michael@0: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "base/file_util.h"
michael@0: 
michael@0: #include <windows.h>
michael@0: #include <psapi.h>
michael@0: #include <shellapi.h>
michael@0: #include <shlobj.h>
michael@0: #include <time.h>
michael@0: 
michael@0: #include <algorithm>
michael@0: #include <limits>
michael@0: #include <string>
michael@0: 
michael@0: #include "base/files/file_path.h"
michael@0: #include "base/logging.h"
michael@0: #include "base/metrics/histogram.h"
michael@0: #include "base/process/process_handle.h"
michael@0: #include "base/rand_util.h"
michael@0: #include "base/strings/string_number_conversions.h"
michael@0: #include "base/strings/string_util.h"
michael@0: #include "base/strings/utf_string_conversions.h"
michael@0: #include "base/threading/thread_restrictions.h"
michael@0: #include "base/time/time.h"
michael@0: #include "base/win/scoped_handle.h"
michael@0: #include "base/win/windows_version.h"
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: const DWORD kFileShareAll =
michael@0:     FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
michael@0: 
michael@0: bool ShellCopy(const FilePath& from_path,
michael@0:                const FilePath& to_path,
michael@0:                bool recursive) {
michael@0:   // WinXP SHFileOperation doesn't like trailing separators.
michael@0:   FilePath stripped_from = from_path.StripTrailingSeparators();
michael@0:   FilePath stripped_to = to_path.StripTrailingSeparators();
michael@0: 
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   // NOTE: I suspect we could support longer paths, but that would involve
michael@0:   // analyzing all our usage of files.
michael@0:   if (stripped_from.value().length() >= MAX_PATH ||
michael@0:       stripped_to.value().length() >= MAX_PATH) {
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
michael@0:   // so we have to use wcscpy because wcscpy_s writes non-NULLs
michael@0:   // into the rest of the buffer.
michael@0:   wchar_t double_terminated_path_from[MAX_PATH + 1] = {0};
michael@0:   wchar_t double_terminated_path_to[MAX_PATH + 1] = {0};
michael@0: #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
michael@0:   wcscpy(double_terminated_path_from, stripped_from.value().c_str());
michael@0: #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
michael@0:   wcscpy(double_terminated_path_to, stripped_to.value().c_str());
michael@0: 
michael@0:   SHFILEOPSTRUCT file_operation = {0};
michael@0:   file_operation.wFunc = FO_COPY;
michael@0:   file_operation.pFrom = double_terminated_path_from;
michael@0:   file_operation.pTo = double_terminated_path_to;
michael@0:   file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION |
michael@0:                           FOF_NOCONFIRMMKDIR;
michael@0:   if (!recursive)
michael@0:     file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
michael@0: 
michael@0:   return (SHFileOperation(&file_operation) == 0);
michael@0: }
michael@0: 
michael@0: }  // namespace
michael@0: 
michael@0: FilePath MakeAbsoluteFilePath(const FilePath& input) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0:   wchar_t file_path[MAX_PATH];
michael@0:   if (!_wfullpath(file_path, input.value().c_str(), MAX_PATH))
michael@0:     return FilePath();
michael@0:   return FilePath(file_path);
michael@0: }
michael@0: 
michael@0: bool DeleteFile(const FilePath& path, bool recursive) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   if (path.value().length() >= MAX_PATH)
michael@0:     return false;
michael@0: 
michael@0:   if (!recursive) {
michael@0:     // If not recursing, then first check to see if |path| is a directory.
michael@0:     // If it is, then remove it with RemoveDirectory.
michael@0:     PlatformFileInfo file_info;
michael@0:     if (file_util::GetFileInfo(path, &file_info) && file_info.is_directory)
michael@0:       return RemoveDirectory(path.value().c_str()) != 0;
michael@0: 
michael@0:     // Otherwise, it's a file, wildcard or non-existant. Try DeleteFile first
michael@0:     // because it should be faster. If DeleteFile fails, then we fall through
michael@0:     // to SHFileOperation, which will do the right thing.
