llvm/lib/Support/PathV2.cpp
2010-11-30 23:28:07 +00:00

517 lines
14 KiB
C++

//===-- PathV2.cpp - Implement OS Path Concept ------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the operating system PathV2 API.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/PathV2.h"
#include "llvm/Support/ErrorHandling.h"
#include <cctype>
namespace {
using llvm::StringRef;
bool is_separator(const char value) {
switch(value) {
#ifdef LLVM_ON_WIN32
case '\\': // fall through
#endif
case '/': return true;
default: return false;
}
}
#ifdef LLVM_ON_WIN32
const StringRef separators = "\\/";
const char prefered_separator = '\\';
#else
const StringRef separators = "/";
const char prefered_separator = '/';
#endif
StringRef find_first_component(const StringRef &path) {
// Look for this first component in the following order.
// * empty (in this case we return an empty string)
// * either C: or {//,\\}net.
// * {/,\}
// * {.,..}
// * {file,directory}name
if (path.empty())
return path;
// C:
if (path.size() >= 2 && std::isalpha(path[0]) && path[1] == ':')
return StringRef(path.begin(), 2);
// //net
if ((path.size() > 2) &&
(path.startswith("\\\\") || path.startswith("//")) &&
(path[2] != '\\' && path[2] != '/')) {
// Find the next directory separator.
size_t end = path.find_first_of("\\/", 2);
if (end == StringRef::npos)
return path;
else
return StringRef(path.begin(), end);
}
// {/,\}
if (path[0] == '\\' || path[0] == '/')
return StringRef(path.begin(), 1);
if (path.startswith(".."))
return StringRef(path.begin(), 2);
if (path[0] == '.')
return StringRef(path.begin(), 1);
// * {file,directory}name
size_t end = path.find_first_of("\\/", 2);
if (end == StringRef::npos)
return path;
else
return StringRef(path.begin(), end);
return StringRef();
}
size_t filename_pos(const StringRef &str) {
if (str.size() == 2 &&
is_separator(str[0]) &&
is_separator(str[1]))
return 0;
if (str.size() > 0 && is_separator(str[str.size() - 1]))
return str.size() - 1;
size_t pos = str.find_last_of(separators, str.size() - 1);
#ifdef LLVM_ON_WIN32
if (pos == StringRef::npos)
pos = str.find_last_of(':', str.size() - 2);
#endif
if (pos == StringRef::npos ||
(pos == 1 && is_separator(str[0])))
return 0;
return pos + 1;
}
size_t root_dir_start(const StringRef &str) {
// case "c:/"
#ifdef LLVM_ON_WIN32
if (str.size() > 2 &&
str[1] == ':' &&
is_separator(str[2]))
return 2;
#endif
// case "//"
if (str.size() == 2 &&
is_separator(str[0]) &&
str[0] == str[1])
return StringRef::npos;
// case "//net"
if (str.size() > 3 &&
is_separator(str[0]) &&
str[0] == str[1] &&
!is_separator(str[2])) {
return str.find_first_of(separators, 2);
}
// case "/"
if (str.size() > 0 && is_separator(str[0]))
return 0;
return StringRef::npos;
}
size_t parent_path_end(const StringRef &path) {
size_t end_pos = filename_pos(path);
bool filename_was_sep = path.size() > 0 && is_separator(path[end_pos]);
// Skip separators except for root dir.
size_t root_dir_pos = root_dir_start(StringRef(path.begin(), end_pos));
while(end_pos > 0 &&
(end_pos - 1) != root_dir_pos &&
is_separator(path[end_pos - 1]))
--end_pos;
if (end_pos == 1 && root_dir_pos == 0 && filename_was_sep)
return StringRef::npos;
return end_pos;
}
}
namespace llvm {
namespace sys {
namespace path {
const_iterator begin(const StringRef &path) {
const_iterator i;
i.Path = path;
i.Component = find_first_component(path);
i.Position = 0;
return i;
}
const_iterator end(const StringRef &path) {
const_iterator i;
i.Path = path;
i.Position = path.size();
return i;
}
const_iterator &const_iterator::operator++() {
assert(Position < Path.size() && "Tried to increment past end!");
// Increment Position to past the current component
Position += Component.size();
// Check for end.
