[llvm] r221841 - Improve long path name support on Windows.
Paul Robinson
paul_robinson at playstation.sony.com
Wed Nov 12 16:12:14 PST 2014
Author: probinson
Date: Wed Nov 12 18:12:14 2014
New Revision: 221841
URL: http://llvm.org/viewvc/llvm-project?rev=221841&view=rev
Log:
Improve long path name support on Windows.
Windows normally limits the length of an absolute path name to 260
characters; directories can have lower limits. These limits increase
to about 32K if you use absolute paths with the special '\\?\'
prefix. Teach Support\Windows\Path.inc to use that prefix as needed.
TODO: Other parts of Support could also learn to use this prefix.
Modified:
llvm/trunk/lib/Support/Windows/Path.inc
llvm/trunk/unittests/Support/Path.cpp
Modified: llvm/trunk/lib/Support/Windows/Path.inc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Windows/Path.inc?rev=221841&r1=221840&r2=221841&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Windows/Path.inc (original)
+++ llvm/trunk/lib/Support/Windows/Path.inc Wed Nov 12 18:12:14 2014
@@ -59,6 +59,59 @@ static bool is_separator(const wchar_t v
}
}
+// Convert a UTF-8 path to UTF-16. Also, if the absolute equivalent of the
+// path is longer than CreateDirectory can tolerate, make it absolute and
+// prefixed by '\\?\'.
+static std::error_code widenPath(const Twine &Path8,
+ SmallVectorImpl<wchar_t> &Path16) {
+ const size_t MaxDirLen = MAX_PATH - 12; // Must leave room for 8.3 filename.
+
+ // Several operations would convert Path8 to SmallString; more efficient to
+ // do it once up front.
+ SmallString<128> Path8Str;
+ Path8.toVector(Path8Str);
+
+ // If we made this path absolute, how much longer would it get?
+ size_t CurPathLen;
+ if (llvm::sys::path::is_absolute(Twine(Path8Str)))
+ CurPathLen = 0; // No contribution from current_path needed.
+ else {
+ CurPathLen = ::GetCurrentDirectoryW(0, NULL);
+ if (CurPathLen == 0)
+ return windows_error(::GetLastError());
+ }
+
+ // Would the absolute path be longer than our limit?
+ if ((Path8Str.size() + CurPathLen) >= MaxDirLen &&
+ !Path8Str.startswith("\\\\?\\")) {
+ SmallString<2*MAX_PATH> FullPath("\\\\?\\");
+ if (CurPathLen) {
+ SmallString<80> CurPath;
+ if (std::error_code EC = llvm::sys::fs::current_path(CurPath))
+ return EC;
+ FullPath.append(CurPath);
+ }
+ // Traverse the requested path, canonicalizing . and .. as we go (because
+ // the \\?\ prefix is documented to treat them as real components).
+ // The iterators don't report separators and append() always attaches
+ // preferred_separator so we don't need to call native() on the result.
+ for (llvm::sys::path::const_iterator I = llvm::sys::path::begin(Path8Str),
+ E = llvm::sys::path::end(Path8Str);
+ I != E; ++I) {
+ if (I->size() == 1 && *I == ".")
+ continue;
+ if (I->size() == 2 && *I == "..")
+ llvm::sys::path::remove_filename(FullPath);
+ else
+ llvm::sys::path::append(FullPath, *I);
+ }
+ return UTF8ToUTF16(FullPath, Path16);
+ }
+
+ // Just use the caller's original path.
+ return UTF8ToUTF16(Path8Str, Path16);
+}
+
namespace llvm {
namespace sys {
namespace fs {
@@ -130,11 +183,9 @@ std::error_code current_path(SmallVector
}
std::error_code create_directory(const Twine &path, bool IgnoreExisting) {
- SmallString<128> path_storage;
SmallVector<wchar_t, 128> path_utf16;
- if (std::error_code ec =
- UTF8ToUTF16(path.toStringRef(path_storage), path_utf16))
+ if (std::error_code ec = widenPath(path, path_utf16))
return ec;
if (!::CreateDirectoryW(path_utf16.begin(), NULL)) {
@@ -148,18 +199,12 @@ std::error_code create_directory(const T
// We can't use symbolic links for windows.
std::error_code create_link(const Twine &to, const Twine &from) {
- // Get arguments.
- SmallString<128> from_storage;
- SmallString<128> to_storage;
- StringRef f = from.toStringRef(from_storage);
- StringRef t = to.toStringRef(to_storage);
-
// Convert to utf-16.
