fs/DirectoryReader: use C++ exceptions instead of class Error

src/fs/CheckFile.cxx

@@ -25,6 +25,7 @@
 #include "Path.hxx"
 #include "AllocatedPath.hxx"
 #include "DirectoryReader.hxx"
+#include "system/Error.hxx"
 
 #include <errno.h>
 #include <sys/stat.h>
@@ -58,11 +59,12 @@ CheckDirectoryReadable(Path path_fs)
 	}
 #endif
 
-	const DirectoryReader reader(path_fs);
-	if (reader.HasFailed() && errno == EACCES) {
-		const auto path_utf8 = path_fs.ToUTF8();
-		FormatError(config_domain,
-			    "No permission to read directory: %s",
-			    path_utf8.c_str());
+	try {
+		const DirectoryReader reader(path_fs);
+	} catch (const std::system_error &e) {
+		if (IsAccessDenied(e))
+			FormatError(config_domain,
+				    "No permission to read directory: %s",
+				    path_fs.ToUTF8().c_str());
 	}
 }

src/fs/DirectoryReader.cxx

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "DirectoryReader.hxx"
+#include "system/Error.hxx"
+
+#ifdef WIN32
+
+DirectoryReader::DirectoryReader(Path dir)
+	:handle(FindFirstFile(MakeWildcardPath(dir.c_str()), &data))
+{
+	if (handle == INVALID_HANDLE_VALUE)
+		throw FormatLastError("Failed to open %s", dir.c_str());
+}
+
+#else
+
+DirectoryReader::DirectoryReader(Path dir)
+	:dirp(opendir(dir.c_str()))
+{
+	if (dirp == nullptr)
+		throw FormatErrno("Failed to open %s", dir.c_str());
+}
+
+#endif

src/fs/DirectoryReader.hxx

@@ -61,10 +61,10 @@ class DirectoryReader {
 public:
 	/**
 	 * Creates new directory reader for the specified #dir.
+	 *
+	 * Throws std::system_error on error.
 	 */
-	explicit DirectoryReader(Path dir)
-		:handle(FindFirstFile(MakeWildcardPath(dir.c_str()), &data)) {
-	}
+	explicit DirectoryReader(Path dir);
 
 	DirectoryReader(const DirectoryReader &other) = delete;
 	DirectoryReader &operator=(const DirectoryReader &other) = delete;
@@ -73,15 +73,7 @@ public:
 	 * Destroys this instance.
 	 */
 	~DirectoryReader() {
-		if (!HasFailed())
-			FindClose(handle);
-	}
-
-	/**
-	 * Checks if directory failed to open.
-	 */
-	bool HasFailed() const {
-		return handle == INVALID_HANDLE_VALUE;
+		FindClose(handle);
 	}
 
 	/**
@@ -118,10 +110,10 @@ class DirectoryReader {
 public:
 	/**
 	 * Creates new directory reader for the specified #dir.
+	 *
+	 * Throws std::system_error on error.
 	 */
-	explicit DirectoryReader(Path dir)
-		:dirp(opendir(dir.c_str())) {
-	}
+	explicit DirectoryReader(Path dir);
 
 	DirectoryReader(const DirectoryReader &other) = delete;
 	DirectoryReader &operator=(const DirectoryReader &other) = delete;
@@ -130,22 +122,13 @@ public:
 	 * Destroys this instance.
 	 */
 	~DirectoryReader() {
-		if (!HasFailed())
-			closedir(dirp);
-	}
-
-	/**
-	 * Checks if directory failed to open. 
-	 */
-	bool HasFailed() const {
-		return dirp == nullptr;
+		closedir(dirp);
 	}
 
 	/**
 	 * Checks if directory entry is available.
 	 */
 	bool HasEntry() const {
-		assert(!HasFailed());
 		return ent != nullptr;
 	}
 
@@ -153,7 +136,6 @@ public:
 	 * Reads next directory entry.
 	 */
 	bool ReadEntry() {
-		assert(!HasFailed());
 		ent = readdir(dirp);
 		return HasEntry();
 	}