Refactor: Replaced fileidentifier_t with FileId

FileId is a new C++ class which thinly wraps an MD5 hash (produced
with QCryptographicHash) into an object.

FileId instances can be built directly from file paths using the
static fromPath() method or constructed from a known Md5Hash.

FileId also implements an asText() method (and, operator String() )
which converts the hash to a textual, hexidecimal representation
and as implementor of LogEntry::Arg::Base - can written directly
to a Log.

The file system's management of file identifiers has been replaced
with an always-sorted QList of FileId instances.

doomsday/engine/portable/include/fileid.h

@@ -0,0 +1,134 @@
+/**
+ * @file fileid.h
+ *
+ * Implements a file identifier in terms of a MD5 hash of its absolute path.
+ *
+ * @ingroup types
+ *
+ * @author Copyright &copy; 2003-2012 Jaakko Keränen <jaakko.keranen@iki.fi>
+ * @author Copyright &copy; 2005-2012 Daniel Swanson <danij@dengine.net>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA</small>
+ */
+
+#ifndef LIBDENG_FILEID_H
+#define LIBDENG_FILEID_H
+
+#include "fs_util.h"
+#include <de/Log>
+#include <de/str.h>
+
+#include <QByteArray>
+#include <QCryptographicHash>
+#include <QString>
+
+namespace de {
+
+/**
+ * File identifier (an MD5 hash).
+ */
+class FileId : public LogEntry::Arg::Base
+{
+public:
+    typedef QByteArray Md5Hash;
+
+public:
+    explicit FileId(Md5Hash _md5) : md5_(_md5.left(16))
+    {}
+
+    FileId(FileId const& other)
+        : md5_(other.md5())
+    {}
+
+    FileId& operator = (FileId other)
+    {
+        swap(*this, other);
+        return *this;
+    }
+
+    /// @return @c true= this FileId is lexically less than @a other.
+    bool operator < (FileId const& other) const { return md5_ < other.md5_; }
+
+    /// @return @c true= this FileId is equal to @a other (identical hashes).
+    bool operator == (FileId const& other) const { return md5_ == other.md5_; }
+
+    /// @return @c true= this FileId is not equal @a other (differing hashes).
+    bool operator != (FileId const& other) const { return md5_ != other.md5_; }
+
+    friend void swap(FileId& first, FileId& second) // nothrow
+    {
+#ifdef DENG2_QT_4_8_OR_NEWER
+        first.md5_.swap(second.md5_);
+#else
+        using std::swap;
+        swap(first.md5_, second.md5_);
+#endif
+    }
+
+    /// Converts this FileId to a text string.
+    operator String () const { return asText(); }
+
+    /// Converts this FileId to a text string.
+    String asText() const
+    {
+        String txt;
+        txt.reserve(32);
+        for(int i = 0; i < 16; ++i)
+        {
+            txt += String("%1").arg(String::number((byte)md5_.at(i), 16), 2, '0');
+        }
+        return txt;
+    }
+
+    // Implements LogEntry::Arg::Base.
+    LogEntry::Arg::Type logEntryArgType() const { return LogEntry::Arg::STRING; }
+
+    /// @return Md5hash for this FileId.
+    Md5Hash const& md5() const { return md5_; }
+
+    /**
+     * Constructs a new FileId instance by hashing the absolute @a path.
+     * @param path  Path to be hashed.
+     * @return Newly construced FileId.
+     */
+    static FileId fromPath(char const* path)
+    {
+        return FileId(hash(path));
+    }
+
+    /**
+     * Calculate an MD5 identifier for the absolute @a path.
+     * @return MD5 hash of the path.
+     */
+    static Md5Hash hash(char const* path)
+    {
+        // First normalize the name.
+        AutoStr* absPath = Str_Set(AutoStr_NewStd(), path);
+        F_MakeAbsolute(absPath, absPath);
+        F_FixSlashes(absPath, absPath);
+#if defined(WIN32) || defined(MACOSX)
+        // This is a case insensitive operation.
+        strupr(Str_Text(absPath));
+#endif
+        return QCryptographicHash::hash(QByteArray(Str_Text(absPath)), QCryptographicHash::Md5);
+    }
+
+private:
+    Md5Hash md5_;
+};
+
+} // namespace de
+
+#endif /* LIBDENG_FILEID_H */

doomsday/engine/portable/include/fs_main.h

@@ -122,7 +122,7 @@ class FS
     /**
      * @return  @c true if a file exists at @a path which can be opened for reading.
      */
-    static bool access(char const* path);
+    static bool accessFile(char const* path);
 
     /**
      * @return  The time when the file was last modified, as seconds since