storage/Interface: add virtual method OpenFile()

This should replace most InputStream::Open() calls because it is a
chance to reuse existing resources (e.g. the NFS connection).  No such
optimization is implemented, currently (and the method is not yet used
by anybody).

src/storage/CompositeStorage.cxx

@@ -4,6 +4,7 @@
 #include "CompositeStorage.hxx"
 #include "FileInfo.hxx"
 #include "fs/AllocatedPath.hxx"
+#include "input/InputStream.hxx"
 #include "util/IterableSplitString.hxx"
 #include "util/StringCompare.hxx"
 #include "util/StringSplit.hxx"
@@ -320,3 +321,15 @@ CompositeStorage::MapToRelativeUTF8(std::string_view uri) const noexcept
 
 	return relative_buffer;
 }
+
+InputStreamPtr
+CompositeStorage::OpenFile(std::string_view uri_utf8, Mutex &_mutex)
+{
+	const std::lock_guard<Mutex> lock(mutex);
+
+	auto f = FindStorage(uri_utf8);
+	if (f.directory->storage == nullptr)
+		return nullptr;
+
+	return f.directory->storage->OpenFile(f.uri, _mutex);
+}

src/storage/CompositeStorage.hxx

@@ -127,6 +127,8 @@ public:
 
 	std::string_view MapToRelativeUTF8(std::string_view uri) const noexcept override;
 
+	InputStreamPtr OpenFile(std::string_view uri_utf8, Mutex &mutex) override;
+
 private:
 	template<typename T>
 	void VisitMounts(std::string &uri, const Directory &directory,

src/storage/StorageInterface.hxx

@@ -3,6 +3,9 @@
 
 #pragma once
 
+#include "input/Ptr.hxx"
+#include "thread/Mutex.hxx"
+
 #include <memory>
 #include <string>
 #include <string_view>
@@ -69,4 +72,12 @@ public:
 	 */
 	[[nodiscard]] [[gnu::pure]]
 	virtual std::string_view MapToRelativeUTF8(std::string_view uri_utf8) const noexcept = 0;
+
+	/**
+	 * Open a file in this storage as an #InputStream.
+	 *
+	 * Throws on error
+	 */
+	[[nodiscard]]
+	virtual InputStreamPtr OpenFile(std::string_view uri_utf8, Mutex &mutex) = 0;
 };

src/storage/plugins/CurlStorage.cxx

@@ -6,6 +6,9 @@
 #include "storage/StorageInterface.hxx"
 #include "storage/FileInfo.hxx"
 #include "storage/MemoryDirectoryReader.hxx"
+#include "input/InputStream.hxx"
+#include "input/RewindInputStream.hxx"
+#include "input/plugins/CurlInputPlugin.hxx"
 #include "lib/curl/HttpStatusError.hxx"
 #include "lib/curl/Init.hxx"
 #include "lib/curl/Global.hxx"
@@ -52,6 +55,8 @@ public:
 	[[nodiscard]] std::string MapUTF8(std::string_view uri_utf8) const noexcept override;
 
 	[[nodiscard]] std::string_view MapToRelativeUTF8(std::string_view uri_utf8) const noexcept override;
+
+	InputStreamPtr OpenFile(std::string_view uri_utf8, Mutex &mutex) override;
 };
 
 std::string
@@ -71,6 +76,12 @@ CurlStorage::MapToRelativeUTF8(std::string_view uri_utf8) const noexcept
 					CurlUnescape(uri_utf8));
 }
 
+InputStreamPtr
+CurlStorage::OpenFile(std::string_view uri_utf8, Mutex &mutex)
+{
+	return input_rewind_open(OpenCurlInputStream(MapUTF8(uri_utf8), {}, mutex));
+}
+
 class BlockingHttpRequest : protected CurlResponseHandler {
 	InjectEvent defer_start;
 

src/storage/plugins/LocalStorage.cxx

@@ -5,6 +5,8 @@
 #include "storage/StoragePlugin.hxx"
 #include "storage/StorageInterface.hxx"
 #include "storage/FileInfo.hxx"
+#include "input/InputStream.hxx"
+#include "input/LocalOpen.hxx"
 #include "fs/FileInfo.hxx"
 #include "fs/AllocatedPath.hxx"
 #include "fs/DirectoryReader.hxx"
@@ -50,6 +52,8 @@ public:
 
 	[[nodiscard]] std::string_view MapToRelativeUTF8(std::string_view uri_utf8) const noexcept override;
 
+	InputStreamPtr OpenFile(std::string_view uri_utf8, Mutex &mutex) override;
+
 private:
 	[[nodiscard]] AllocatedPath MapFSOrThrow(std::string_view uri_utf8) const;
 };
@@ -112,6 +116,16 @@ LocalStorage::MapToRelativeUTF8(std::string_view uri_utf8) const noexcept
 	return PathTraitsUTF8::Relative(base_utf8, uri_utf8);
 }
 