michael@0:     if (::DeleteFile(path.value().c_str()) != 0)
michael@0:       return true;
michael@0:   }
michael@0: 
michael@0:   // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
michael@0:   // so we have to use wcscpy because wcscpy_s writes non-NULLs
michael@0:   // into the rest of the buffer.
michael@0:   wchar_t double_terminated_path[MAX_PATH + 1] = {0};
michael@0: #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
michael@0:   if (g_bug108724_debug)
michael@0:     LOG(WARNING) << "copying ";
michael@0:   wcscpy(double_terminated_path, path.value().c_str());
michael@0: 
michael@0:   SHFILEOPSTRUCT file_operation = {0};
michael@0:   file_operation.wFunc = FO_DELETE;
michael@0:   file_operation.pFrom = double_terminated_path;
michael@0:   file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION;
michael@0:   if (!recursive)
michael@0:     file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
michael@0:   if (g_bug108724_debug)
michael@0:     LOG(WARNING) << "Performing shell operation";
michael@0:   int err = SHFileOperation(&file_operation);
michael@0:   if (g_bug108724_debug)
michael@0:     LOG(WARNING) << "Done: " << err;
michael@0: 
michael@0:   // Since we're passing flags to the operation telling it to be silent,
michael@0:   // it's possible for the operation to be aborted/cancelled without err
michael@0:   // being set (although MSDN doesn't give any scenarios for how this can
michael@0:   // happen).  See MSDN for SHFileOperation and SHFILEOPTSTRUCT.
michael@0:   if (file_operation.fAnyOperationsAborted)
michael@0:     return false;
michael@0: 
michael@0:   // Some versions of Windows return ERROR_FILE_NOT_FOUND (0x2) when deleting
michael@0:   // an empty directory and some return 0x402 when they should be returning
michael@0:   // ERROR_FILE_NOT_FOUND. MSDN says Vista and up won't return 0x402.
michael@0:   return (err == 0 || err == ERROR_FILE_NOT_FOUND || err == 0x402);
michael@0: }
michael@0: 
michael@0: bool DeleteFileAfterReboot(const FilePath& path) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   if (path.value().length() >= MAX_PATH)
michael@0:     return false;
michael@0: 
michael@0:   return MoveFileEx(path.value().c_str(), NULL,
michael@0:                     MOVEFILE_DELAY_UNTIL_REBOOT |
michael@0:                         MOVEFILE_REPLACE_EXISTING) != FALSE;
michael@0: }
michael@0: 
michael@0: bool ReplaceFile(const FilePath& from_path,
michael@0:                  const FilePath& to_path,
michael@0:                  PlatformFileError* error) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0:   // Try a simple move first.  It will only succeed when |to_path| doesn't
michael@0:   // already exist.
michael@0:   if (::MoveFile(from_path.value().c_str(), to_path.value().c_str()))
michael@0:     return true;
michael@0:   // Try the full-blown replace if the move fails, as ReplaceFile will only
michael@0:   // succeed when |to_path| does exist. When writing to a network share, we may
michael@0:   // not be able to change the ACLs. Ignore ACL errors then
michael@0:   // (REPLACEFILE_IGNORE_MERGE_ERRORS).
michael@0:   if (::ReplaceFile(to_path.value().c_str(), from_path.value().c_str(), NULL,
michael@0:                     REPLACEFILE_IGNORE_MERGE_ERRORS, NULL, NULL)) {
michael@0:     return true;
michael@0:   }
michael@0:   if (error)
michael@0:     *error = LastErrorToPlatformFileError(GetLastError());
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: bool CopyDirectory(const FilePath& from_path, const FilePath& to_path,
michael@0:                    bool recursive) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   if (recursive)
michael@0:     return ShellCopy(from_path, to_path, true);
michael@0: 
michael@0:   // The following code assumes that from path is a directory.
michael@0:   DCHECK(DirectoryExists(from_path));
michael@0: 
michael@0:   // Instead of creating a new directory, we copy the old one to include the
michael@0:   // security information of the folder as part of the copy.
