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// Copyright 2016 The Bazel Authors. All rights reserved.
//
// 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 <stdio.h>
#include <stdlib.h>
#include <windows.h>
#include <algorithm>
#include <functional>
#include <memory>
#include <string>
#include "src/main/native/windows/util.h"
namespace bazel {
namespace windows {
using std::function;
using std::string;
using std::unique_ptr;
using std::wstring;
string GetLastErrorString(const string& cause) {
DWORD last_error = GetLastError();
if (last_error == 0) {
return "";
}
LPSTR message;
DWORD size = FormatMessageA(
FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, last_error, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPSTR)&message, 0, NULL);
if (size == 0) {
char buf[256];
snprintf(buf, sizeof(buf),
"%s: Error %d (cannot format message due to error %d)",
cause.c_str(), last_error, GetLastError());
buf[sizeof(buf) - 1] = 0;
}
string result = string(message);
LocalFree(message);
return cause + ": " + result;
}
static void QuotePath(const string& path, string* result) {
*result = string("\"") + path + "\"";
}
static bool IsSeparator(char c) { return c == '/' || c == '\\'; }
static bool HasSeparator(const string& s) {
return s.find_first_of('/') != string::npos ||
s.find_first_of('\\') != string::npos;
}
static bool Contains(const string& s, const char* substr) {
return s.find(substr) != string::npos;
}
string AsShortPath(string path, function<wstring()> path_as_wstring,
string* result) {
if (path.empty()) {
result->clear();
return "";
}
if (path[0] == '"') {
return string("path should not be quoted");
}
if (IsSeparator(path[0])) {
return string("path='") + path + "' is absolute";
}
if (Contains(path, "/./") || Contains(path, "\\.\\") ||
Contains(path, "/..") || Contains(path, "\\..")) {
return string("path='") + path + "' is not normalized";
}
if (path.size() >= MAX_PATH && !HasSeparator(path)) {
return string("path='") + path + "' is just a file name but too long";
}
if (HasSeparator(path) &&
!(isalpha(path[0]) && path[1] == ':' && IsSeparator(path[2]))) {
return string("path='") + path + "' is not an absolute path";
}
// At this point we know the path is either just a file name (shorter than
// MAX_PATH), or an absolute, normalized, Windows-style path (of any length).
std::replace(path.begin(), path.end(), '/', '\\');
// Fast-track: the path is already short.
if (path.size() < MAX_PATH) {
*result = path;
return "";
}
// At this point we know that the path is at least MAX_PATH long and that it's
// absolute, normalized, and Windows-style.
// Retrieve string as UTF-16 path, add "\\?\" prefix.
wstring wlong = wstring(L"\\\\?\\") + path_as_wstring();
// Experience shows that:
// - GetShortPathNameW's result has a "\\?\" prefix if and only if the input
// did too (though this behavior is not documented on MSDN)
// - CreateProcess{A,W} only accept an executable of MAX_PATH - 1 length
// Therefore for our purposes the acceptable shortened length is
// MAX_PATH + 4 (null-terminated). That is, MAX_PATH - 1 for the shortened
// path, plus a potential "\\?\" prefix that's only there if `wlong` also had
// it and which we'll omit from `result`, plus a null terminator.
static const size_t kMaxShortPath = MAX_PATH + 4;
WCHAR wshort[kMaxShortPath];
DWORD wshort_size = ::GetShortPathNameW(wlong.c_str(), NULL, 0);
if (wshort_size == 0) {
return GetLastErrorString(string("GetShortPathName failed (path=") + path +
")");
}
if (wshort_size >= kMaxShortPath) {
return string("GetShortPathName would not shorten the path enough (path=") +
path + ")";
}
GetShortPathNameW(wlong.c_str(), wshort, kMaxShortPath);
// Convert the result to UTF-8.
char mbs_short[MAX_PATH];
size_t mbs_size = wcstombs(
mbs_short,
wshort + 4, // we know it has a "\\?\" prefix, because `wlong` also did
MAX_PATH);
if (mbs_size < 0 || mbs_size >= MAX_PATH) {
return string("wcstombs failed (path=") + path + ")";
}
mbs_short[mbs_size] = 0;
*result = mbs_short;
return "";
}
string AsExecutablePathForCreateProcess(const string& path,
function<wstring()> path_as_wstring,
string* result) {
if (path.empty()) {
return string("path should not be empty");
}
string error = AsShortPath(path, path_as_wstring, result);
if (error.empty()) {
// Quote the path in case it's something like "c:\foo\app name.exe".
// Do this unconditionally, there's no harm in quoting. Quotes are not
// allowed inside paths so we don't need to escape quotes.
QuotePath(*result, result);
}
return error;
}
} // namespace windows
} // namespace bazel
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