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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/files/file_path.h"
#include <string.h>
#include <algorithm>
#include <iterator>
#include <string>
#include <string_view>
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "util/build_config.h"
#if defined(OS_MACOSX)
#include "base/mac/scoped_cftyperef.h"
#include "base/third_party/icu/icu_utf.h"
#endif
#if defined(OS_WIN)
#include <windows.h>
#elif defined(OS_MACOSX)
#include <CoreFoundation/CoreFoundation.h>
#endif
namespace base {
using StringType = FilePath::StringType;
using StringViewType = FilePath::StringViewType;
namespace {
const char* const kCommonDoubleExtensionSuffixes[] = {"gz", "z", "bz2", "bz"};
const char* const kCommonDoubleExtensions[] = {"user.js"};
const FilePath::CharType kStringTerminator = FILE_PATH_LITERAL('\0');
// If this FilePath contains a drive letter specification, returns the
// position of the last character of the drive letter specification,
// otherwise returns npos. This can only be true on Windows, when a pathname
// begins with a letter followed by a colon. On other platforms, this always
// returns npos.
StringViewType::size_type FindDriveLetter(StringViewType path) {
#if defined(FILE_PATH_USES_DRIVE_LETTERS)
// This is dependent on an ASCII-based character set, but that's a
// reasonable assumption. iswalpha can be too inclusive here.
if (path.length() >= 2 && path[1] == L':' &&
((path[0] >= L'A' && path[0] <= L'Z') ||
(path[0] >= L'a' && path[0] <= L'z'))) {
return 1;
}
#endif // FILE_PATH_USES_DRIVE_LETTERS
return StringType::npos;
}
#if defined(FILE_PATH_USES_DRIVE_LETTERS)
bool EqualDriveLetterCaseInsensitive(StringViewType a, StringViewType b) {
size_t a_letter_pos = FindDriveLetter(a);
size_t b_letter_pos = FindDriveLetter(b);
if (a_letter_pos == StringType::npos || b_letter_pos == StringType::npos)
return a == b;
StringViewType a_letter(a.substr(0, a_letter_pos + 1));
StringViewType b_letter(b.substr(0, b_letter_pos + 1));
if (!StartsWithCaseInsensitiveASCII(a_letter, b_letter))
return false;
StringViewType a_rest(a.substr(a_letter_pos + 1));
StringViewType b_rest(b.substr(b_letter_pos + 1));
return a_rest == b_rest;
}
#endif // defined(FILE_PATH_USES_DRIVE_LETTERS)
bool IsPathAbsolute(StringViewType path) {
#if defined(FILE_PATH_USES_DRIVE_LETTERS)
StringType::size_type letter = FindDriveLetter(path);
if (letter != StringType::npos) {
// Look for a separator right after the drive specification.
return path.length() > letter + 1 &&
FilePath::IsSeparator(path[letter + 1]);
}
// Look for a pair of leading separators.
return path.length() > 1 && FilePath::IsSeparator(path[0]) &&
FilePath::IsSeparator(path[1]);
#else // FILE_PATH_USES_DRIVE_LETTERS
// Look for a separator in the first position.
return path.length() > 0 && FilePath::IsSeparator(path[0]);
#endif // FILE_PATH_USES_DRIVE_LETTERS
}
bool AreAllSeparators(const StringType& input) {
for (StringType::const_iterator it = input.begin(); it != input.end(); ++it) {
if (!FilePath::IsSeparator(*it))
return false;
}
return true;
}
// Find the position of the '.' that separates the extension from the rest
// of the file name. The position is relative to BaseName(), not value().
// Returns npos if it can't find an extension.
StringType::size_type FinalExtensionSeparatorPosition(const StringType& path) {
// Special case "." and ".."
if (path == FilePath::kCurrentDirectory || path == FilePath::kParentDirectory)
return StringType::npos;
return path.rfind(FilePath::kExtensionSeparator);
}
// Same as above, but allow a second extension component of up to 4
// characters when the rightmost extension component is a common double
// extension (gz, bz2, Z). For example, foo.tar.gz or foo.tar.Z would have
// extension components of '.tar.gz' and '.tar.Z' respectively.
