LocateUri: new library to classify URIs in a standard way

1 files changed, 120 insertions, 0 deletions

diff --git a/src/LocateUri.cxx b/src/LocateUri.cxx
new file mode 100644
index 000000000..71c8d9093
--- /dev/null
+++ b/src/LocateUri.cxx
@@ -0,0 +1,120 @@
+/*
+ * 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 "LocateUri.hxx"
+#include "client/Client.hxx"
+#include "fs/AllocatedPath.hxx"
+#include "ls.hxx"
+#include "util/UriUtil.hxx"
+#include "util/StringUtil.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+
+#ifdef ENABLE_DATABASE
+#include "storage/StorageInterface.hxx"
+#endif
+
+const Domain locate_uri_domain("locate_uri");
+
+static LocatedUri
+LocateFileUri(const char *uri, const Client *client,
+#ifdef ENABLE_DATABASE
+	      const Storage *storage,
+#endif
+	      Error &error)
+{
+	auto path = AllocatedPath::FromUTF8(uri, error);
+	if (path.IsNull())
+		return LocatedUri::Unknown();
+
+#ifdef ENABLE_DATABASE
+	if (storage != nullptr) {
+		const char *suffix = storage->MapToRelativeUTF8(uri);
+		if (suffix != nullptr)
+			/* this path was relative to the music
+			   directory */
+			return LocatedUri(LocatedUri::Type::RELATIVE, suffix);
+	}
+#endif
+
+	if (client != nullptr && !client->AllowFile(path, error))
+		return LocatedUri::Unknown();
+
+	return LocatedUri(LocatedUri::Type::PATH, uri, std::move(path));
+}
+
+static LocatedUri
+LocateAbsoluteUri(const char *uri,
+#ifdef ENABLE_DATABASE
+		  const Storage *storage,
+#endif
+		  Error &error)
+{
+	if (!uri_supported_scheme(uri)) {
+		error.Set(locate_uri_domain, "Unsupported URI scheme");
+		return LocatedUri::Unknown();
+	}
+
+#ifdef ENABLE_DATABASE
+	if (storage != nullptr) {
+		const char *suffix = storage->MapToRelativeUTF8(uri);
+		if (suffix != nullptr)
+			return LocatedUri(LocatedUri::Type::RELATIVE, suffix);
+	}
+#endif
+
+	return LocatedUri(LocatedUri::Type::ABSOLUTE, uri);
+}
+
+LocatedUri
+LocateUri(const char *uri, const Client *client,
+#ifdef ENABLE_DATABASE
+	  const Storage *storage,
+#endif
+	  Error &error)
+{
+	/* skip the obsolete "file://" prefix */
+	const char *path_utf8 = StringAfterPrefix(uri, "file://");
+	if (path_utf8 != nullptr) {
+		if (!PathTraitsUTF8::IsAbsolute(path_utf8)) {
+			error.Set(locate_uri_domain, "Malformed file:// URI");
+			return LocatedUri::Unknown();
+		}
+
+		return LocateFileUri(path_utf8, client,
+#ifdef ENABLE_DATABASE
+				     storage,
+#endif
+				     error);
+	} else if (PathTraitsUTF8::IsAbsolute(uri))
+		return LocateFileUri(uri, client,
+#ifdef ENABLE_DATABASE
+				     storage,
+#endif
+				     error);
+	else if (uri_has_scheme(uri))
+		return LocateAbsoluteUri(uri,
+#ifdef ENABLE_DATABASE
+					 storage,
+#endif
+					 error);
+	else
+		return LocatedUri(LocatedUri::Type::RELATIVE, uri);
+}