// Copyright 2008 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/files/file_path.h"
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#include <ctype.h>
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#include "base/logging.h"
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#include "base/stl_util.h"
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namespace base {
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#if defined(FILE_PATH_USES_WIN_SEPARATORS)
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const FilePath::CharType FilePath::kSeparators[] = FILE_PATH_LITERAL("\\/");
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#else // FILE_PATH_USES_WIN_SEPARATORS
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const FilePath::CharType FilePath::kSeparators[] = FILE_PATH_LITERAL("/");
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#endif // FILE_PATH_USES_WIN_SEPARATORS
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const FilePath::CharType FilePath::kCurrentDirectory[] = FILE_PATH_LITERAL(".");
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const FilePath::CharType FilePath::kParentDirectory[] = FILE_PATH_LITERAL("..");
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const FilePath::CharType FilePath::kExtensionSeparator = FILE_PATH_LITERAL('.');
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typedef FilePath::StringType StringType;
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namespace {
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const FilePath::CharType kStringTerminator = FILE_PATH_LITERAL('\0');
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// If this FilePath contains a drive letter specification, returns the
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// position of the last character of the drive letter specification,
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// otherwise returns npos. This can only be true on Windows, when a pathname
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// begins with a letter followed by a colon. On other platforms, this always
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// returns npos.
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StringType::size_type FindDriveLetter(const StringType& path) {
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#if defined(FILE_PATH_USES_DRIVE_LETTERS)
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// This is dependent on an ASCII-based character set, but that's a
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// reasonable assumption. iswalpha can be too inclusive here.
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if (path.length() >= 2 && path[1] == L':' &&
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((path[0] >= L'A' && path[0] <= L'Z') ||
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(path[0] >= L'a' && path[0] <= L'z'))) {
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return 1;
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}
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#endif // FILE_PATH_USES_DRIVE_LETTERS
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return StringType::npos;
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}
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#if defined(FILE_PATH_USES_DRIVE_LETTERS)
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bool EqualDriveLetterCaseInsensitive(const StringType& a,
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const StringType& b) {
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size_t a_letter_pos = FindDriveLetter(a);
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size_t b_letter_pos = FindDriveLetter(b);
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if (a_letter_pos == StringType::npos || b_letter_pos == StringType::npos)
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return a == b;
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if (::tolower(a[0]) != ::tolower(b[0]))
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return false;
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StringType a_rest(a.substr(a_letter_pos + 1));
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StringType b_rest(b.substr(b_letter_pos + 1));
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return a_rest == b_rest;
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}
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#endif // defined(FILE_PATH_USES_DRIVE_LETTERS)
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bool IsPathAbsolute(const StringType& path) {
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#if defined(FILE_PATH_USES_DRIVE_LETTERS)
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StringType::size_type letter = FindDriveLetter(path);
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if (letter != StringType::npos) {
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// Look for a separator right after the drive specification.
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return path.length() > letter + 1 &&
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FilePath::IsSeparator(path[letter + 1]);
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}
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// Look for a pair of leading separators.
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return path.length() > 1 &&
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FilePath::IsSeparator(path[0]) && FilePath::IsSeparator(path[1]);
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#else // FILE_PATH_USES_DRIVE_LETTERS
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// Look for a separator in the first position.
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return path.length() > 0 && FilePath::IsSeparator(path[0]);
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#endif // FILE_PATH_USES_DRIVE_LETTERS
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}
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} // namespace
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FilePath::FilePath() {
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}
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FilePath::FilePath(const FilePath& that) : path_(that.path_) {
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}
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FilePath::FilePath(const StringType& path) : path_(path) {
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StringType::size_type nul_pos = path_.find(kStringTerminator);
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if (nul_pos != StringType::npos)
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path_.erase(nul_pos, StringType::npos);
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}
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FilePath::~FilePath() {
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}
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FilePath& FilePath::operator=(const FilePath& that) {
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path_ = that.path_;
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return *this;
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}
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bool FilePath::operator==(const FilePath& that) const {
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#if defined(FILE_PATH_USES_DRIVE_LETTERS)
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return EqualDriveLetterCaseInsensitive(this->path_, that.path_);
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#else // defined(FILE_PATH_USES_DRIVE_LETTERS)
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return path_ == that.path_;
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#endif // defined(FILE_PATH_USES_DRIVE_LETTERS)
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}
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bool FilePath::operator!=(const FilePath& that) const {
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#if defined(FILE_PATH_USES_DRIVE_LETTERS)
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return !EqualDriveLetterCaseInsensitive(this->path_, that.path_);
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#else // defined(FILE_PATH_USES_DRIVE_LETTERS)
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return path_ != that.path_;
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#endif // defined(FILE_PATH_USES_DRIVE_LETTERS)
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}
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// static
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bool FilePath::IsSeparator(CharType character) {
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for (size_t i = 0; i < size(FilePath::kSeparators) - 1; ++i) {
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if (character == kSeparators[i]) {
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return true;
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}
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}
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return false;
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}
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// libgen's dirname and basename aren't guaranteed to be thread-safe and aren't
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// guaranteed to not modify their input strings, and in fact are implemented
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// differently in this regard on different platforms. Don't use them, but
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// adhere to their behavior.