StringType::size_type ExtensionSeparatorPosition(const StringType& path) {
const StringType::size_type last_dot = FinalExtensionSeparatorPosition(path);
// No extension, or the extension is the whole filename.
if (last_dot == StringType::npos || last_dot == 0U)
return last_dot;
const StringType::size_type penultimate_dot =
path.rfind(FilePath::kExtensionSeparator, last_dot - 1);
const StringType::size_type last_separator = path.find_last_of(
FilePath::kSeparators, last_dot - 1, FilePath::kSeparatorsLength - 1);
if (penultimate_dot == StringType::npos ||
(last_separator != StringType::npos &&
penultimate_dot < last_separator)) {
return last_dot;
}
for (size_t i = 0; i < std::size(kCommonDoubleExtensions); ++i) {
StringType extension(path, penultimate_dot + 1);
if (LowerCaseEqualsASCII(extension, kCommonDoubleExtensions[i]))
return penultimate_dot;
}
StringType extension(path, last_dot + 1);
for (size_t i = 0; i < std::size(kCommonDoubleExtensionSuffixes); ++i) {
if (LowerCaseEqualsASCII(extension, kCommonDoubleExtensionSuffixes[i])) {
if ((last_dot - penultimate_dot) <= 5U &&
(last_dot - penultimate_dot) > 1U) {
return penultimate_dot;
}
}
}
return last_dot;
}
// Returns true if path is "", ".", or "..".
bool IsEmptyOrSpecialCase(const StringType& path) {
// Special cases "", ".", and ".."
if (path.empty() || path == FilePath::kCurrentDirectory ||
path == FilePath::kParentDirectory) {
return true;
}
return false;
}
} // namespace
FilePath::FilePath() = default;
FilePath::FilePath(const FilePath& that) = default;
FilePath::FilePath(FilePath&& that) noexcept = default;
FilePath::FilePath(StringViewType path) {
path_.assign(path);
StringType::size_type nul_pos = path_.find(kStringTerminator);
if (nul_pos != StringType::npos)
path_.erase(nul_pos, StringType::npos);
}
FilePath::~FilePath() = default;
FilePath& FilePath::operator=(const FilePath& that) = default;
FilePath& FilePath::operator=(FilePath&& that) = default;
bool FilePath::operator==(const FilePath& that) const {
#if defined(FILE_PATH_USES_DRIVE_LETTERS)
return EqualDriveLetterCaseInsensitive(this->path_, that.path_);
#else // defined(FILE_PATH_USES_DRIVE_LETTERS)
return path_ == that.path_;
#endif // defined(FILE_PATH_USES_DRIVE_LETTERS)
}
bool FilePath::operator!=(const FilePath& that) const {
#if defined(FILE_PATH_USES_DRIVE_LETTERS)
return !EqualDriveLetterCaseInsensitive(this->path_, that.path_);
#else // defined(FILE_PATH_USES_DRIVE_LETTERS)
return path_ != that.path_;
#endif // defined(FILE_PATH_USES_DRIVE_LETTERS)
}
// static
bool FilePath::IsSeparator(CharType character) {
for (size_t i = 0; i < kSeparatorsLength - 1; ++i) {
if (character == kSeparators[i]) {
return true;
}
}
return false;
}
void FilePath::GetComponents(std::vector<StringType>* components) const {
DCHECK(components);
if (!components)
return;
components->clear();
if (value().empty())
return;
std::vector<StringType> ret_val;
FilePath current = *this;
FilePath base;
// Capture path components.
while (current != current.DirName()) {
base = current.BaseName();
if (!AreAllSeparators(base.value()))
ret_val.push_back(base.value());
current = current.DirName();
}
// Capture root, if any.
base = current.BaseName();
if (!base.value().empty() && base.value() != kCurrentDirectory)
ret_val.push_back(current.BaseName().value());
// Capture drive letter, if any.