SmallVector<wchar_t, 128> wide_from;
SmallVector<wchar_t, 128> wide_to;
- if (std::error_code ec = UTF8ToUTF16(f, wide_from))
+ if (std::error_code ec = widenPath(from, wide_from))
return ec;
- if (std::error_code ec = UTF8ToUTF16(t, wide_to))
+ if (std::error_code ec = widenPath(to, wide_to))
return ec;
if (!::CreateHardLinkW(wide_from.begin(), wide_to.begin(), NULL))
@@ -169,7 +214,6 @@ std::error_code create_link(const Twine
}
std::error_code remove(const Twine &path, bool IgnoreNonExisting) {
- SmallString<128> path_storage;
SmallVector<wchar_t, 128> path_utf16;
file_status ST;
@@ -179,8 +223,7 @@ std::error_code remove(const Twine &path
return std::error_code();
}
- if (std::error_code ec =
- UTF8ToUTF16(path.toStringRef(path_storage), path_utf16))
+ if (std::error_code ec = widenPath(path, path_utf16))
return ec;
if (ST.type() == file_type::directory_file) {
@@ -200,18 +243,12 @@ std::error_code remove(const Twine &path
}
std::error_code rename(const Twine &from, const Twine &to) {
- // Get arguments.
- SmallString<128> from_storage;
- SmallString<128> to_storage;
- StringRef f = from.toStringRef(from_storage);
- StringRef t = to.toStringRef(to_storage);
-
// Convert to utf-16.
SmallVector<wchar_t, 128> wide_from;
SmallVector<wchar_t, 128> wide_to;
- if (std::error_code ec = UTF8ToUTF16(f, wide_from))
+ if (std::error_code ec = widenPath(from, wide_from))
return ec;
- if (std::error_code ec = UTF8ToUTF16(t, wide_to))
+ if (std::error_code ec = widenPath(to, wide_to))
return ec;
std::error_code ec = std::error_code();
@@ -232,11 +269,9 @@ std::error_code rename(const Twine &from
}
std::error_code resize_file(const Twine &path, uint64_t size) {
- SmallString<128> path_storage;
SmallVector<wchar_t, 128> path_utf16;
- if (std::error_code ec =
- UTF8ToUTF16(path.toStringRef(path_storage), path_utf16))
+ if (std::error_code ec = widenPath(path, path_utf16))
return ec;
int fd = ::_wopen(path_utf16.begin(), O_BINARY | _O_RDWR, S_IWRITE);
@@ -252,11 +287,9 @@ std::error_code resize_file(const Twine
}
std::error_code access(const Twine &Path, AccessMode Mode) {
- SmallString<128> PathStorage;
SmallVector<wchar_t, 128> PathUtf16;
- if (std::error_code EC =
- UTF8ToUTF16(Path.toStringRef(PathStorage), PathUtf16))
+ if (std::error_code EC = widenPath(Path, PathUtf16))
return EC;
DWORD Attributes = ::GetFileAttributesW(PathUtf16.begin());
@@ -382,7 +415,7 @@ std::error_code status(const Twine &path
return std::error_code();
}
- if (std::error_code ec = UTF8ToUTF16(path8, path_utf16))
+ if (std::error_code ec = widenPath(path8, path_utf16))
return ec;
DWORD attr = ::GetFileAttributesW(path_utf16.begin());
@@ -525,11 +558,10 @@ mapped_file_region::mapped_file_region(c
, FileDescriptor()
, FileHandle(INVALID_HANDLE_VALUE)
, FileMappingHandle() {
- SmallString<128> path_storage;
SmallVector<wchar_t, 128> path_utf16;
// Convert path to UTF-16.
- if ((ec = UTF8ToUTF16(path.toStringRef(path_storage), path_utf16)))
+ if (ec = widenPath(path, path_utf16))
return;
// Get file handle for creating a file mapping.
@@ -635,7 +667,7 @@ std::error_code detail::directory_iterat
StringRef path){
SmallVector<wchar_t, 128> path_utf16;
- if (std::error_code ec = UTF8ToUTF16(path, path_utf16))
+ if (std::error_code ec = widenPath(path, path_utf16))
return ec;
// Convert path to the format that Windows is happy with.
@@ -718,11 +750,9 @@ std::error_code detail::directory_iterat
}
std::error_code openFileForRead(const Twine &Name, int &ResultFD) {
- SmallString<128> PathStorage;
SmallVector<wchar_t, 128> PathUTF16;
- if (std::error_code EC =
- UTF8ToUTF16(Name.toStringRef(PathStorage), PathUTF16))
+ if (std::error_code EC = widenPath(Name, PathUTF16))
return EC;
HANDLE H = ::CreateFileW(PathUTF16.begin(), GENERIC_READ,
@@ -757,11 +787,9 @@ std::error_code openFileForWrite(const T
assert((!(Flags & sys::fs::F_Excl) || !(Flags & sys::fs::F_Append)) &&
"Cannot specify both 'excl' and 'append' file creation flags!");
- SmallString<128> PathStorage;
SmallVector<wchar_t, 128> PathUTF16;
- if (std::error_code EC =
- UTF8ToUTF16(Name.toStringRef(PathStorage), PathUTF16))
+ if (std::error_code EC = widenPath(Name, PathUTF16))
return EC;
DWORD CreationDisposition;
Modified: llvm/trunk/unittests/Support/Path.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/Path.cpp?rev=221841&r1=221840&r2=221841&view=diff
==============================================================================
--- llvm/trunk/unittests/Support/Path.cpp (original)
+++ llvm/trunk/unittests/Support/Path.cpp Wed Nov 12 18:12:14 2014
@@ -16,6 +16,7 @@
#include "gtest/gtest.h"
#ifdef LLVM_ON_WIN32
+#include <Windows.h>
#include <winerror.h>
#endif
@@ -261,7 +262,7 @@ TEST(Support, HomeDirectory) {
class FileSystemTest : public testing::Test {
protected:
/// Unique temporary directory in which all created filesystem entities must
- /// be placed. It is recursively removed at the end of each test.
