archive/ArchiveLookup: replace output parameters with a struct

src/archive/ArchiveLookup.cxx

 /*
- * Copyright 2003-2018 The Music Player Daemon Project
+ * Copyright 2003-2019 The Music Player Daemon Project
  * http://www.musicpd.org
  *
  * This program is free software; you can redistribute it and/or modify
@@ -36,9 +36,8 @@ FindSlash(char *p, size_t i) noexcept
 	return nullptr;
 }
 
-bool
-archive_lookup(char *pathname, const char **archive,
-	       const char **inpath)
+ArchiveLookupResult
+archive_lookup(char *pathname)
 {
 	size_t idx = strlen(pathname);
 
@@ -51,19 +50,17 @@ archive_lookup(char *pathname, const char **archive,
 
 			//is something found ins original path (is not an archive)
 			if (slash == nullptr)
-				return false;
+				return {};
 
 			//its a file ?
 			if (file_info.IsRegular()) {
 				//so the upper should be file
-				*archive = pathname;
-				*inpath = slash + 1;
-				return true;
+				return {Path::FromFS(pathname), Path::FromFS(slash + 1)};
 			} else {
 				FormatError(archive_domain,
 					    "Not a regular file: %s",
 					    pathname);
-				return false;
+				return {};
 			}
 		} catch (const std::system_error &e) {
 			if (!IsPathNotFound(e))
@@ -76,7 +73,7 @@ archive_lookup(char *pathname, const char **archive,
 
 		slash = FindSlash(pathname, idx - 1);
 		if (slash == nullptr)
-			return false;
+			return {};
 
 		*slash = 0;
 		idx = slash - pathname;

src/archive/ArchiveLookup.hxx

 /*
- * Copyright 2003-2018 The Music Player Daemon Project
+ * Copyright 2003-2019 The Music Player Daemon Project
  * http://www.musicpd.org
  *
  * This program is free software; you can redistribute it and/or modify
@@ -20,6 +20,17 @@
 #ifndef MPD_ARCHIVE_LOOKUP_HXX
 #define MPD_ARCHIVE_LOOKUP_HXX
 
+#include "fs/Path.hxx"
+
+struct ArchiveLookupResult {
+	Path archive = nullptr;
+	Path inside = nullptr;
+
+	constexpr operator bool() const noexcept {
+		return !archive.IsNull();
+	}
+};
+
 /**
  *
  * archive_lookup is used to determine if part of pathname refers to an regular
@@ -38,9 +49,8 @@
  *
  * Throws on error.
  */
-bool
-archive_lookup(char *pathname, const char **archive,
-	       const char **inpath);
+ArchiveLookupResult
+archive_lookup(char *pathname);
 
 #endif
 

src/input/plugins/ArchiveInputPlugin.cxx

@@ -44,9 +44,10 @@ OpenArchiveInputStream(Path path, Mutex &mutex)
 	};
 
 	// archive_lookup will modify pname when true is returned
-	const char *archive, *filename;
+	ArchiveLookupResult l;
 	try {
-		if (!archive_lookup(pname, &archive, &filename)) {
+		l = archive_lookup(pname);
+		if (l.archive.IsNull()) {
 			FormatDebug(archive_domain,
 				    "not an archive, lookup %s failed", pname);
 			return nullptr;
@@ -57,7 +58,7 @@ OpenArchiveInputStream(Path path, Mutex &mutex)
 		return nullptr;
 	}
 
-	const char *suffix = Path::FromFS(archive).GetSuffix();
+	const char *suffix = l.archive.GetSuffix();
 	if (suffix == nullptr)
 		return nullptr;
 
@@ -65,10 +66,10 @@ OpenArchiveInputStream(Path path, Mutex &mutex)
 	arplug = archive_plugin_from_suffix(suffix);
 	if (!arplug) {
 		FormatWarning(archive_domain,
-			      "can't handle archive %s", archive);
+			      "can't handle archive %s", l.archive.c_str());
 		return nullptr;
 	}
 
-	return archive_file_open(arplug, Path::FromFS(archive))
-		->OpenStream(filename, mutex);
+	return archive_file_open(arplug, l.archive)
+		->OpenStream(l.inside.c_str(), mutex);
 }

test/test_archive.cxx

@@ -8,39 +8,37 @@
 
 TEST(ArchiveTest, Lookup)
 {
-	const char *archive, *inpath;
-
 	char *path = strdup("");
-	EXPECT_THROW(archive_lookup(path, &archive, &inpath),
-		     std::system_error);
+	EXPECT_THROW(archive_lookup(path), std::system_error);
 	free(path);
 
 	path = strdup(".");
-	EXPECT_FALSE(archive_lookup(path, &archive, &inpath));
+	EXPECT_FALSE(archive_lookup(path));
 	free(path);
 
 	path = strdup("config.h");
-	EXPECT_FALSE(archive_lookup(path, &archive, &inpath));
+	EXPECT_FALSE(archive_lookup(path));
 	free(path);
 
 	path = strdup("src/foo/bar");
-	EXPECT_THROW(archive_lookup(path, &archive, &inpath),
-		     std::system_error);
+	EXPECT_THROW(archive_lookup(path), std::system_error);
 	free(path);
 
 	fclose(fopen("dummy", "w"));
 
 	path = strdup("dummy/foo/bar");
-	EXPECT_TRUE(archive_lookup(path, &archive, &inpath));
-	EXPECT_EQ((const char *)path, archive);
-	EXPECT_STREQ(archive, "dummy");
-	EXPECT_STREQ(inpath, "foo/bar");
+	auto result = archive_lookup(path);
+	EXPECT_TRUE(result);
+	EXPECT_EQ((const char *)path, result.archive.c_str());
+	EXPECT_STREQ(result.archive.c_str(), "dummy");
+	EXPECT_STREQ(result.inside.c_str(), "foo/bar");
 	free(path);
 
 	path = strdup("config.h/foo/bar");
-	EXPECT_TRUE(archive_lookup(path, &archive, &inpath));
-	EXPECT_EQ((const char *)path, archive);
-	EXPECT_STREQ(archive, "config.h");
-	EXPECT_STREQ(inpath, "foo/bar");
+	result = archive_lookup(path);
+	EXPECT_TRUE(result);
+	EXPECT_EQ((const char *)path, result.archive.c_str());
+	EXPECT_STREQ(result.archive.c_str(), "config.h");
+	EXPECT_STREQ(result.inside.c_str(), "foo/bar");
 	free(path);
 }