if (Position == Path.size()) {
Component = StringRef();
return *this;
}
// Both POSIX and Windows treat paths that begin with exactly two separators
// specially.
bool was_net = Component.size() > 2 &&
is_separator(Component[0]) &&
Component[1] == Component[0] &&
!is_separator(Component[2]);
// Handle separators.
if (is_separator(Path[Position])) {
// Root dir.
if (was_net
#ifdef LLVM_ON_WIN32
// c:/
|| Component.endswith(":")
#endif
) {
Component = StringRef(Path.begin() + Position, 1);
return *this;
}
// Skip extra separators.
while (Position != Path.size() &&
is_separator(Path[Position])) {
++Position;
}
// Treat trailing '/' as a '.'.
if (Position == Path.size()) {
--Position;
Component = ".";
return *this;
}
}
// Find next component.
size_t end_pos = Path.find_first_of(separators, Position);
if (end_pos == StringRef::npos)
end_pos = Path.size();
Component = StringRef(Path.begin() + Position, end_pos - Position);
return *this;
}
const_iterator &const_iterator::operator--() {
// If we're at the end and the previous char was a '/', return '.'.
if (Position == Path.size() &&
Path.size() > 1 &&
is_separator(Path[Position - 1])
#ifdef LLVM_ON_WIN32
&& Path[Position - 2] != ':'
#endif
) {
--Position;
Component = ".";
return *this;
}
// Skip separators unless it's the root directory.
size_t root_dir_pos = root_dir_start(Path);
size_t end_pos = Position;
while(end_pos > 0 &&
(end_pos - 1) != root_dir_pos &&
is_separator(Path[end_pos - 1]))
--end_pos;
// Find next separator.
size_t start_pos = filename_pos(StringRef(Path.begin(), end_pos));
Component = StringRef(Path.begin() + start_pos, end_pos - start_pos);
Position = start_pos;
return *this;
}
bool const_iterator::operator==(const const_iterator &RHS) const {
return Path.begin() == RHS.Path.begin() &&
Position == RHS.Position;
}
bool const_iterator::operator!=(const const_iterator &RHS) const {
return !(*this == RHS);
}
ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
return Position - RHS.Position;
}
error_code root_path(const StringRef &path, StringRef &result) {
const_iterator b = begin(path),
pos = b,
e = end(path);
if (b != e) {
bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
bool has_drive =
#ifdef LLVM_ON_WIN32
b->endswith(":");
#else
false;
#endif
if (has_net || has_drive) {
if ((++pos != e) && is_separator((*pos)[0])) {
// {C:/,//net/}, so get the first two components.
result = StringRef(path.begin(), b->size() + pos->size());
return make_error_code(errc::success);
} else {
// just {C:,//net}, return the first component.
result = *b;
return make_error_code(errc::success);
}
}
// POSIX style root directory.
if (is_separator((*b)[0])) {
result = *b;
return make_error_code(errc::success);
}
// No root_path.
result = StringRef();
return make_error_code(errc::success);
}
// No path :(.
result = StringRef();
return make_error_code(errc::success);
}
error_code root_name(const StringRef &path, StringRef &result) {
const_iterator b = begin(path),
e = end(path);
if (b != e) {
bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
bool has_drive =
#ifdef LLVM_ON_WIN32
b->endswith(":");
#else
false;
#endif
if (has_net || has_drive) {
// just {C:,//net}, return the first component.
result = *b;
return make_error_code(errc::success);
}
}
// No path or no name.
result = StringRef();
return make_error_code(errc::success);
}
error_code root_directory(const StringRef &path, StringRef &result) {
const_iterator b = begin(path),
pos = b,
e = end(path);
if (b != e) {
bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
bool has_drive =
#ifdef LLVM_ON_WIN32
b->endswith(":");
#else
false;
#endif
if ((has_net || has_drive) &&
// {C:,//net}, skip to the next component.