+InputStreamPtr
+LocalStorage::OpenFile(std::string_view uri_utf8, Mutex &mutex)
+{
+	auto path = MapFS(uri_utf8);
+	if (path == nullptr)
+		return nullptr;
+
+	return OpenLocalInputStream(path, mutex);
+}
+
 StorageFileInfo
 LocalStorage::GetInfo(std::string_view uri_utf8, bool follow)
 {

src/storage/plugins/NfsStorage.cxx

@@ -11,6 +11,7 @@
 #include "lib/nfs/Lease.hxx"
 #include "lib/nfs/Connection.hxx"
 #include "lib/nfs/Glue.hxx"
+#include "input/InputStream.hxx"
 #include "fs/AllocatedPath.hxx"
 #include "thread/Mutex.hxx"
 #include "thread/Cond.hxx"
@@ -94,6 +95,8 @@ public:
 
 	[[nodiscard]] std::string_view MapToRelativeUTF8(std::string_view uri_utf8) const noexcept override;
 
+	InputStreamPtr OpenFile(std::string_view uri_utf8, Mutex &mutex) override;
+
 	/* virtual methods from NfsLease */
 	void OnNfsConnectionReady() noexcept final {
 		assert(state == State::CONNECTING);
@@ -246,6 +249,14 @@ NfsStorage::MapToRelativeUTF8(std::string_view uri_utf8) const noexcept
 	return PathTraitsUTF8::Relative(base, uri_utf8);
 }
 
+InputStreamPtr
+NfsStorage::OpenFile(std::string_view uri_utf8, Mutex &_mutex)
+{
+	// TODO create NfsInputStream directly
+	auto uri = MapUTF8(uri_utf8);
+	return InputStream::Open(uri.c_str(), _mutex);
+}
+
 static void
 Copy(StorageFileInfo &info, const struct nfs_stat_64 &st) noexcept
 {

src/storage/plugins/SmbclientStorage.cxx

@@ -5,6 +5,7 @@
 #include "storage/StoragePlugin.hxx"
 #include "storage/StorageInterface.hxx"
 #include "storage/FileInfo.hxx"
+#include "input/InputStream.hxx"
 #include "lib/smbclient/Init.hxx"
 #include "lib/smbclient/Context.hxx"
 #include "fs/Traits.hxx"
@@ -63,6 +64,8 @@ public:
 	[[nodiscard]] std::string MapUTF8(std::string_view uri_utf8) const noexcept override;
 
 	[[nodiscard]] std::string_view MapToRelativeUTF8(std::string_view uri_utf8) const noexcept override;
+
+	InputStreamPtr OpenFile(std::string_view uri_utf8, Mutex &file_mutex) override;
 };
 
 std::string
@@ -113,6 +116,13 @@ SmbclientStorage::GetInfo(std::string_view uri_utf8, [[maybe_unused]] bool follo
 	return ::GetInfo(ctx, mutex, mapped.c_str());
 }
 
+InputStreamPtr
+SmbclientStorage::OpenFile(std::string_view uri_utf8, Mutex &file_mutex)
+{
+	auto uri = MapUTF8(uri_utf8);
+	return InputStream::Open(uri.c_str(), file_mutex);
+}
+
 std::unique_ptr<StorageDirectoryReader>
 SmbclientStorage::OpenDirectory(std::string_view uri_utf8)
 {

src/storage/plugins/UdisksStorage.cxx

@@ -6,6 +6,8 @@
 #include "storage/StoragePlugin.hxx"
 #include "storage/StorageInterface.hxx"
 #include "storage/FileInfo.hxx"
+#include "input/InputStream.hxx"
+#include "input/LocalOpen.hxx"
 #include "lib/fmt/ExceptionFormatter.hxx"
 #include "lib/fmt/RuntimeError.hxx"
 #include "lib/dbus/Glue.hxx"
@@ -113,6 +115,12 @@ public:
 
 	std::string_view MapToRelativeUTF8(std::string_view uri_utf8) const noexcept override;
 
+	InputStreamPtr OpenFile(std::string_view uri_utf8, Mutex &file_mutex) override {
+		MountWait();
+		const auto path = mounted_storage->MapFS(uri_utf8);
+		return OpenLocalInputStream(path, file_mutex);
+	}
+
 private:
 	void SetMountPoint(Path mount_point);
 	void LockSetMountPoint(Path mount_point);

src/storage/plugins/meson.build

@@ -50,6 +50,8 @@ storage_plugins = static_library(
     expat_dep,
     nfs_dep,
     smbclient_dep,
+    input_glue_dep,
+    archive_glue_dep,
   ],
 )