| // Copyright 2007, Google Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| // Canonicalization functions for the paths of URLs. |
| |
| #include "base/logging.h" |
| #include "googleurl/src/url_canon.h" |
| #include "googleurl/src/url_canon_internal.h" |
| #include "googleurl/src/url_parse_internal.h" |
| |
| namespace url_canon { |
| |
| namespace { |
| |
| enum CharacterFlags { |
| // Pass through unchanged, whether escaped or unescaped. This doesn't |
| // actually set anything so you can't OR it to check, it's just to make the |
| // table below more clear when neither ESCAPE or UNESCAPE is set. |
| PASS = 0, |
| |
| // This character requires special handling in DoPartialPath. Doing this test |
| // first allows us to filter out the common cases of regular characters that |
| // can be directly copied. |
| SPECIAL = 1, |
| |
| // This character must be escaped in the canonical output. Note that all |
| // escaped chars also have the "special" bit set so that the code that looks |
| // for this is triggered. Not valid with PASS or ESCAPE |
| ESCAPE_BIT = 2, |
| ESCAPE = ESCAPE_BIT | SPECIAL, |
| |
| // This character must be unescaped in canonical output. Not valid with |
| // ESCAPE or PASS. We DON'T set the SPECIAL flag since if we encounter these |
| // characters unescaped, they should just be copied. |
| UNESCAPE = 4, |
| |
| // This character is disallowed in URLs. Note that the "special" bit is also |
| // set to trigger handling. |
| INVALID_BIT = 8, |
| INVALID = INVALID_BIT | SPECIAL, |
| }; |
| |
| // This table contains one of the above flag values. Note some flags are more |
| // than one bits because they also turn on the "special" flag. Special is the |
| // only flag that may be combined with others. |
| // |
| // This table is designed to match exactly what IE does with the characters. |
| // |
| // Dot is even more special, and the escaped version is handled specially by |
| // IsDot. Therefore, we don't need the "escape" flag, and even the "unescape" |
| // bit is never handled (we just need the "special") bit. |
| const unsigned char kPathCharLookup[0x100] = { |
| // NULL control chars... |
| INVALID, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, |
| // control chars... |
| ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, |
| // ' ' ! " # $ % & ' ( ) * + , - . / |
| ESCAPE, PASS, ESCAPE, ESCAPE, PASS, ESCAPE, PASS, PASS, PASS, PASS, PASS, PASS, PASS, UNESCAPE,SPECIAL, PASS, |
| // 0 1 2 3 4 5 6 7 8 9 : ; < = > ? |
| UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,PASS, PASS, ESCAPE, PASS, ESCAPE, ESCAPE, |
| // @ A B C D E F G H I J K L M N O |
| PASS, UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE, |
| // P Q R S T U V W X Y Z [ \ ] ^ _ |
| UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,PASS, ESCAPE, PASS, ESCAPE, UNESCAPE, |
| // ` a b c d e f g h i j k l m n o |
| ESCAPE, UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE, |
| // p q r s t u v w x y z { | } ~ <NBSP> |
| UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,UNESCAPE,ESCAPE, ESCAPE, ESCAPE, UNESCAPE,ESCAPE, |
| // ...all the high-bit characters are escaped |
| ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, |
| ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, |
| ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, |
| ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, |
| ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, |
| ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, |
| ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, |
| ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE, ESCAPE}; |
| |
| enum DotDisposition { |
| // The given dot is just part of a filename and is not special. |
| NOT_A_DIRECTORY, |
| |
| // The given dot is the current directory. |
| DIRECTORY_CUR, |
| |
| // The given dot is the first of a double dot that should take us up one. |
| DIRECTORY_UP |
| }; |
| |
| // When the path resolver finds a dot, this function is called with the |
| // character following that dot to see what it is. The return value |
| // indicates what type this dot is (see above). This code handles the case |
| // where the dot is at the end of the input. |
| // |
| // |*consumed_len| will contain the number of characters in the input that |
| // express what we found. |
| // |
| // If the input is "../foo", |after_dot| = 1, |end| = 6, and |
| // at the end, |*consumed_len| = 2 for the "./" this function consumed. The |
| // original dot length should be handled by the caller. |
| template<typename CHAR> |
| DotDisposition ClassifyAfterDot(const CHAR* spec, int after_dot, |