FilePath dir = current.DirName();
StringType::size_type letter = FindDriveLetter(dir.value());
if (letter != StringType::npos) {
ret_val.push_back(StringType(dir.value(), 0, letter + 1));
}
*components = std::vector<StringType>(ret_val.rbegin(), ret_val.rend());
}
bool FilePath::IsParent(const FilePath& child) const {
return AppendRelativePath(child, nullptr);
}
bool FilePath::AppendRelativePath(const FilePath& child, FilePath* path) const {
std::vector<StringType> parent_components;
std::vector<StringType> child_components;
GetComponents(&parent_components);
child.GetComponents(&child_components);
if (parent_components.empty() ||
parent_components.size() >= child_components.size())
return false;
std::vector<StringType>::const_iterator parent_comp =
parent_components.begin();
std::vector<StringType>::const_iterator child_comp = child_components.begin();
#if defined(FILE_PATH_USES_DRIVE_LETTERS)
// Windows can access case sensitive filesystems, so component
// comparisons must be case sensitive, but drive letters are
// never case sensitive.
if ((FindDriveLetter(*parent_comp) != StringType::npos) &&
(FindDriveLetter(*child_comp) != StringType::npos)) {
if (!StartsWithCaseInsensitiveASCII(*parent_comp, *child_comp))
return false;
++parent_comp;
++child_comp;
}
#endif // defined(FILE_PATH_USES_DRIVE_LETTERS)
while (parent_comp != parent_components.end()) {
if (*parent_comp != *child_comp)
return false;
++parent_comp;
++child_comp;
}
if (path != nullptr) {
for (; child_comp != child_components.end(); ++child_comp) {
*path = path->Append(*child_comp);
}
}
return true;
}
// libgen's dirname and basename aren't guaranteed to be thread-safe and aren't
// guaranteed to not modify their input strings, and in fact are implemented
// differently in this regard on different platforms. Don't use them, but
// adhere to their behavior.
FilePath FilePath::DirName() const {
FilePath new_path(path_);
new_path.StripTrailingSeparatorsInternal();
// The drive letter, if any, always needs to remain in the output. If there
// is no drive letter, as will always be the case on platforms which do not
// support drive letters, letter will be npos, or -1, so the comparisons and
// resizes below using letter will still be valid.
StringType::size_type letter = FindDriveLetter(new_path.path_);
StringType::size_type last_separator = new_path.path_.find_last_of(
kSeparators, StringType::npos, kSeparatorsLength - 1);
if (last_separator == StringType::npos) {
// path_ is in the current directory.
new_path.path_.resize(letter + 1);
} else if (last_separator == letter + 1) {
// path_ is in the root directory.
new_path.path_.resize(letter + 2);
} else if (last_separator == letter + 2 &&
IsSeparator(new_path.path_[letter + 1])) {
// path_ is in "//" (possibly with a drive letter); leave the double
// separator intact indicating alternate root.
new_path.path_.resize(letter + 3);
} else if (last_separator != 0) {
// path_ is somewhere else, trim the basename.
new_path.path_.resize(last_separator);
}
new_path.StripTrailingSeparatorsInternal();
if (!new_path.path_.length())
new_path.path_ = kCurrentDirectory;
return new_path;
}
FilePath FilePath::BaseName() const {
FilePath new_path(path_);
new_path.StripTrailingSeparatorsInternal();
// The drive letter, if any, is always stripped.
StringType::size_type letter = FindDriveLetter(new_path.path_);
if (letter != StringType::npos) {
new_path.path_.erase(0, letter + 1);
}
// Keep everything after the final separator, but if the pathname is only
// one character and it's a separator, leave it alone.