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FilePath FilePath::DirName() const {
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FilePath new_path(path_);
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new_path.StripTrailingSeparatorsInternal();
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// The drive letter, if any, always needs to remain in the output. If there
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// is no drive letter, as will always be the case on platforms which do not
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// support drive letters, letter will be npos, or -1, so the comparisons and
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// resizes below using letter will still be valid.
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StringType::size_type letter = FindDriveLetter(new_path.path_);
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StringType::size_type last_separator =
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new_path.path_.find_last_of(kSeparators, StringType::npos,
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size(kSeparators) - 1);
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if (last_separator == StringType::npos) {
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// path_ is in the current directory.
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new_path.path_.resize(letter + 1);
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} else if (last_separator == letter + 1) {
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// path_ is in the root directory.
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new_path.path_.resize(letter + 2);
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} else if (last_separator == letter + 2 &&
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IsSeparator(new_path.path_[letter + 1])) {
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// path_ is in "//" (possibly with a drive letter); leave the double
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// separator intact indicating alternate root.
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new_path.path_.resize(letter + 3);
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} else if (last_separator != 0) {
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// path_ is somewhere else, trim the basename.
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new_path.path_.resize(last_separator);
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}
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new_path.StripTrailingSeparatorsInternal();
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if (!new_path.path_.length())
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new_path.path_ = kCurrentDirectory;
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return new_path;
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}
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FilePath FilePath::BaseName() const {
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FilePath new_path(path_);
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new_path.StripTrailingSeparatorsInternal();
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// The drive letter, if any, is always stripped.
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StringType::size_type letter = FindDriveLetter(new_path.path_);
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if (letter != StringType::npos) {
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new_path.path_.erase(0, letter + 1);
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}
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// Keep everything after the final separator, but if the pathname is only
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// one character and it's a separator, leave it alone.
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StringType::size_type last_separator =
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new_path.path_.find_last_of(kSeparators, StringType::npos,
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size(kSeparators) - 1);
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if (last_separator != StringType::npos &&
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last_separator < new_path.path_.length() - 1) {
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new_path.path_.erase(0, last_separator + 1);
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}
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return new_path;
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}
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StringType FilePath::FinalExtension() const {
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StringType base(BaseName().value());
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// Special case "." and ".."
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if (base == FilePath::kCurrentDirectory || base == FilePath::kParentDirectory)
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return StringType();
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const StringType::size_type dot = base.rfind(FilePath::kExtensionSeparator);
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if (dot == StringType::npos)
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return StringType();
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return base.substr(dot, StringType::npos);
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}
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FilePath FilePath::RemoveFinalExtension() const {
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StringType extension = FinalExtension();
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if (FinalExtension().empty())
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return *this;
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return FilePath(path_.substr(0, path_.size() - extension.size()));
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}
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FilePath FilePath::Append(const StringType& component) const {
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const StringType* appended = &component;
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StringType without_nuls;
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StringType::size_type nul_pos = component.find(kStringTerminator);
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if (nul_pos != StringType::npos) {
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without_nuls = component.substr(0, nul_pos);
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appended = &without_nuls;
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}
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DCHECK(!IsPathAbsolute(*appended));
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if (path_.compare(kCurrentDirectory) == 0) {
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// Append normally doesn't do any normalization, but as a special case,
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// when appending to kCurrentDirectory, just return a new path for the
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// component argument. Appending component to kCurrentDirectory would
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// serve no purpose other than needlessly lengthening the path, and
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// it's likely in practice to wind up with FilePath objects containing
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// only kCurrentDirectory when calling DirName on a single relative path
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// component.
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return FilePath(*appended);
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}
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FilePath new_path(path_);
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new_path.StripTrailingSeparatorsInternal();
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// Don't append a separator if the path is empty (indicating the current
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// directory) or if the path component is empty (indicating nothing to
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// append).
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if (appended->length() > 0 && new_path.path_.length() > 0) {
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// Don't append a separator if the path still ends with a trailing
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// separator after stripping (indicating the root directory).
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if (!IsSeparator(new_path.path_[new_path.path_.length() - 1])) {
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// Don't append a separator if the path is just a drive letter.
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if (FindDriveLetter(new_path.path_) + 1 != new_path.path_.length()) {
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new_path.path_.append(1, kSeparators[0]);
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}
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}
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}
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new_path.path_.append(*appended);
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return new_path;
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}
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FilePath FilePath::Append(const FilePath& component) const {
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return Append(component.value());
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}
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bool FilePath::IsAbsolute() const {
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return IsPathAbsolute(path_);
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}
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void FilePath::StripTrailingSeparatorsInternal() {
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// If there is no drive letter, start will be 1, which will prevent stripping
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// the leading separator if there is only one separator. If there is a drive
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// letter, start will be set appropriately to prevent stripping the first
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// separator following the drive letter, if a separator immediately follows
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// the drive letter.
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StringType::size_type start = FindDriveLetter(path_) + 2;
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StringType::size_type last_stripped = StringType::npos;
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for (StringType::size_type pos = path_.length();
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pos > start && IsSeparator(path_[pos - 1]);
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--pos) {
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// If the string only has two separators and they're at the beginning,
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// don't strip them, unless the string began with more than two separators.
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if (pos != start + 1 || last_stripped == start + 2 ||
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!IsSeparator(path_[start - 1])) {
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path_.resize(pos - 1);
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last_stripped = pos;
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}
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}
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}
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} // namespace base
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void PrintTo(const base::FilePath& path, std::ostream* out) {
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*out << path.value().c_str();
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}
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