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/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "path.h"
#include <android-base/strings.h>
#include <android-base/logging.h>
#include <algorithm>
#include <iterator>
#include <limits>
#include <memory>
#include <dirent.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
using namespace std::literals;
namespace android::incremental::path {
bool PathCharsLess::operator()(char l, char r) const {
int ll = l == '/' ? std::numeric_limits<char>::min() - 1 : l;
int rr = r == '/' ? std::numeric_limits<char>::min() - 1 : r;
return ll < rr;
}
bool PathLess::operator()(std::string_view l, std::string_view r) const {
return std::lexicographical_compare(std::begin(l), std::end(l), std::begin(r), std::end(r),
PathCharsLess());
}
static void preparePathComponent(std::string_view& path, bool trimAll) {
// need to check for double front slash as a single one has a separate meaning in front
while (!path.empty() && path.front() == '/' &&
(trimAll || (path.size() > 1 && path[1] == '/'))) {
path.remove_prefix(1);
}
// for the back we don't care about double-vs-single slash difference
while (path.size() > !trimAll && path.back() == '/') {
path.remove_suffix(1);
}
}
void details::append_next_path(std::string& target, std::string_view path) {
preparePathComponent(path, !target.empty());
if (path.empty()) {
return;
}
if (!target.empty() && !target.ends_with('/')) {
target.push_back('/');
}
target += path;
}
std::string_view relativize(std::string_view parent, std::string_view nested) {
if (!nested.starts_with(parent)) {
return nested;
}
if (nested.size() == parent.size()) {
return {};
}
if (nested[parent.size()] != '/') {
return nested;
}
auto relative = nested.substr(parent.size());
while (relative.front() == '/') {
relative.remove_prefix(1);
}
return relative;
}
bool isAbsolute(std::string_view path) {
return !path.empty() && path[0] == '/';
}
std::string normalize(std::string_view path) {
if (path.empty()) {
return {};
}
if (path.starts_with("../"sv)) {
return {};
}
std::string result;
if (isAbsolute(path)) {
path.remove_prefix(1);
} else {
char buffer[PATH_MAX];
if (!::getcwd(buffer, sizeof(buffer))) {
return {};
}
result += buffer;
}
size_t start = 0;
size_t end = 0;
for (; end != path.npos; start = end + 1) {
end = path.find('/', start);
// Next component, excluding the separator
auto part = path.substr(start, end - start);
if (part.empty() || part == "."sv) {
continue;
}
if (part == ".."sv) {
if (result.empty()) {
return {};
}
auto lastPos = result.rfind('/');
if (lastPos == result.npos) {
result.clear();
} else {
result.resize(lastPos);
}
continue;
}
result += '/';
result += part;
}
return result;
}
std::string_view basename(std::string_view path) {
if (path.empty()) {
return {};
}
if (path == "/"sv) {
return "/"sv;
}
auto pos = path.rfind('/');
while (!path.empty() && pos == path.size() - 1) {
path.remove_suffix(1);
pos = path.rfind('/');
}
if (pos == path.npos) {
return path.empty() ? "/"sv : path;
}
return path.substr(pos + 1);
}
std::string_view dirname(std::string_view path) {
if (path.empty()) {
return {};
}
if (path == "/"sv) {
return "/"sv;
}
const auto pos = path.rfind('/');
if (pos == 0) {
return "/"sv;
}
if (pos == path.npos) {
return "."sv;
}
return path.substr(0, pos);
}
details::CStrWrapper::CStrWrapper(std::string_view sv) {
if (sv[sv.size()] == '\0') {
mCstr = sv.data();
} else {
mCopy.emplace(sv);
mCstr = mCopy->c_str();
}
}
std::optional<bool> isEmptyDir(std::string_view dir) {
const auto d = std::unique_ptr<DIR, decltype(&::closedir)>{::opendir(c_str(dir)), ::closedir};
if (!d) {
if (errno == EPERM || errno == EACCES) {
return std::nullopt;
}
return false;
}
while (auto entry = ::readdir(d.get())) {
if (entry->d_type != DT_DIR) {
return false;
}
if (entry->d_name != "."sv && entry->d_name != ".."sv) {
return false;
}
}
return true;
}
bool startsWith(std::string_view path, std::string_view prefix) {
if (!base::StartsWith(path, prefix)) {
return false;
}
return path.size() == prefix.size() || path[prefix.size()] == '/';
}
} // namespace android::incremental::path
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