StringType::size_type last_separator = new_path.path_.find_last_of(
kSeparators, StringType::npos, kSeparatorsLength - 1);
if (last_separator != StringType::npos &&
last_separator < new_path.path_.length() - 1) {
new_path.path_.erase(0, last_separator + 1);
}
return new_path;
}
StringType FilePath::Extension() const {
FilePath base(BaseName());
const StringType::size_type dot = ExtensionSeparatorPosition(base.path_);
if (dot == StringType::npos)
return StringType();
return base.path_.substr(dot, StringType::npos);
}
StringType FilePath::FinalExtension() const {
FilePath base(BaseName());
const StringType::size_type dot = FinalExtensionSeparatorPosition(base.path_);
if (dot == StringType::npos)
return StringType();
return base.path_.substr(dot, StringType::npos);
}
FilePath FilePath::RemoveExtension() const {
if (Extension().empty())
return *this;
const StringType::size_type dot = ExtensionSeparatorPosition(path_);
if (dot == StringType::npos)
return *this;
return FilePath(path_.substr(0, dot));
}
FilePath FilePath::RemoveFinalExtension() const {
if (FinalExtension().empty())
return *this;
const StringType::size_type dot = FinalExtensionSeparatorPosition(path_);
if (dot == StringType::npos)
return *this;
return FilePath(path_.substr(0, dot));
}
FilePath FilePath::InsertBeforeExtension(StringViewType suffix) const {
if (suffix.empty())
return FilePath(path_);
if (IsEmptyOrSpecialCase(BaseName().value()))
return FilePath();
StringType ext = Extension();
StringType ret = RemoveExtension().value();
ret.append(suffix);
ret.append(ext);
return FilePath(ret);
}
FilePath FilePath::InsertBeforeExtensionASCII(std::string_view suffix) const {
DCHECK(IsStringASCII(suffix));
#if defined(OS_WIN)
return InsertBeforeExtension(ASCIIToUTF16(suffix));
#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
return InsertBeforeExtension(suffix);
#endif
}
FilePath FilePath::AddExtension(StringViewType extension) const {
if (IsEmptyOrSpecialCase(BaseName().value()))
return FilePath();
// If the new extension is "" or ".", then just return the current FilePath.
if (extension.empty() ||
(extension.size() == 1 && extension[0] == kExtensionSeparator))
return *this;
StringType str = path_;
if (extension[0] != kExtensionSeparator &&
*(str.end() - 1) != kExtensionSeparator) {
str.append(1, kExtensionSeparator);
}
str.append(extension);
return FilePath(str);
}
FilePath FilePath::ReplaceExtension(StringViewType extension) const {
if (IsEmptyOrSpecialCase(BaseName().value()))
return FilePath();
FilePath no_ext = RemoveExtension();
// If the new extension is "" or ".", then just remove the current extension.
if (extension.empty() ||
(extension.size() == 1 && extension[0] == kExtensionSeparator))
return no_ext;
StringType str = no_ext.value();
if (extension[0] != kExtensionSeparator)
str.append(1, kExtensionSeparator);
str.append(extension);
return FilePath(str);
}
FilePath FilePath::Append(StringViewType component) const {
StringViewType appended = component;
StringType without_nuls;
StringType::size_type nul_pos = component.find(kStringTerminator);
if (nul_pos != StringViewType::npos) {
without_nuls.assign(component.substr(0, nul_pos));
appended = StringViewType(without_nuls);
}
DCHECK(!IsPathAbsolute(appended));
if (path_.compare(kCurrentDirectory) == 0 && !appended.empty()) {
// Append normally doesn't do any normalization, but as a special case,
// when appending to kCurrentDirectory, just return a new path for the
// component argument. Appending component to kCurrentDirectory would
// serve no purpose other than needlessly lengthening the path, and
// it's likely in practice to wind up with FilePath objects containing
// only kCurrentDirectory when calling DirName on a single relative path
// component.
return FilePath(appended);
}
FilePath new_path(path_);
new_path.StripTrailingSeparatorsInternal();
// Don't append a separator if the path is empty (indicating the current
// directory) or if the path component is empty (indicating nothing to
// append).
if (!appended.empty() && !new_path.path_.empty()) {
// Don't append a separator if the path still ends with a trailing
// separator after stripping (indicating the root directory).
if (!IsSeparator(new_path.path_.back())) {
// Don't append a separator if the path is just a drive letter.
