); + unsigned char c2 = *((unsigned char*)p + 2); + unsigned char u = (UNHEX(c1) << 4) + UNHEX(c2); + if (mozilla::IsAsciiHexDigit(c1) && mozilla::IsAsciiHexDigit(c2) && + (!skipInvalidHostChar || dontNeedEscape(u, aFlags) || c1 >= '8') && + ((c1 < '8' && !ignoreAscii) || (c1 >= '8' && !ignoreNonAscii)) && + !(skipControl && + (c1 < '2' || (c1 == '7' && (c2 == 'f' || c2 == 'F'))))) { + if (MOZ_UNLIKELY(!writing)) { + writing = true; + if (!aResult.SetLength(len, mozilla::fallible)) { + return NS_ERROR_OUT_OF_MEMORY; + } + destPos = 0; + destPtr = reinterpret_cast<unsigned char*>(aResult.BeginWriting()); + } + if (p > last) { + auto toCopy = p - last; + memcpy(destPtr + destPos, last, toCopy); + destPos += toCopy; + MOZ_ASSERT(destPos <= len); + last = p; + } + destPtr[destPos] = u; + destPos += 1; + MOZ_ASSERT(destPos <= len); + p += 2; + last += 3; + } + } + } + if (writing && last < end) { + auto toCopy = end - last; + memcpy(destPtr + destPos, last, toCopy); + destPos += toCopy; + MOZ_ASSERT(destPos <= len); + } + + if (writing) { + aResult.Truncate(destPos); + } + + aDidAppend = writing; + return NS_OK; +} |