(++pos != e) && is_separator((*pos)[0])) {
result = *pos;
return make_error_code(errc::success);
}
// POSIX style root directory.
if (!has_net && is_separator((*b)[0])) {
result = *b;
return make_error_code(errc::success);
}
}
// No path or no root.
result = StringRef();
return make_error_code(errc::success);
}
error_code has_root_name(const Twine &path, bool &result) {
SmallString<128> storage;
StringRef p = path.toStringRef(storage);
if (error_code ec = root_name(p, p)) return ec;
result = !p.empty();
return make_error_code(errc::success);
}
error_code has_root_directory(const Twine &path, bool &result) {
SmallString<128> storage;
StringRef p = path.toStringRef(storage);
if (error_code ec = root_directory(p, p)) return ec;
result = !p.empty();
return make_error_code(errc::success);
}
error_code relative_path(const StringRef &path, StringRef &result) {
StringRef root;
if (error_code ec = root_path(path, root)) return ec;
result = StringRef(path.begin() + root.size(), path.size() - root.size());
return make_error_code(errc::success);
}
error_code append(SmallVectorImpl<char> &path, const Twine &a,
const Twine &b,
const Twine &c,
const Twine &d) {
SmallString<32> a_storage;
SmallString<32> b_storage;
SmallString<32> c_storage;
SmallString<32> d_storage;
SmallVector<StringRef, 4> components;
if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
for (SmallVectorImpl<StringRef>::const_iterator i = components.begin(),
e = components.end();
i != e; ++i) {
bool path_has_sep = !path.empty() && is_separator(path[path.size() - 1]);
bool component_has_sep = !i->empty() && is_separator((*i)[0]);
bool is_root_name;
if (error_code ec = has_root_name(*i, is_root_name)) return ec;
if (path_has_sep) {
// Strip separators from beginning of component.
size_t loc = i->find_first_not_of(separators);
StringRef c = StringRef(i->begin() + loc, i->size() - loc);
// Append it.
path.append(c.begin(), c.end());
continue;
}
if (!component_has_sep && !(path.empty() && is_root_name)) {
// Add a separator.
path.push_back(prefered_separator);
}
path.append(i->begin(), i->end());
}
return make_error_code(errc::success);
}
error_code make_absolute(SmallVectorImpl<char> &path) {
StringRef p(path.data(), path.size());
bool rootName, rootDirectory;
if (error_code ec = has_root_name(p, rootName)) return ec;
if (error_code ec = has_root_directory(p, rootDirectory)) return ec;
// Already absolute.
if (rootName && rootDirectory)
return make_error_code(errc::success);
// All of the following conditions will need the current directory.
SmallString<128> current_dir;
if (error_code ec = current_path(current_dir)) return ec;
// Relative path. Prepend the current directory.
if (!rootName && !rootDirectory) {
// Append path to the current directory.
if (error_code ec = append(current_dir, p)) return ec;
// Set path to the result.
path.swap(current_dir);
return make_error_code(errc::success);
}
if (!rootName && rootDirectory) {
StringRef cdrn;
if (error_code ec = root_name(current_dir, cdrn)) return ec;
SmallString<128> curDirRootName(cdrn.begin(), cdrn.end());
if (error_code ec = append(curDirRootName, p)) return ec;
// Set path to the result.
path.swap(curDirRootName);
return make_error_code(errc::success);
}
if (rootName && !rootDirectory) {
StringRef pRootName;
StringRef bRootDirectory;
StringRef bRelativePath;
StringRef pRelativePath;
if (error_code ec = root_name(p, pRootName)) return ec;
if (error_code ec = root_directory(current_dir, bRootDirectory)) return ec;
if (error_code ec = relative_path(current_dir, bRelativePath)) return ec;
if (error_code ec = relative_path(p, pRelativePath)) return ec;
SmallString<128> res;
if (error_code ec = append(res, pRootName, bRootDirectory,
bRelativePath, pRelativePath)) return ec;
path.swap(res);
return make_error_code(errc::success);
}
llvm_unreachable("All rootName and rootDirectory combinations should have "
"occurred above!");
}
error_code parent_path(const StringRef &path, StringRef &result) {
size_t end_pos = parent_path_end(path);
if (end_pos == StringRef::npos)
result = StringRef();
else
result = StringRef(path.data(), end_pos);
return make_error_code(errc::success);
}
}
}
}
// Include the truly platform-specific parts.
#if defined(LLVM_ON_UNIX)
#include "Unix/PathV2.inc"
#endif
#if defined(LLVM_ON_WIN32)
#include "Windows/PathV2.inc"
#endif