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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, Max Wipfli <max.wipfli@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/LexicalPath.h>
#include <AK/StringBuilder.h>
#include <AK/StringView.h>
#include <AK/Vector.h>
namespace AK {
char s_single_dot = '.';
LexicalPath::LexicalPath(DeprecatedString path)
: m_string(canonicalized_path(move(path)))
{
if (m_string.is_empty()) {
m_string = ".";
m_dirname = m_string;
m_basename = {};
m_title = {};
m_extension = {};
m_parts.clear();
return;
}
m_parts = m_string.split_view('/');
auto last_slash_index = m_string.view().find_last('/');
if (!last_slash_index.has_value()) {
// The path contains a single part and is not absolute. m_dirname = "."sv
m_dirname = { &s_single_dot, 1 };
} else if (*last_slash_index == 0) {
// The path contains a single part and is absolute. m_dirname = "/"sv
m_dirname = m_string.substring_view(0, 1);
} else {
m_dirname = m_string.substring_view(0, *last_slash_index);
}
if (m_string == "/")
m_basename = m_string;
else {
VERIFY(m_parts.size() > 0);
m_basename = m_parts.last();
}
auto last_dot_index = m_basename.find_last('.');
// NOTE: if the dot index is 0, this means we have ".foo", it's not an extension, as the title would then be "".
if (last_dot_index.has_value() && *last_dot_index != 0) {
m_title = m_basename.substring_view(0, *last_dot_index);
m_extension = m_basename.substring_view(*last_dot_index + 1);
} else {
m_title = m_basename;
m_extension = {};
}
}
Vector<DeprecatedString> LexicalPath::parts() const
{
Vector<DeprecatedString> vector;
vector.ensure_capacity(m_parts.size());
for (auto& part : m_parts)
vector.unchecked_append(part);
return vector;
}
bool LexicalPath::has_extension(StringView extension) const
{
return m_string.ends_with(extension, CaseSensitivity::CaseInsensitive);
}
bool LexicalPath::is_child_of(LexicalPath const& possible_parent) const
{
// Any relative path is a child of an absolute path.
if (!this->is_absolute() && possible_parent.is_absolute())
return true;
// An absolute path can't meaningfully be a child of a relative path.
if (this->is_absolute() && !possible_parent.is_absolute())
return false;
// Two relative paths and two absolute paths can be meaningfully compared.
if (possible_parent.parts_view().size() > this->parts_view().size())
return false;
auto common_parts_with_parent = this->parts_view().span().trim(possible_parent.parts_view().size());
return common_parts_with_parent == possible_parent.parts_view().span();
}
DeprecatedString LexicalPath::canonicalized_path(DeprecatedString path)
{
if (path.is_null())
return {};
// NOTE: We never allow an empty m_string, if it's empty, we just set it to '.'.
if (path.is_empty())
return ".";
// NOTE: If there are no dots, no '//' and the path doesn't end with a slash, it is already canonical.
if (!path.contains("."sv) && !path.contains("//"sv) && !path.ends_with('/'))
return path;
auto is_absolute = path[0] == '/';
auto parts = path.split_view('/');
size_t approximate_canonical_length = 0;
Vector<DeprecatedString> canonical_parts;
for (auto& part : parts) {
if (part == ".")
continue;
if (part == "..") {
if (canonical_parts.is_empty()) {
if (is_absolute) {
// At the root, .. does nothing.
continue;
}
} else {
if (canonical_parts.last() != "..") {
// A .. and a previous non-.. part cancel each other.
canonical_parts.take_last();
continue;
}
}
}
approximate_canonical_length += part.length() + 1;
canonical_parts.append(part);
}
if (canonical_parts.is_empty() && !is_absolute)
canonical_parts.append(".");
StringBuilder builder(approximate_canonical_length);
if (is_absolute)
builder.append('/');
builder.join('/', canonical_parts);
return builder.to_deprecated_string();
}
DeprecatedString LexicalPath::absolute_path(DeprecatedString dir_path, DeprecatedString target)
{
if (LexicalPath(target).is_absolute()) {
return LexicalPath::canonicalized_path(target);
}
return LexicalPath::canonicalized_path(join(dir_path, target).string());
}
DeprecatedString LexicalPath::relative_path(StringView a_path, StringView a_prefix)
{
if (!a_path.starts_with('/') || !a_prefix.starts_with('/')) {
// FIXME: This should probably VERIFY or return an Optional<DeprecatedString>.
return ""sv;
}
if (a_path == a_prefix)
return ".";
// NOTE: Strip optional trailing slashes, except if the full path is only "/".
auto path = canonicalized_path(a_path);
auto prefix = canonicalized_path(a_prefix);
if (path == prefix)
return ".";
// NOTE: Handle this special case first.
if (prefix == "/"sv)
return path.substring_view(1);
// NOTE: This means the prefix is a direct child of the path.
if (path.starts_with(prefix) && path[prefix.length()] == '/') {
return path.substring_view(prefix.length() + 1);
}
auto path_parts = path.split_view('/');
auto prefix_parts = prefix.split_view('/');
size_t index_of_first_part_that_differs = 0;
for (; index_of_first_part_that_differs < path_parts.size() && index_of_first_part_that_differs < prefix_parts.size(); index_of_first_part_that_differs++) {
if (path_parts[index_of_first_part_that_differs] != prefix_parts[index_of_first_part_that_differs])
break;
}
StringBuilder builder;
for (size_t part_index = index_of_first_part_that_differs; part_index < prefix_parts.size(); part_index++) {
builder.append("../"sv);
}
for (size_t part_index = index_of_first_part_that_differs; part_index < path_parts.size(); part_index++) {
builder.append(path_parts[part_index]);
if (part_index != path_parts.size() - 1) // We don't need a slash after the file name or the name of the last directory
builder.append('/');
}
return builder.to_deprecated_string();
}
LexicalPath LexicalPath::append(StringView value) const
{
return LexicalPath::join(m_string, value);
}
LexicalPath LexicalPath::prepend(StringView value) const
{
return LexicalPath::join(value, m_string);
}
LexicalPath LexicalPath::parent() const
{
return append(".."sv);
}
}
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