lib/smbclient/Context: new wrapper for SMBCCTX

src/input/plugins/SmbclientInputPlugin.cxx

@@ -19,6 +19,7 @@
 
 #include "SmbclientInputPlugin.hxx"
 #include "lib/smbclient/Init.hxx"
+#include "lib/smbclient/Context.hxx"
 #include "lib/smbclient/Mutex.hxx"
 #include "../InputStream.hxx"
 #include "../InputPlugin.hxx"
@@ -29,15 +30,17 @@
 #include <libsmbclient.h>
 
 class SmbclientInputStream final : public InputStream {
-	SMBCCTX *ctx;
+	SmbclientContext ctx;
 	int fd;
 
 public:
 	SmbclientInputStream(const char *_uri,
 			     Mutex &_mutex,
-			     SMBCCTX *_ctx, int _fd, const struct stat &st)
+			     SmbclientContext &&_ctx,
+			     int _fd, const struct stat &st)
 		:InputStream(_uri, _mutex),
-		 ctx(_ctx), fd(_fd) {
+		 ctx(std::move(_ctx)), fd(_fd)
+	{
 		seekable = true;
 		size = st.st_size;
 		SetReady();
@@ -46,7 +49,6 @@ public:
 	~SmbclientInputStream() override {
 		const std::lock_guard<Mutex> lock(smbclient_mutex);
 		smbc_close(fd);
-		smbc_free_context(ctx, 1);
 	}
 
 	/* virtual methods from InputStream */
@@ -83,38 +85,22 @@ static InputStreamPtr
 input_smbclient_open(const char *uri,
 		     Mutex &mutex)
 {
+	auto ctx = SmbclientContext::New();
+
 	const std::lock_guard<Mutex> protect(smbclient_mutex);
 
-	SMBCCTX *ctx = smbc_new_context();
-	if (ctx == nullptr)
-		throw MakeErrno("smbc_new_context() failed");
-
-	SMBCCTX *ctx2 = smbc_init_context(ctx);
-	if (ctx2 == nullptr) {
-		int e = errno;
-		smbc_free_context(ctx, 1);
-		throw MakeErrno(e, "smbc_init_context() failed");
-	}
-
-	ctx = ctx2;
-
 	int fd = smbc_open(uri, O_RDONLY, 0);
-	if (fd < 0) {
-		int e = errno;
-		smbc_free_context(ctx, 1);
-		throw MakeErrno(e, "smbc_open() failed");
-	}
+	if (fd < 0)
+		throw MakeErrno("smbc_open() failed");
 
 	struct stat st;
-	if (smbc_fstat(fd, &st) < 0) {
-		int e = errno;
-		smbc_free_context(ctx, 1);
-		throw MakeErrno(e, "smbc_fstat() failed");
-	}
+	if (smbc_fstat(fd, &st) < 0)
+		throw MakeErrno("smbc_fstat() failed");
 
 	return std::make_unique<MaybeBufferedInputStream>
 		(std::make_unique<SmbclientInputStream>(uri, mutex,
-							ctx, fd, st));
+							std::move(ctx),
+							fd, st));
 }
 
 size_t

src/lib/smbclient/Context.cxx

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2003-2020 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 "Context.hxx"
+#include "system/Error.hxx"
+
+#include <cerrno>
+
+SmbclientContext
+SmbclientContext::New()
+{
+	SMBCCTX *ctx = smbc_new_context();
+	if (ctx == nullptr)
+		throw MakeErrno("smbc_new_context() failed");
+
+	SMBCCTX *ctx2 = smbc_init_context(ctx);
+	if (ctx2 == nullptr) {
+		int e = errno;
+		smbc_free_context(ctx, 1);
+		throw MakeErrno(e, "smbc_init_context() failed");
+	}
+
+	return SmbclientContext(ctx2);
+}

src/lib/smbclient/Context.hxx

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2003-2020 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_SMBCLIENT_CONTEXT_HXX
+#define MPD_SMBCLIENT_CONTEXT_HXX
+
+#include <libsmbclient.h>
+
+#include <utility>
+
+/**
+ * Wrapper for `SMBCCTX*`.
+ */
+class SmbclientContext {
+	SMBCCTX *ctx = nullptr;
+
+	explicit SmbclientContext(SMBCCTX *_ctx) noexcept
+		:ctx(_ctx) {}
+
+public:
+	SmbclientContext() = default;
+
+	~SmbclientContext() noexcept {
+		if (ctx != nullptr)
+			smbc_free_context(ctx, 1);
+	}
+
+	SmbclientContext(SmbclientContext &&src) noexcept
+		:ctx(std::exchange(src.ctx, nullptr)) {}
+
+	SmbclientContext &operator=(SmbclientContext &&src) noexcept {
+		using std::swap;
+		swap(ctx, src.ctx);
+		return *this;
+	}
+
+	/**
+	 * Throws on error.
+	 */
+	static SmbclientContext New();
+};
+
+#endif

src/lib/smbclient/meson.build

@@ -9,6 +9,7 @@ smbclient = static_library(
   'Domain.cxx',
   'Mutex.cxx',
   'Init.cxx',
+  'Context.cxx',
   include_directories: inc,
   dependencies: [
     smbclient_dep,

src/storage/plugins/SmbclientStorage.cxx

@@ -22,6 +22,7 @@
 #include "storage/StorageInterface.hxx"
 #include "storage/FileInfo.hxx"
 #include "lib/smbclient/Init.hxx"
+#include "lib/smbclient/Context.hxx"
 #include "lib/smbclient/Mutex.hxx"
 #include "fs/Traits.hxx"
 #include "thread/Mutex.hxx"
@@ -52,16 +53,11 @@ public:
 class SmbclientStorage final : public Storage {
 	const std::string base;
 
-	SMBCCTX *const ctx;
+	SmbclientContext ctx = SmbclientContext::New();
 
 public:
-	SmbclientStorage(const char *_base, SMBCCTX *_ctx)
-		:base(_base), ctx(_ctx) {}
-
-	~SmbclientStorage() override {
-		const std::lock_guard<Mutex> lock(smbclient_mutex);
-		smbc_free_context(ctx, 1);
-	}
+	explicit SmbclientStorage(const char *_base)
+		:base(_base) {}
 
 	/* virtual methods from class Storage */
 	StorageFileInfo GetInfo(std::string_view uri_utf8, bool follow) override;
@@ -184,18 +180,7 @@ CreateSmbclientStorageURI([[maybe_unused]] EventLoop &event_loop, const char *ba
 
 	SmbclientInit();
 
-	const std::lock_guard<Mutex> protect(smbclient_mutex);
-	SMBCCTX *ctx = smbc_new_context();
-	if (ctx == nullptr)
-		throw MakeErrno("smbc_new_context() failed");
-
-	SMBCCTX *ctx2 = smbc_init_context(ctx);
-	if (ctx2 == nullptr) {
-		AtScopeExit(ctx) { smbc_free_context(ctx, 1); };
-		throw MakeErrno("smbc_new_context() failed");
-	}
-
-	return std::make_unique<SmbclientStorage>(base, ctx2);
+	return std::make_unique<SmbclientStorage>(base);
 }
 
 const StoragePlugin smbclient_storage_plugin = {