| int end, int* consumed_len) { |
| if (after_dot == end) { |
| // Single dot at the end. |
| *consumed_len = 0; |
| return DIRECTORY_CUR; |
| } |
| if (url_parse::IsURLSlash(spec[after_dot])) { |
| // Single dot followed by a slash. |
| *consumed_len = 1; // Consume the slash |
| return DIRECTORY_CUR; |
| } |
| |
| int second_dot_len = IsDot(spec, after_dot, end); |
| if (second_dot_len) { |
| int after_second_dot = after_dot + second_dot_len; |
| if (after_second_dot == end) { |
| // Double dot at the end. |
| *consumed_len = second_dot_len; |
| return DIRECTORY_UP; |
| } |
| if (url_parse::IsURLSlash(spec[after_second_dot])) { |
| // Double dot followed by a slash. |
| *consumed_len = second_dot_len + 1; |
| return DIRECTORY_UP; |
| } |
| } |
| |
| // The dots are followed by something else, not a directory. |
| *consumed_len = 0; |
| return NOT_A_DIRECTORY; |
| } |
| |
| // Rewinds the output to the previous slash. It is assumed that the output |
| // ends with a slash and this doesn't count (we call this when we are |
| // appending directory paths, so the previous path component has and ending |
| // slash). |
| // |
| // This will stop at the first slash (assumed to be at position |
| // |path_begin_in_output| and not go any higher than that. Some web pages |
| // do ".." too many times, so we need to handle that brokenness. |
| // |
| // It searches for a literal slash rather than including a backslash as well |
| // because it is run only on the canonical output. |
| // |
| // The output is guaranteed to end in a slash when this function completes. |
| void BackUpToPreviousSlash(int path_begin_in_output, |
| CanonOutput* output) { |
| DCHECK(output->length() > 0); |
| |
| int i = output->length() - 1; |
| DCHECK(output->at(i) == '/'); |
| if (i == path_begin_in_output) |
| return; // We're at the first slash, nothing to do. |
| |
| // Now back up (skipping the trailing slash) until we find another slash. |
| i--; |
| while (output->at(i) != '/' && i > path_begin_in_output) |
| i--; |
| |
| // Now shrink the output to just include that last slash we found. |
| output->set_length(i + 1); |
| } |
| |
| // Appends the given path to the output. It assumes that if the input path |
| // starts with a slash, it should be copied to the output. If no path has |
| // already been appended to the output (the case when not resolving |
| // relative URLs), the path should begin with a slash. |
| // |
| // If there are already path components (this mode is used when appending |
| // relative paths for resolving), it assumes that the output already has |
| // a trailing slash and that if the input begins with a slash, it should be |
| // copied to the output. |
| // |
| // We do not collapse multiple slashes in a row to a single slash. It seems |
| // no web browsers do this, and we don't want incompababilities, even though |
| // it would be correct for most systems. |
| template<typename CHAR, typename UCHAR> |
| bool DoPartialPath(const CHAR* spec, |
| const url_parse::Component& path, |
| int path_begin_in_output, |
| CanonOutput* output) { |
| int end = path.end(); |
| |
| bool success = true; |
| for (int i = path.begin; i < end; i++) { |
| UCHAR uch = static_cast<UCHAR>(spec[i]); |
| if (sizeof(CHAR) > sizeof(char) && uch >= 0x80) { |
| // We only need to test wide input for having non-ASCII characters. For |
| // narrow input, we'll always just use the lookup table. We don't try to |
| // do anything tricky with decoding/validating UTF-8. This function will |
| // read one or two UTF-16 characters and append the output as UTF-8. This |
| // call will be removed in 8-bit mode. |
| success &= AppendUTF8EscapedChar(spec, &i, end, output); |
| } else { |
| // Normal ASCII character or 8-bit input, use the lookup table. |
| unsigned char out_ch = static_cast<unsigned char>(uch); |
| unsigned char flags = kPathCharLookup[out_ch]; |
| if (flags & SPECIAL) { |
| // Needs special handling of some sort. |
| int dotlen; |
| if ((dotlen = IsDot(spec, i, end)) > 0) { |
| // See if this dot was preceeded by a slash in the output. We |
| // assume that when canonicalizing paths, they will always |
| // start with a slash and not a dot, so we don't have to |
| // bounds check the output. |
| // |
| // Note that we check this in the case of dots so we don't have to |
| // special case slashes. Since slashes are much more common than |
| // dots, this actually increases performance measurably (though |
| // slightly). |
| DCHECK(output->length() > path_begin_in_output); |
| if (output->length() > path_begin_in_output && |
| output->at(output->length() - 1) == '/') { |