michael@0:   if (!PathExists(to_path)) {
michael@0:     // Except that Vista fails to do that, and instead do a recursive copy if
michael@0:     // the target directory doesn't exist.
michael@0:     if (base::win::GetVersion() >= base::win::VERSION_VISTA)
michael@0:       file_util::CreateDirectory(to_path);
michael@0:     else
michael@0:       ShellCopy(from_path, to_path, false);
michael@0:   }
michael@0: 
michael@0:   FilePath directory = from_path.Append(L"*.*");
michael@0:   return ShellCopy(directory, to_path, false);
michael@0: }
michael@0: 
michael@0: bool PathExists(const FilePath& path) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0:   return (GetFileAttributes(path.value().c_str()) != INVALID_FILE_ATTRIBUTES);
michael@0: }
michael@0: 
michael@0: bool PathIsWritable(const FilePath& path) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0:   HANDLE dir =
michael@0:       CreateFile(path.value().c_str(), FILE_ADD_FILE, kFileShareAll,
michael@0:                  NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
michael@0: 
michael@0:   if (dir == INVALID_HANDLE_VALUE)
michael@0:     return false;
michael@0: 
michael@0:   CloseHandle(dir);
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool DirectoryExists(const FilePath& path) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0:   DWORD fileattr = GetFileAttributes(path.value().c_str());
michael@0:   if (fileattr != INVALID_FILE_ATTRIBUTES)
michael@0:     return (fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0;
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: }  // namespace base
michael@0: 
michael@0: // -----------------------------------------------------------------------------
michael@0: 
michael@0: namespace file_util {
michael@0: 
michael@0: using base::DirectoryExists;
michael@0: using base::FilePath;
michael@0: using base::kFileShareAll;
michael@0: 
michael@0: bool GetTempDir(FilePath* path) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   wchar_t temp_path[MAX_PATH + 1];
michael@0:   DWORD path_len = ::GetTempPath(MAX_PATH, temp_path);
michael@0:   if (path_len >= MAX_PATH || path_len <= 0)
michael@0:     return false;
michael@0:   // TODO(evanm): the old behavior of this function was to always strip the
michael@0:   // trailing slash.  We duplicate this here, but it shouldn't be necessary
michael@0:   // when everyone is using the appropriate FilePath APIs.
michael@0:   *path = FilePath(temp_path).StripTrailingSeparators();
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool GetShmemTempDir(FilePath* path, bool executable) {
michael@0:   return GetTempDir(path);
michael@0: }
michael@0: 
michael@0: bool CreateTemporaryFile(FilePath* path) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   FilePath temp_file;
michael@0: 
michael@0:   if (!GetTempDir(path))
michael@0:     return false;
michael@0: 
michael@0:   if (CreateTemporaryFileInDir(*path, &temp_file)) {
michael@0:     *path = temp_file;
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: FILE* CreateAndOpenTemporaryShmemFile(FilePath* path, bool executable) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   return CreateAndOpenTemporaryFile(path);
michael@0: }
michael@0: 
michael@0: // On POSIX we have semantics to create and open a temporary file
michael@0: // atomically.
michael@0: // TODO(jrg): is there equivalent call to use on Windows instead of
michael@0: // going 2-step?
michael@0: FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   if (!CreateTemporaryFileInDir(dir, path)) {
michael@0:     return NULL;
michael@0:   }
michael@0:   // Open file in binary mode, to avoid problems with fwrite. On Windows
michael@0:   // it replaces \n's with \r\n's, which may surprise you.
michael@0:   // Reference: http://msdn.microsoft.com/en-us/library/h9t88zwz(VS.71).aspx
michael@0:   return OpenFile(*path, "wb+");
michael@0: }
michael@0: 
michael@0: bool CreateTemporaryFileInDir(const FilePath& dir,
michael@0:                               FilePath* temp_file) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   wchar_t temp_name[MAX_PATH + 1];
michael@0: 
michael@0:   if (!GetTempFileName(dir.value().c_str(), L"", 0, temp_name)) {
michael@0:     DPLOG(WARNING) << "Failed to get temporary file name in " << dir.value();
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   wchar_t long_temp_name[MAX_PATH + 1];
michael@0:   DWORD long_name_len = GetLongPathName(temp_name, long_temp_name, MAX_PATH);
michael@0:   if (long_name_len > MAX_PATH || long_name_len == 0) {
michael@0:     // GetLongPathName() failed, but we still have a temporary file.
