Speed up FileName operator==, such that working with child documents on

Windows and Solaris is again possible.


git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@29444 a592a061-630c-0410-9148-cb99ea01b6c8

src/support/FileName.cpp

@@ -921,49 +921,18 @@ docstring const FileName::relPath(string const & path) const
 }
 
 
-// Note: According to Qt, QFileInfo::operator== is undefined when
-// both files do not exist (Qt4.5 gives true for all non-existent
-// files, while Qt4.4 compares the filenames).
-// see:
-// http://www.qtsoftware.com/developer/task-tracker/
-//   index_html?id=248471&method=entry.
-bool operator==(FileName const & l, FileName const & r)
+bool operator==(FileName const & lhs, FileName const & rhs)
 {
-	// FIXME: In future use Qt.
-	// Qt 4.4: We need to solve this warning from Qt documentation:
-	// * Long and short file names that refer to the same file on Windows are
-	//   treated as if they referred to different files.
-	// This is supposed to be fixed for Qt5.
-	FileName const lhs(os::internal_path(l.absFilename()));
-	FileName const rhs(os::internal_path(r.absFilename()));
-
-	if (lhs.empty())
-		// QFileInfo::operator==() returns false if the two QFileInfo are empty.
-		return rhs.empty();
-
-	if (rhs.empty())
-		// Avoid unnecessary checks below.
-		return false;
-
-	lhs.d->refresh();
-	rhs.d->refresh();
-	
-	if (!lhs.d->fi.isSymLink() && !rhs.d->fi.isSymLink()) {
-		// Qt already checks if the filesystem is case sensitive or not.
-		// see note above why the extra check with fileName is needed.
-		return lhs.d->fi == rhs.d->fi
-			&& lhs.d->fi.fileName() == rhs.d->fi.fileName();
+	// Firstly, compare the filenames.
+	if (QString::compare(toqstr(lhs.absFilename()),
+			     toqstr(rhs.absFilename()),
+			     os::isFilesystemCaseSensitive() ?
+			     Qt::CaseSensitive : Qt::CaseInsensitive) == 0) {
+		return true;
 	}
 
-	// FIXME: When/if QFileInfo support symlink comparison, remove this code.
-	QFileInfo fi1(lhs.d->fi);
-	if (fi1.isSymLink())
-		fi1 = QFileInfo(fi1.symLinkTarget());
-	QFileInfo fi2(rhs.d->fi);
-	if (fi2.isSymLink())
-		fi2 = QFileInfo(fi2.symLinkTarget());
-	// see note above why the extra check with fileName is needed.
-	return fi1 == fi2 && fi1.fileName() == fi2.fileName();
+	// They don't match, so check whether they point to the same file.
+	return os::isSameFile(lhs.toFilesystemEncoding(), rhs.toFilesystemEncoding());
 }
 
 

src/support/os.h

@@ -112,6 +112,9 @@ bool canAutoOpenFile(std::string const & ext, auto_open_mode const mode = VIEW);
  */
 bool autoOpenFile(std::string const & filename, auto_open_mode const mode = VIEW);
 
+/// Check whether two filenames point to the same file.
+bool isSameFile(std::string const & fileone, std::string const & filetwo);
+
 } // namespace os
 } // namespace support
 } // namespace lyx

src/support/os_cygwin.cpp

@@ -6,6 +6,7 @@
  * \author Ruurd A. Reitsma
  * \author Claus Hentschel
  * \author Angus Leeming
+ * \author Enrico Forestieri
  *
  * Full author contact details are available in file CREDITS.
  *
@@ -26,8 +27,8 @@
 #include <shellapi.h>
 #include <shlwapi.h>
 #include <limits.h>
-
 #include <sys/cygwin.h>
+#include <sys/stat.h>
 
 using namespace std;
 
@@ -281,6 +282,21 @@ bool autoOpenFile(string const & filename, auto_open_mode const mode)
 		win_path.c_str(), NULL, NULL, 1)) > 32;
 }
 
+
+bool isSameFile(string const & fileone, string const & filetwo)
+{
+	struct stat st1;
+	struct stat st2;
+
+	if (::stat(fileone.c_str(), &st1) == 0
+	    && ::stat(filetwo.c_str(), &st2) == 0) {
+		return st1.st_ino == st2.st_ino && st1.st_dev == st2.st_dev;
+	}
+
+	// One or both files cannot be accessed.
+	return false;
+}
+
 } // namespace os
 } // namespace support
 } // namespace lyx

src/support/os_unix.cpp

@@ -17,6 +17,8 @@
 #include "support/FileName.h"
 #include "support/lstrings.h"
 
+#include <sys/stat.h>
+
 #ifdef __APPLE__
 #include <Carbon/Carbon.h>
 #endif
@@ -215,6 +217,21 @@ bool autoOpenFile(string const & filename, auto_open_mode const mode)
 #endif
 }
 
+
+bool isSameFile(string const & fileone, string const & filetwo)
+{
+	struct stat st1;
+	struct stat st2;
+
+	if (::stat(fileone.c_str(), &st1) == 0
+	    && ::stat(filetwo.c_str(), &st2) == 0) {
+		return st1.st_ino == st2.st_ino && st1.st_dev == st2.st_dev;
+	}
+
+	// One or both files cannot be accessed.
+	return false;
+}
+
 } // namespace os
 } // namespace support
 } // namespace lyx

src/support/os_win32.cpp

@@ -389,6 +389,43 @@ bool autoOpenFile(string const & filename, auto_open_mode const mode)
 		to_local8bit(from_utf8(filename)).c_str(), NULL, NULL, 1)) > 32;
 }
 
+
+bool isSameFile(string const & fileone, string const & filetwo)
+{
+	HANDLE h1 = CreateFile(fileone.c_str(), 0,
+		FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
+	HANDLE h2 = CreateFile(filetwo.c_str(), 0,
+		FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
+
+	if (h1 == INVALID_HANDLE_VALUE || h2 == INVALID_HANDLE_VALUE) {
+		// One or both files cannot be accessed.
+		if (h1 != INVALID_HANDLE_VALUE)
+			CloseHandle(h1);
+		if (h2 != INVALID_HANDLE_VALUE)
+			CloseHandle(h2);
+		return false;
+	}
+
+	BY_HANDLE_FILE_INFORMATION info1;
+	BY_HANDLE_FILE_INFORMATION info2;
+	bool samefile = false;
+	if (GetFileInformationByHandle(h1, &info1) != 0
+	    && GetFileInformationByHandle(h2, &info2) != 0) {
+		// Serial number of the volumes containing the files.
+		ULONG st1_dev = info1.dwVolumeSerialNumber;
+		ULONG st2_dev = info2.dwVolumeSerialNumber;
+		// Unique identifiers associated to the files on the volumes.
+		ULONGLONG highbits = info1.nFileIndexHigh & 0x0000FFFF;
+		ULONGLONG st1_ino = (highbits << sizeof(ULONG)) | info1.nFileIndexLow;
+		highbits = info2.nFileIndexHigh & 0x0000FFFF;
+		ULONGLONG st2_ino = (highbits << sizeof(ULONG)) | info2.nFileIndexLow;
+		samefile = st1_ino == st2_ino && st1_dev == st2_dev;
+	}
+	CloseHandle(h1);
+	CloseHandle(h2);
+	return samefile;
+}
+
 } // namespace os
 } // namespace support
 } // namespace lyx