+ /// be placed. It is removed at the end of each test (must be empty).
SmallString<128> TestDirectory;
virtual void SetUp() {
@@ -397,7 +398,15 @@ TEST_F(FileSystemTest, TempFiles) {
"abcdefghijklmnopqrstuvwxyz3abcdefghijklmnopqrstuvwxyz2"
"abcdefghijklmnopqrstuvwxyz1abcdefghijklmnopqrstuvwxyz0";
EXPECT_EQ(fs::createUniqueFile(Twine(Path270), FileDescriptor, TempPath),
- errc::no_such_file_or_directory);
+ errc::invalid_argument);
+ // Relative path < 247 chars, no problem.
+ const char *Path216 =
+ "abcdefghijklmnopqrstuvwxyz7abcdefghijklmnopqrstuvwxyz6"
+ "abcdefghijklmnopqrstuvwxyz5abcdefghijklmnopqrstuvwxyz4"
+ "abcdefghijklmnopqrstuvwxyz3abcdefghijklmnopqrstuvwxyz2"
+ "abcdefghijklmnopqrstuvwxyz1abcdefghijklmnopqrstuvwxyz0";
+ ASSERT_NO_ERROR(fs::createTemporaryFile(Twine(Path216), "", TempPath));
+ ASSERT_NO_ERROR(fs::remove(Twine(TempPath)));
#endif
}
@@ -407,6 +416,54 @@ TEST_F(FileSystemTest, CreateDir) {
ASSERT_EQ(fs::create_directory(Twine(TestDirectory) + "foo", false),
errc::file_exists);
ASSERT_NO_ERROR(fs::remove(Twine(TestDirectory) + "foo"));
+
+#ifdef LLVM_ON_WIN32
+ // Prove that create_directories() can handle a pathname > 248 characters,
+ // which is the documented limit for CreateDirectory().
+ // (248 is MAX_PATH subtracting room for an 8.3 filename.)
+ // Generate a directory path guaranteed to fall into that range.
+ size_t TmpLen = TestDirectory.size();
+ const char *OneDir = "\\123456789";
+ size_t OneDirLen = strlen(OneDir);
+ ASSERT_LT(OneDirLen, 12);
+ size_t NLevels = ((248 - TmpLen) / OneDirLen) + 1;
+ SmallString<260> LongDir(TestDirectory);
+ for (size_t I = 0; I < NLevels; ++I)
+ LongDir.append(OneDir);
+ ASSERT_NO_ERROR(fs::create_directories(Twine(LongDir)));
+ ASSERT_NO_ERROR(fs::create_directories(Twine(LongDir)));
+ ASSERT_EQ(fs::create_directories(Twine(LongDir), false),
+ errc::file_exists);
+ // Tidy up, "recursively" removing the directories.
+ StringRef ThisDir(LongDir);
+ for (size_t J = 0; J < NLevels; ++J) {
+ ASSERT_NO_ERROR(fs::remove(ThisDir));
+ ThisDir = path::parent_path(ThisDir);
+ }
+
+ // Similarly for a relative pathname. Need to set the current directory to
+ // TestDirectory so that the one we create ends up in the right place.
+ char PreviousDir[260];
+ size_t PreviousDirLen = ::GetCurrentDirectoryA(260, PreviousDir);
+ ASSERT_GT(PreviousDirLen, 0);
+ ASSERT_LT(PreviousDirLen, 260);
+ ASSERT_NE(::SetCurrentDirectoryA(TestDirectory.c_str()), 0);
+ LongDir.clear();
+ // Generate a relative directory name with absolute length > 248.
+ size_t LongDirLen = 249 - TestDirectory.size();
+ LongDir.assign(LongDirLen, 'a');
+ ASSERT_NO_ERROR(fs::create_directory(Twine(LongDir)));
+ // While we're here, prove that .. and . handling works in these long paths.
+ const char *DotDotDirs = "\\..\\.\\b";
+ LongDir.append(DotDotDirs);
+ ASSERT_NO_ERROR(fs::create_directory(Twine("b")));
+ ASSERT_EQ(fs::create_directory(Twine(LongDir), false), errc::file_exists);
+ // And clean up.
+ ASSERT_NO_ERROR(fs::remove(Twine("b")));
+ ASSERT_NO_ERROR(fs::remove(
+ Twine(LongDir.substr(0, LongDir.size() - strlen(DotDotDirs)))));
+ ASSERT_NE(::SetCurrentDirectoryA(PreviousDir), 0);
+#endif
}
TEST_F(FileSystemTest, DirectoryIteration) {
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