michael@0:     *temp_file = FilePath(temp_name);
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   FilePath::StringType long_temp_name_str;
michael@0:   long_temp_name_str.assign(long_temp_name, long_name_len);
michael@0:   *temp_file = FilePath(long_temp_name_str);
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool CreateTemporaryDirInDir(const FilePath& base_dir,
michael@0:                              const FilePath::StringType& prefix,
michael@0:                              FilePath* new_dir) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   FilePath path_to_create;
michael@0: 
michael@0:   for (int count = 0; count < 50; ++count) {
michael@0:     // Try create a new temporary directory with random generated name. If
michael@0:     // the one exists, keep trying another path name until we reach some limit.
michael@0:     string16 new_dir_name;
michael@0:     new_dir_name.assign(prefix);
michael@0:     new_dir_name.append(base::IntToString16(::base::GetCurrentProcId()));
michael@0:     new_dir_name.push_back('_');
michael@0:     new_dir_name.append(base::IntToString16(base::RandInt(0, kint16max)));
michael@0: 
michael@0:     path_to_create = base_dir.Append(new_dir_name);
michael@0:     if (::CreateDirectory(path_to_create.value().c_str(), NULL)) {
michael@0:       *new_dir = path_to_create;
michael@0:       return true;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: bool CreateNewTempDirectory(const FilePath::StringType& prefix,
michael@0:                             FilePath* new_temp_path) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   FilePath system_temp_dir;
michael@0:   if (!GetTempDir(&system_temp_dir))
michael@0:     return false;
michael@0: 
michael@0:   return CreateTemporaryDirInDir(system_temp_dir, prefix, new_temp_path);
michael@0: }
michael@0: 
michael@0: bool CreateDirectoryAndGetError(const FilePath& full_path,
michael@0:                                 base::PlatformFileError* error) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   // If the path exists, we've succeeded if it's a directory, failed otherwise.
michael@0:   const wchar_t* full_path_str = full_path.value().c_str();
michael@0:   DWORD fileattr = ::GetFileAttributes(full_path_str);
michael@0:   if (fileattr != INVALID_FILE_ATTRIBUTES) {
michael@0:     if ((fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0) {
michael@0:       DVLOG(1) << "CreateDirectory(" << full_path_str << "), "
michael@0:                << "directory already exists.";
michael@0:       return true;
michael@0:     }
michael@0:     DLOG(WARNING) << "CreateDirectory(" << full_path_str << "), "
michael@0:                   << "conflicts with existing file.";
michael@0:     if (error) {
michael@0:       *error = base::PLATFORM_FILE_ERROR_NOT_A_DIRECTORY;
michael@0:     }
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   // Invariant:  Path does not exist as file or directory.
michael@0: 
michael@0:   // Attempt to create the parent recursively.  This will immediately return
michael@0:   // true if it already exists, otherwise will create all required parent
michael@0:   // directories starting with the highest-level missing parent.
michael@0:   FilePath parent_path(full_path.DirName());
michael@0:   if (parent_path.value() == full_path.value()) {
michael@0:     if (error) {
michael@0:       *error = base::PLATFORM_FILE_ERROR_NOT_FOUND;
michael@0:     }
michael@0:     return false;
michael@0:   }
michael@0:   if (!CreateDirectoryAndGetError(parent_path, error)) {
michael@0:     DLOG(WARNING) << "Failed to create one of the parent directories.";
michael@0:     if (error) {
michael@0:       DCHECK(*error != base::PLATFORM_FILE_OK);
michael@0:     }
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   if (!::CreateDirectory(full_path_str, NULL)) {
michael@0:     DWORD error_code = ::GetLastError();
michael@0:     if (error_code == ERROR_ALREADY_EXISTS && DirectoryExists(full_path)) {
michael@0:       // This error code ERROR_ALREADY_EXISTS doesn't indicate whether we
michael@0:       // were racing with someone creating the same directory, or a file
michael@0:       // with the same path.  If DirectoryExists() returns true, we lost the
michael@0:       // race to create the same directory.
