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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /xpcom/io/nsEscape.cpp
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'xpcom/io/nsEscape.cpp')
-rw-r--r--xpcom/io/nsEscape.cpp634
1 files changed, 634 insertions, 0 deletions
diff --git a/xpcom/io/nsEscape.cpp b/xpcom/io/nsEscape.cpp
new file mode 100644
index 0000000000..f211ea2809
--- /dev/null
+++ b/xpcom/io/nsEscape.cpp
@@ -0,0 +1,634 @@
+/* -*- 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("&lt;");
+ } else if (*cur == '>') {
+ aDst.AppendLiteral("&gt;");
+ } else if (*cur == '&') {
+ aDst.AppendLiteral("&amp;");
+ } else if (*cur == '"') {
+ aDst.AppendLiteral("&quot;");
+ } else if (*cur == '\'') {
+ aDst.AppendLiteral("&#39;");
+ } 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);
+ // Note that behavior of esc_Username and esc_Password is the same, so these
+ // could be merged (in the URL spec, both reference the "userinfo encode set"
+ // https://url.spec.whatwg.org/#userinfo-percent-encode-set, so the same
+ // behavior is expected.)
+ // Leaving separate for now to minimize risk, as these are also IDL-exposed
+ // as separate constants.
+ AddUnescapedChars("'.", esc_Username, table);
+ AddUnescapedChars("'.", esc_Password, table);
+ AddUnescapedChars(".", esc_Host, table); // Same as esc_Scheme
+ 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;
+}
+
+//----------------------------------------------------------------------------------------
+
+/**
+ * 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;
+
+ 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)
+ //
+ // 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)) {
+ 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;
+ }
+ }
+ 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;
+}