if (FindDriveLetter(new_path.path_) + 1 != new_path.path_.length()) {
new_path.path_.append(1, kSeparators[0]);
}
}
}
new_path.path_.append(appended);
return new_path;
}
FilePath FilePath::Append(const FilePath& component) const {
return Append(component.value());
}
FilePath FilePath::AppendASCII(std::string_view component) const {
DCHECK(base::IsStringASCII(component));
#if defined(OS_WIN)
return Append(ASCIIToUTF16(component));
#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
return Append(component);
#endif
}
bool FilePath::IsAbsolute() const {
return IsPathAbsolute(path_);
}
bool FilePath::EndsWithSeparator() const {
if (empty())
return false;
return IsSeparator(path_.back());
}
FilePath FilePath::AsEndingWithSeparator() const {
if (EndsWithSeparator() || path_.empty())
return *this;
StringType path_str;
path_str.reserve(path_.length() + 1); // Only allocate string once.
path_str = path_;
path_str.append(&kSeparators[0], 1);
return FilePath(path_str);
}
FilePath FilePath::StripTrailingSeparators() const {
FilePath new_path(path_);
new_path.StripTrailingSeparatorsInternal();
return new_path;
}
bool FilePath::ReferencesParent() const {
if (path_.find(kParentDirectory) == StringType::npos) {
// GetComponents is quite expensive, so avoid calling it in the majority
// of cases where there isn't a kParentDirectory anywhere in the path.
return false;
}
std::vector<StringType> components;
GetComponents(&components);
std::vector<StringType>::const_iterator it = components.begin();
for (; it != components.end(); ++it) {
const StringType& component = *it;
// Windows has odd, undocumented behavior with path components containing
// only whitespace and . characters. So, if all we see is . and
// whitespace, then we treat any .. sequence as referencing parent.
// For simplicity we enforce this on all platforms.
if (component.find_first_not_of(FILE_PATH_LITERAL(". \n\r\t")) ==
std::string::npos &&
component.find(kParentDirectory) != std::string::npos) {
return true;
}
}
return false;
}
#if defined(OS_WIN)
std::u16string FilePath::LossyDisplayName() const {
return path_;
}
std::string FilePath::MaybeAsASCII() const {
if (base::IsStringASCII(path_))
return UTF16ToASCII(path_);
return std::string();
}
std::string FilePath::As8Bit() const {
return UTF16ToUTF8(value());
}
#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
// See file_path.h for a discussion of the encoding of paths on POSIX
// platforms. These encoding conversion functions are not quite correct.
std::string FilePath::MaybeAsASCII() const {
if (base::IsStringASCII(path_))
return path_;
return std::string();
}
std::string FilePath::As8Bit() const {
return value();
}
#endif // defined(OS_WIN)
void FilePath::StripTrailingSeparatorsInternal() {
// If there is no drive letter, start will be 1, which will prevent stripping
// the leading separator if there is only one separator. If there is a drive
// letter, start will be set appropriately to prevent stripping the first
// separator following the drive letter, if a separator immediately follows
// the drive letter.
StringType::size_type start = FindDriveLetter(path_) + 2;
StringType::size_type last_stripped = StringType::npos;
for (StringType::size_type pos = path_.length();
pos > start && IsSeparator(path_[pos - 1]); --pos) {
// If the string only has two separators and they're at the beginning,
// don't strip them, unless the string began with more than two separators.
if (pos != start + 1 || last_stripped == start + 2 ||
!IsSeparator(path_[start - 1])) {
path_.resize(pos - 1);
last_stripped = pos;
}
}
}
FilePath FilePath::NormalizePathSeparators() const {
return NormalizePathSeparatorsTo(kSeparators[0]);
}
FilePath FilePath::NormalizePathSeparatorsTo(CharType separator) const {
#if defined(FILE_PATH_USES_WIN_SEPARATORS)
DCHECK_NE(static_cast<const void*>(kSeparators + kSeparatorsLength),
static_cast<const void*>(std::find(
kSeparators, kSeparators + kSeparatorsLength, separator)));
StringType copy = path_;
for (size_t i = 0; i < kSeparatorsLength; ++i) {
std::replace(copy.begin(), copy.end(), kSeparators[i], separator);
}
return FilePath(copy);
#else
return *this;
#endif
}
} // namespace base