michael@0:       return true;
michael@0:     } else {
michael@0:       if (error)
michael@0:         *error = base::LastErrorToPlatformFileError(error_code);
michael@0:       DLOG(WARNING) << "Failed to create directory " << full_path_str
michael@0:                     << ", last error is " << error_code << ".";
michael@0:       return false;
michael@0:     }
michael@0:   } else {
michael@0:     return true;
michael@0:   }
michael@0: }
michael@0: 
michael@0: // TODO(rkc): Work out if we want to handle NTFS junctions here or not, handle
michael@0: // them if we do decide to.
michael@0: bool IsLink(const FilePath& file_path) {
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: bool GetFileInfo(const FilePath& file_path, base::PlatformFileInfo* results) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   WIN32_FILE_ATTRIBUTE_DATA attr;
michael@0:   if (!GetFileAttributesEx(file_path.value().c_str(),
michael@0:                            GetFileExInfoStandard, &attr)) {
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   ULARGE_INTEGER size;
michael@0:   size.HighPart = attr.nFileSizeHigh;
michael@0:   size.LowPart = attr.nFileSizeLow;
michael@0:   results->size = size.QuadPart;
michael@0: 
michael@0:   results->is_directory =
michael@0:       (attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
michael@0:   results->last_modified = base::Time::FromFileTime(attr.ftLastWriteTime);
michael@0:   results->last_accessed = base::Time::FromFileTime(attr.ftLastAccessTime);
michael@0:   results->creation_time = base::Time::FromFileTime(attr.ftCreationTime);
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: FILE* OpenFile(const FilePath& filename, const char* mode) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   std::wstring w_mode = ASCIIToWide(std::string(mode));
michael@0:   return _wfsopen(filename.value().c_str(), w_mode.c_str(), _SH_DENYNO);
michael@0: }
michael@0: 
michael@0: FILE* OpenFile(const std::string& filename, const char* mode) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   return _fsopen(filename.c_str(), mode, _SH_DENYNO);
michael@0: }
michael@0: 
michael@0: int ReadFile(const FilePath& filename, char* data, int size) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
michael@0:                                           GENERIC_READ,
michael@0:                                           FILE_SHARE_READ | FILE_SHARE_WRITE,
michael@0:                                           NULL,
michael@0:                                           OPEN_EXISTING,
michael@0:                                           FILE_FLAG_SEQUENTIAL_SCAN,
michael@0:                                           NULL));
michael@0:   if (!file)
michael@0:     return -1;
michael@0: 
michael@0:   DWORD read;
michael@0:   if (::ReadFile(file, data, size, &read, NULL) &&
michael@0:       static_cast<int>(read) == size)
michael@0:     return read;
michael@0:   return -1;
michael@0: }
michael@0: 
michael@0: int WriteFile(const FilePath& filename, const char* data, int size) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
michael@0:                                           GENERIC_WRITE,
michael@0:                                           0,
michael@0:                                           NULL,
michael@0:                                           CREATE_ALWAYS,
michael@0:                                           0,
michael@0:                                           NULL));
michael@0:   if (!file) {
michael@0:     DLOG_GETLASTERROR(WARNING) << "CreateFile failed for path "
michael@0:                                << filename.value();
michael@0:     return -1;
michael@0:   }
michael@0: 
michael@0:   DWORD written;
michael@0:   BOOL result = ::WriteFile(file, data, size, &written, NULL);
michael@0:   if (result && static_cast<int>(written) == size)
michael@0:     return written;
michael@0: 
michael@0:   if (!result) {
michael@0:     // WriteFile failed.
michael@0:     DLOG_GETLASTERROR(WARNING) << "writing file " << filename.value()
michael@0:                                << " failed";
michael@0:   } else {
michael@0:     // Didn't write all the bytes.
