LocalStorage: new API abstracting filesystem walk

Prepare to make this a new plugin API, for example to use a SMB share
for the music_directory.

src/storage/FileInfo.hxx

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2003-2014 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.
+ */
+
+#ifndef MPD_STORAGE_FILE_INFO_HXX
+#define MPD_STORAGE_FILE_INFO_HXX
+
+#include "check.h"
+
+#include <time.h>
+#include <stdint.h>
+
+struct FileInfo {
+	enum class Type : uint8_t {
+		OTHER,
+		REGULAR,
+		DIRECTORY,
+	};
+
+	Type type;
+
+	/**
+	 * The file size in bytes.  Only valid for #Type::REGULAR.
+	 */
+	uint64_t size;
+
+	/**
+	 * The modification time.  0 means unknown / not applicable.
+	 */
+	time_t mtime;
+
+	/**
+	 * Device id and inode number.  0 means unknown / not
+	 * applicable.
+	 */
+	unsigned device, inode;
+
+	bool IsRegular() const {
+		return type == Type::REGULAR;
+	}
+
+	bool IsDirectory() const {
+		return type == Type::DIRECTORY;
+	}
+};
+
+#endif

src/storage/LocalStorage.cxx

@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2003-2014 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 "LocalStorage.hxx"
+#include "FileInfo.hxx"
+#include "util/Error.hxx"
+#include "fs/FileSystem.hxx"
+
+static bool
+Stat(Path path, bool follow, FileInfo &info, Error &error)
+{
+	struct stat st;
+	if (!StatFile(path, st, follow)) {
+		error.SetErrno();
+
+		const auto path_utf8 = path.ToUTF8();
+		error.FormatPrefix("Failed to stat %s: ", path_utf8.c_str());
+		return false;
+	}
+
+	if (S_ISREG(st.st_mode))
+		info.type = FileInfo::Type::REGULAR;
+	else if (S_ISDIR(st.st_mode))
+		info.type = FileInfo::Type::DIRECTORY;
+	else
+		info.type = FileInfo::Type::OTHER;
+
+	info.size = st.st_size;
+	info.mtime = st.st_mtime;
+	info.device = st.st_dev;
+	info.inode = st.st_ino;
+	return true;
+}
+
+std::string
+LocalStorage::MapUTF8(const char *uri_utf8) const
+{
+	assert(uri_utf8 != nullptr);
+
+	if (*uri_utf8 == 0)
+		return base_utf8;
+
+	return PathTraitsUTF8::Build(base_utf8.c_str(), uri_utf8);
+}
+
+AllocatedPath
+LocalStorage::MapFS(const char *uri_utf8, Error &error) const
+{
+	assert(uri_utf8 != nullptr);
+
+	if (*uri_utf8 == 0)
+		return base_fs;
+
+	AllocatedPath path_fs = AllocatedPath::FromUTF8(uri_utf8, error);
+	if (!path_fs.IsNull())
+		path_fs = AllocatedPath::Build(base_fs, path_fs);
+
+	return path_fs;
+}
+
+AllocatedPath
+LocalStorage::MapFS(const char *uri_utf8) const
+{
+	return MapFS(uri_utf8, IgnoreError());
+}
+
+AllocatedPath
+LocalStorage::MapChildFS(const char *uri_utf8,
+			 const char *child_utf8) const
+{
+	const auto uri2 = PathTraitsUTF8::Build(uri_utf8, child_utf8);
+	return MapFS(uri2.c_str());
+}
+
+bool
+LocalStorage::GetInfo(const char *uri_utf8, bool follow, FileInfo &info,
+		      Error &error)
+{
+	AllocatedPath path_fs = MapFS(uri_utf8, error);
+	if (path_fs.IsNull())
+		return false;
+
+	return Stat(path_fs, follow, info, error);
+}
+
+LocalDirectoryReader *
+LocalStorage::OpenDirectory(const char *uri_utf8, Error &error)
+{
+	AllocatedPath path_fs = MapFS(uri_utf8, error);
+	if (path_fs.IsNull())
+		return nullptr;
+
+	LocalDirectoryReader *reader =
+		new LocalDirectoryReader(std::move(path_fs));
+	if (reader->HasFailed()) {
+		error.FormatErrno("Failed to open '%s'", uri_utf8);
+		delete reader;
+		return nullptr;
+	}
+
+	return reader;
+}
+
+gcc_pure
+static bool
+SkipNameFS(const char *name_fs)
+{
+	return name_fs[0] == '.' &&
+		(name_fs[1] == 0 ||
+		 (name_fs[1] == '.' && name_fs[2] == 0));
+}
+
+const char *
+LocalDirectoryReader::Read()
+{
+	while (reader.ReadEntry()) {
+		const Path name_fs = reader.GetEntry();
+		if (SkipNameFS(name_fs.c_str()))
+			continue;
+
+		name_utf8 = name_fs.ToUTF8();
+		if (name_utf8.empty())
+			continue;
+
+		return name_utf8.c_str();
+	}
+
+	return nullptr;
+}
+
+bool
+LocalDirectoryReader::GetInfo(bool follow, FileInfo &info, Error &error)
+{
+	const AllocatedPath path_fs =
+		AllocatedPath::Build(base_fs, reader.GetEntry());
+	return Stat(path_fs, follow, info, error);
+}

src/storage/LocalStorage.hxx

@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2003-2014 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.
+ */
+
+#ifndef MPD_STORAGE_LOCAL_HXX
+#define MPD_STORAGE_LOCAL_HXX
+
+#include "check.h"
+#include "fs/AllocatedPath.hxx"
+#include "fs/DirectoryReader.hxx"
+
+#include <string>
+
+struct FileInfo;
+
+class LocalDirectoryReader {
+	AllocatedPath base_fs;
+
+	DirectoryReader reader;
+
+	std::string name_utf8;
+
+public:
+	LocalDirectoryReader(AllocatedPath &&_base_fs)
+		:base_fs(std::move(_base_fs)), reader(base_fs) {}
+
+	bool HasFailed() {
+		return reader.HasFailed();
+	}
+
+	const char *Read();
+
+	bool GetInfo(bool follow, FileInfo &info, Error &error);
+};
+
+class LocalStorage {
+	const std::string base_utf8;
+	const AllocatedPath base_fs;
+
+public:
+	LocalStorage(const char *_base_utf8, Path _base_fs)
+		:base_utf8(_base_utf8), base_fs(_base_fs) {}
+
+	LocalStorage(const LocalStorage &) = delete;
+
+	bool GetInfo(const char *uri_utf8, bool follow, FileInfo &info,
+		     Error &error);
+
+	LocalDirectoryReader *OpenDirectory(const char *uri_utf8,
+					    Error &error);
+
+	/**
+	 * Map the given relative URI to an absolute URI.
+	 */
+	gcc_pure
+	std::string MapUTF8(const char *uri_utf8) const;
+
+	/**
+	 * Map the given relative URI to a local file path.  Returns
+	 * AllocatedPath::Null() on error or if this storage does not
+	 * support local files.
+	 */
+	gcc_pure
+	AllocatedPath MapFS(const char *uri_utf8) const;
+
+	gcc_pure
+	AllocatedPath MapChildFS(const char *uri_utf8,
+				 const char *child_utf8) const;
+
+private:
+	AllocatedPath MapFS(const char *uri_utf8, Error &error) const;
+};
+
+#endif