| // Slash followed by a dot, check to see if this is means relative |
| int consumed_len; |
| switch (ClassifyAfterDot<CHAR>(spec, i + dotlen, end, |
| &consumed_len)) { |
| case NOT_A_DIRECTORY: |
| // Copy the dot to the output, it means nothing special. |
| output->push_back('.'); |
| i += dotlen - 1; |
| break; |
| case DIRECTORY_CUR: // Current directory, just skip the input. |
| i += dotlen + consumed_len - 1; |
| break; |
| case DIRECTORY_UP: |
| BackUpToPreviousSlash(path_begin_in_output, output); |
| i += dotlen + consumed_len - 1; |
| break; |
| } |
| } else { |
| // This dot is not preceeded by a slash, it is just part of some |
| // file name. |
| output->push_back('.'); |
| i += dotlen - 1; |
| } |
| |
| } else if (out_ch == '\\') { |
| // Convert backslashes to forward slashes |
| output->push_back('/'); |
| |
| } else if (out_ch == '%') { |
| // Handle escape sequences. |
| unsigned char unescaped_value; |
| if (DecodeEscaped(spec, &i, end, &unescaped_value)) { |
| // Valid escape sequence, see if we keep, reject, or unescape it. |
| char unescaped_flags = kPathCharLookup[unescaped_value]; |
| |
| if (unescaped_flags & UNESCAPE) { |
| // This escaped value shouldn't be escaped, copy it. |
| output->push_back(unescaped_value); |
| } else if (unescaped_flags & INVALID_BIT) { |
| // Invalid escaped character, copy it and remember the error. |
| output->push_back('%'); |
| output->push_back(static_cast<char>(spec[i - 1])); |
| output->push_back(static_cast<char>(spec[i])); |
| success = false; |
| } else { |
| // Valid escaped character but we should keep it escaped. We |
| // don't want to change the case of any hex letters in case |
| // the server is sensitive to that, so we just copy the two |
| // characters without checking (DecodeEscape will have advanced |
| // to the last character of the pair). |
| output->push_back('%'); |
| output->push_back(static_cast<char>(spec[i - 1])); |
| output->push_back(static_cast<char>(spec[i])); |
| } |
| } else { |
| // Invalid escape sequence. IE7 rejects any URLs with such |
| // sequences, while Firefox, IE6, and Safari all pass it through |
| // unchanged. We are more permissive unlike IE7. I don't think this |
| // can cause significant problems, if it does, we should change |
| // to be more like IE7. |
| output->push_back('%'); |
| } |
| |
| } else if (flags & INVALID_BIT) { |
| // For NULLs, etc. fail. |
| AppendEscapedChar(out_ch, output); |
| success = false; |
| |
| } else if (flags & ESCAPE_BIT) { |
| // This character should be escaped. |
| AppendEscapedChar(out_ch, output); |
| } |
| } else { |
| // Nothing special about this character, just append it. |
| output->push_back(out_ch); |
| } |
| } |
| } |
| return success; |
| } |
| |
| template<typename CHAR, typename UCHAR> |
| bool DoPath(const CHAR* spec, |
| const url_parse::Component& path, |
| CanonOutput* output, |
| url_parse::Component* out_path) { |
| bool success = true; |
| if (path.len > 0) { |
| out_path->begin = output->length(); |
| |
| // Write out an initial slash if the input has none. If we just parse a URL |
| // and then canonicalize it, it will of course have a slash already. This |
| // check is for the replacement and relative URL resolving cases of file |
| // URLs. |
| if (!url_parse::IsURLSlash(spec[path.begin])) |
| output->push_back('/'); |
| |
| success = DoPartialPath<CHAR, UCHAR>(spec, path, out_path->begin, output); |
| out_path->len = output->length() - out_path->begin; |
| } else { |
| // No input, canonical path is a slash. |
| output->push_back('/'); |
| *out_path = url_parse::Component(); |
| } |
| return success; |
| } |
| |
| } // namespace |
| |
| bool CanonicalizePath(const char* spec, |
| const url_parse::Component& path, |
| CanonOutput* output, |
| url_parse::Component* out_path) { |
| return DoPath<char, unsigned char>(spec, path, output, out_path); |
| } |
| |
| bool CanonicalizePath(const char16* spec, |
| const url_parse::Component& path, |
| CanonOutput* output, |
| url_parse::Component* out_path) { |
| return DoPath<char16, char16>(spec, path, output, out_path); |
| } |
| |
| bool CanonicalizePartialPath(const char* spec, |
| const url_parse::Component& path, |
| int path_begin_in_output, |
| CanonOutput* output) { |
| return DoPartialPath<char, unsigned char>(spec, path, path_begin_in_output, |
| output); |
| } |
| |
| bool CanonicalizePartialPath(const char16* spec, |
| const url_parse::Component& path, |
| int path_begin_in_output, |
| CanonOutput* output) { |
| return DoPartialPath<char16, char16>(spec, path, path_begin_in_output, |
| output); |
| } |
| |
| } // namespace url_canon |