michael@0:     DLOG(WARNING) << "wrote" << written << " bytes to "
michael@0:                   << filename.value() << " expected " << size;
michael@0:   }
michael@0:   return -1;
michael@0: }
michael@0: 
michael@0: int AppendToFile(const FilePath& filename, const char* data, int size) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
michael@0:                                           FILE_APPEND_DATA,
michael@0:                                           0,
michael@0:                                           NULL,
michael@0:                                           OPEN_EXISTING,
michael@0:                                           0,
michael@0:                                           NULL));
michael@0:   if (!file) {
michael@0:     DLOG_GETLASTERROR(WARNING) << "CreateFile failed for path "
michael@0:                                << filename.value();
michael@0:     return -1;
michael@0:   }
michael@0: 
michael@0:   DWORD written;
michael@0:   BOOL result = ::WriteFile(file, data, size, &written, NULL);
michael@0:   if (result && static_cast<int>(written) == size)
michael@0:     return written;
michael@0: 
michael@0:   if (!result) {
michael@0:     // WriteFile failed.
michael@0:     DLOG_GETLASTERROR(WARNING) << "writing file " << filename.value()
michael@0:                                << " failed";
michael@0:   } else {
michael@0:     // Didn't write all the bytes.
michael@0:     DLOG(WARNING) << "wrote" << written << " bytes to "
michael@0:                   << filename.value() << " expected " << size;
michael@0:   }
michael@0:   return -1;
michael@0: }
michael@0: 
michael@0: // Gets the current working directory for the process.
michael@0: bool GetCurrentDirectory(FilePath* dir) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   wchar_t system_buffer[MAX_PATH];
michael@0:   system_buffer[0] = 0;
michael@0:   DWORD len = ::GetCurrentDirectory(MAX_PATH, system_buffer);
michael@0:   if (len == 0 || len > MAX_PATH)
michael@0:     return false;
michael@0:   // TODO(evanm): the old behavior of this function was to always strip the
michael@0:   // trailing slash.  We duplicate this here, but it shouldn't be necessary
michael@0:   // when everyone is using the appropriate FilePath APIs.
michael@0:   std::wstring dir_str(system_buffer);
michael@0:   *dir = FilePath(dir_str).StripTrailingSeparators();
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: // Sets the current working directory for the process.
michael@0: bool SetCurrentDirectory(const FilePath& directory) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   BOOL ret = ::SetCurrentDirectory(directory.value().c_str());
michael@0:   return ret != 0;
michael@0: }
michael@0: 
michael@0: bool NormalizeFilePath(const FilePath& path, FilePath* real_path) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   FilePath mapped_file;
michael@0:   if (!NormalizeToNativeFilePath(path, &mapped_file))
michael@0:     return false;
michael@0:   // NormalizeToNativeFilePath() will return a path that starts with
michael@0:   // "\Device\Harddisk...".  Helper DevicePathToDriveLetterPath()
michael@0:   // will find a drive letter which maps to the path's device, so
michael@0:   // that we return a path starting with a drive letter.
michael@0:   return DevicePathToDriveLetterPath(mapped_file, real_path);
michael@0: }
michael@0: 
michael@0: bool DevicePathToDriveLetterPath(const FilePath& nt_device_path,
michael@0:                                  FilePath* out_drive_letter_path) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   // Get the mapping of drive letters to device paths.
michael@0:   const int kDriveMappingSize = 1024;
michael@0:   wchar_t drive_mapping[kDriveMappingSize] = {'\0'};
michael@0:   if (!::GetLogicalDriveStrings(kDriveMappingSize - 1, drive_mapping)) {
michael@0:     DLOG(ERROR) << "Failed to get drive mapping.";
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   // The drive mapping is a sequence of null terminated strings.
michael@0:   // The last string is empty.
michael@0:   wchar_t* drive_map_ptr = drive_mapping;
michael@0:   wchar_t device_path_as_string[MAX_PATH];
michael@0:   wchar_t drive[] = L" :";
michael@0: 
michael@0:   // For each string in the drive mapping, get the junction that links
michael@0:   // to it.  If that junction is a prefix of |device_path|, then we
michael@0:   // know that |drive| is the real path prefix.
michael@0:   while (*drive_map_ptr) {
michael@0:     drive[0] = drive_map_ptr[0];  // Copy the drive letter.
michael@0: 
michael@0:     if (QueryDosDevice(drive, device_path_as_string, MAX_PATH)) {
michael@0:       FilePath device_path(device_path_as_string);
michael@0:       if (device_path == nt_device_path ||
michael@0:           device_path.IsParent(nt_device_path)) {
michael@0:         *out_drive_letter_path = FilePath(drive +
michael@0:             nt_device_path.value().substr(wcslen(device_path_as_string)));
michael@0:         return true;
michael@0:       }
michael@0:     }
michael@0:     // Move to the next drive letter string, which starts one
michael@0:     // increment after the '\0' that terminates the current string.
michael@0:     while (*drive_map_ptr++);
michael@0:   }
michael@0: 
michael@0:   // No drive matched.  The path does not start with a device junction
michael@0:   // that is mounted as a drive letter.  This means there is no drive
michael@0:   // letter path to the volume that holds |device_path|, so fail.
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: bool NormalizeToNativeFilePath(const FilePath& path, FilePath* nt_path) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0:   // In Vista, GetFinalPathNameByHandle() would give us the real path
michael@0:   // from a file handle.  If we ever deprecate XP, consider changing the
michael@0:   // code below to a call to GetFinalPathNameByHandle().  The method this
michael@0:   // function uses is explained in the following msdn article:
michael@0:   // http://msdn.microsoft.com/en-us/library/aa366789(VS.85).aspx
michael@0:   base::win::ScopedHandle file_handle(
michael@0:       ::CreateFile(path.value().c_str(),
michael@0:                    GENERIC_READ,
michael@0:                    kFileShareAll,
michael@0:                    NULL,
michael@0:                    OPEN_EXISTING,
michael@0:                    FILE_ATTRIBUTE_NORMAL,
michael@0:                    NULL));
michael@0:   if (!file_handle)
michael@0:     return false;
michael@0: 
michael@0:   // Create a file mapping object.  Can't easily use MemoryMappedFile, because
michael@0:   // we only map the first byte, and need direct access to the handle. You can
michael@0:   // not map an empty file, this call fails in that case.
michael@0:   base::win::ScopedHandle file_map_handle(
michael@0:       ::CreateFileMapping(file_handle.Get(),
michael@0:                           NULL,
michael@0:                           PAGE_READONLY,
michael@0:                           0,
michael@0:                           1,  // Just one byte.  No need to look at the data.
michael@0:                           NULL));
michael@0:   if (!file_map_handle)
michael@0:     return false;
michael@0: 
michael@0:   // Use a view of the file to get the path to the file.
michael@0:   void* file_view = MapViewOfFile(file_map_handle.Get(),
michael@0:                                   FILE_MAP_READ, 0, 0, 1);
michael@0:   if (!file_view)
michael@0:     return false;
michael@0: 
michael@0:   // The expansion of |path| into a full path may make it longer.
michael@0:   // GetMappedFileName() will fail if the result is longer than MAX_PATH.
michael@0:   // Pad a bit to be safe.  If kMaxPathLength is ever changed to be less
michael@0:   // than MAX_PATH, it would be nessisary to test that GetMappedFileName()
michael@0:   // not return kMaxPathLength.  This would mean that only part of the
michael@0:   // path fit in |mapped_file_path|.
michael@0:   const int kMaxPathLength = MAX_PATH + 10;
michael@0:   wchar_t mapped_file_path[kMaxPathLength];
michael@0:   bool success = false;
michael@0:   HANDLE cp = GetCurrentProcess();
michael@0:   if (::GetMappedFileNameW(cp, file_view, mapped_file_path, kMaxPathLength)) {
michael@0:     *nt_path = FilePath(mapped_file_path);
michael@0:     success = true;
michael@0:   }
michael@0:   ::UnmapViewOfFile(file_view);
michael@0:   return success;
michael@0: }
michael@0: 
michael@0: int GetMaximumPathComponentLength(const FilePath& path) {
michael@0:   base::ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   wchar_t volume_path[MAX_PATH];
michael@0:   if (!GetVolumePathNameW(path.NormalizePathSeparators().value().c_str(),
michael@0:                           volume_path,
michael@0:                           arraysize(volume_path))) {
michael@0:     return -1;
michael@0:   }
michael@0: 
michael@0:   DWORD max_length = 0;
michael@0:   if (!GetVolumeInformationW(volume_path, NULL, 0, NULL, &max_length, NULL,
michael@0:                              NULL, 0)) {
michael@0:     return -1;
michael@0:   }
michael@0: 
michael@0:   // Length of |path| with path separator appended.
michael@0:   size_t prefix = path.StripTrailingSeparators().value().size() + 1;
michael@0:   // The whole path string must be shorter than MAX_PATH. That is, it must be
michael@0:   // prefix + component_length < MAX_PATH (or equivalently, <= MAX_PATH - 1).
michael@0:   int whole_path_limit = std::max(0, MAX_PATH - 1 - static_cast<int>(prefix));
michael@0:   return std::min(whole_path_limit, static_cast<int>(max_length));
michael@0: }
michael@0: 
michael@0: }  // namespace file_util
michael@0: 
michael@0: namespace base {
michael@0: namespace internal {
michael@0: 
michael@0: bool MoveUnsafe(const FilePath& from_path, const FilePath& to_path) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   // NOTE: I suspect we could support longer paths, but that would involve
michael@0:   // analyzing all our usage of files.
michael@0:   if (from_path.value().length() >= MAX_PATH ||
michael@0:       to_path.value().length() >= MAX_PATH) {
michael@0:     return false;
michael@0:   }
michael@0:   if (MoveFileEx(from_path.value().c_str(), to_path.value().c_str(),
michael@0:                  MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING) != 0)
michael@0:     return true;
michael@0: 
michael@0:   // Keep the last error value from MoveFileEx around in case the below
michael@0:   // fails.
michael@0:   bool ret = false;
michael@0:   DWORD last_error = ::GetLastError();
michael@0: 
michael@0:   if (DirectoryExists(from_path)) {
michael@0:     // MoveFileEx fails if moving directory across volumes. We will simulate
michael@0:     // the move by using Copy and Delete. Ideally we could check whether
michael@0:     // from_path and to_path are indeed in different volumes.
michael@0:     ret = internal::CopyAndDeleteDirectory(from_path, to_path);
michael@0:   }
michael@0: 
michael@0:   if (!ret) {
michael@0:     // Leave a clue about what went wrong so that it can be (at least) picked
michael@0:     // up by a PLOG entry.
michael@0:     ::SetLastError(last_error);
michael@0:   }
michael@0: 
michael@0:   return ret;
michael@0: }
michael@0: 
michael@0: bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0: 
michael@0:   // NOTE: I suspect we could support longer paths, but that would involve
michael@0:   // analyzing all our usage of files.
michael@0:   if (from_path.value().length() >= MAX_PATH ||
michael@0:       to_path.value().length() >= MAX_PATH) {
michael@0:     return false;
michael@0:   }
michael@0:   return (::CopyFile(from_path.value().c_str(), to_path.value().c_str(),
michael@0:                      false) != 0);
michael@0: }
michael@0: 
michael@0: bool CopyAndDeleteDirectory(const FilePath& from_path,
michael@0:                             const FilePath& to_path) {
michael@0:   ThreadRestrictions::AssertIOAllowed();
michael@0:   if (CopyDirectory(from_path, to_path, true)) {
michael@0:     if (DeleteFile(from_path, true))
michael@0:       return true;
michael@0: 
michael@0:     // Like Move, this function is not transactional, so we just
michael@0:     // leave the copied bits behind if deleting from_path fails.
michael@0:     // If to_path exists previously then we have already overwritten
michael@0:     // it by now, we don't get better off by deleting the new bits.
michael@0:   }
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: }  // namespace internal
michael@0: }  // namespace base