input/rewind: move code to class ProxyInputStream

Makefile.am

@@ -1032,6 +1032,7 @@ libinput_a_SOURCES = \
 	src/input/InputPlugin.hxx \
 	src/input/TextInputStream.cxx src/input/TextInputStream.hxx \
 	src/input/ThreadInputStream.cxx src/input/ThreadInputStream.hxx \
+	src/input/ProxyInputStream.cxx src/input/ProxyInputStream.hxx \
 	src/input/plugins/RewindInputPlugin.cxx src/input/plugins/RewindInputPlugin.hxx \
 	src/input/plugins/FileInputPlugin.cxx src/input/plugins/FileInputPlugin.hxx
 

src/input/ProxyInputStream.cxx

@@ -0,0 +1,97 @@
+/*
+ * 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 "ProxyInputStream.hxx"
+#include "tag/Tag.hxx"
+
+#include <assert.h>
+
+ProxyInputStream::ProxyInputStream(InputStream *_input)
+	:InputStream(_input->GetURI(), _input->mutex, _input->cond),
+	 input(*_input) {}
+
+ProxyInputStream::~ProxyInputStream()
+{
+	delete &input;
+}
+
+void
+ProxyInputStream::CopyAttributes()
+{
+	if (input.IsReady()) {
+		if (!IsReady()) {
+			if (input.HasMimeType())
+				SetMimeType(input.GetMimeType());
+
+			size = input.GetSize();
+			seekable = input.IsSeekable();
+			SetReady();
+		}
+
+		offset = input.GetOffset();
+	}
+}
+
+bool
+ProxyInputStream::Check(Error &error)
+{
+	return input.Check(error);
+}
+
+void
+ProxyInputStream::Update()
+{
+	input.Update();
+	CopyAttributes();
+}
+
+bool
+ProxyInputStream::Seek(offset_type new_offset, int whence, Error &error)
+{
+	bool success = input.Seek(new_offset, whence, error);
+	CopyAttributes();
+	return success;
+}
+
+bool
+ProxyInputStream::IsEOF()
+{
+	return input.IsEOF();
+}
+
+Tag *
+ProxyInputStream::ReadTag()
+{
+	return input.ReadTag();
+}
+
+bool
+ProxyInputStream::IsAvailable()
+{
+	return input.IsAvailable();
+}
+
+size_t
+ProxyInputStream::Read(void *ptr, size_t read_size, Error &error)
+{
+	size_t nbytes = input.Read(ptr, read_size, error);
+	CopyAttributes();
+	return nbytes;
+}

src/input/ProxyInputStream.hxx

@@ -0,0 +1,64 @@
+/*
+ * 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_PROXY_INPUT_STREAM_HXX
+#define MPD_PROXY_INPUT_STREAM_HXX
+
+#include "InputStream.hxx"
+
+struct Tag;
+
+/**
+ * An #InputStream that forwards all methods call to another
+ * #InputStream instance.  This can be used as a base class to
+ * override selected methods.
+ */
+class ProxyInputStream : public InputStream {
+protected:
+	InputStream &input;
+
+public:
+	gcc_nonnull_all
+	ProxyInputStream(InputStream *_input);
+
+	virtual ~ProxyInputStream();
+
+	ProxyInputStream(const ProxyInputStream &) = delete;
+	ProxyInputStream &operator=(const ProxyInputStream &) = delete;
+
+	/* virtual methods from InputStream */
+	bool Check(Error &error) override;
+	void Update() override;
+	bool Seek(offset_type new_offset, int whence, Error &error) override;
+	bool IsEOF() override;
+	Tag *ReadTag() override;
+	bool IsAvailable() override;
+	size_t Read(void *ptr, size_t read_size, Error &error) override;
+
+protected:
+	/**
+	 * Copy public attributes from the underlying input stream to the
+	 * "rewind" input stream.  This function is called when a method of
+	 * the underlying stream has returned, which may have modified these
+	 * attributes.
+	 */
+	void CopyAttributes();
+};
+
+#endif

src/input/plugins/RewindInputPlugin.cxx

@@ -19,14 +19,12 @@
 
 #include "config.h"
 #include "RewindInputPlugin.hxx"
-#include "../InputStream.hxx"
+#include "../ProxyInputStream.hxx"
 
 #include <assert.h>
 #include <string.h>
 
-class RewindInputStream final : public InputStream {
-	InputStream *input;
-
+class RewindInputStream final : public ProxyInputStream {
 	/**
 	 * The read position within the buffer.  Undefined as long as
 	 * ReadingFromBuffer() returns false.
@@ -50,36 +48,19 @@ class RewindInputStream final : public InputStream {
 
 public:
 	RewindInputStream(InputStream *_input)
-		:InputStream(_input->GetURI(),
-			     _input->mutex, _input->cond),
-		 input(_input), tail(0) {
-	}
-
-	~RewindInputStream() {
-		delete input;
+		:ProxyInputStream(_input),
+		 tail(0) {
 	}
 
 	/* virtual methods from InputStream */
 
-	bool Check(Error &error) override {
-		return input->Check(error);
-	}
-
 	void Update() override {
 		if (!ReadingFromBuffer())
-			CopyAttributes();
+			ProxyInputStream::Update();
 	}
 
 	bool IsEOF() override {
-		return !ReadingFromBuffer() && input->IsEOF();
-	}
-
-	Tag *ReadTag() override {
-		return input->ReadTag();
-	}
-
-	bool IsAvailable() override {
-		return input->IsAvailable();
+		return !ReadingFromBuffer() && ProxyInputStream::IsEOF();
 	}
 
 	size_t Read(void *ptr, size_t size, Error &error) override;
@@ -91,30 +72,7 @@ private:
 	 * buffer contain more data for the next read operation?
 	 */
 	bool ReadingFromBuffer() const {
-		return tail > 0 && offset < input->GetOffset();
-	}
-
-	/**
-	 * Copy public attributes from the underlying input stream to the
-	 * "rewind" input stream.  This function is called when a method of
-	 * the underlying stream has returned, which may have modified these
-	 * attributes.
-	 */
-	void CopyAttributes() {
-		const InputStream *src = input;
-
-		assert(src != this);
-
-		if (!IsReady() && src->IsReady()) {
-			if (src->HasMimeType())
-				SetMimeType(src->GetMimeType());
-
-			size = src->GetSize();
-			seekable = src->IsSeekable();
-			SetReady();
-		}
-
-		offset = src->GetOffset();
+		return tail > 0 && offset < input.GetOffset();
 	}
 };
 
@@ -125,7 +83,7 @@ RewindInputStream::Read(void *ptr, size_t read_size, Error &error)
 		/* buffered read */
 
 		assert(head == (size_t)offset);
-		assert(tail == (size_t)input->GetOffset());
+		assert(tail == (size_t)input.GetOffset());
 
 		if (read_size > tail - head)
 			read_size = tail - head;
@@ -138,9 +96,9 @@ RewindInputStream::Read(void *ptr, size_t read_size, Error &error)
 	} else {
 		/* pass method call to underlying stream */
 
-		size_t nbytes = input->Read(ptr, read_size, error);
+		size_t nbytes = input.Read(ptr, read_size, error);
 
-		if (input->GetOffset() > (offset_type)sizeof(buffer))
+		if (input.GetOffset() > (offset_type)sizeof(buffer))
 			/* disable buffering */
 			tail = 0;
 		else if (tail == (size_t)offset) {
@@ -149,7 +107,7 @@ RewindInputStream::Read(void *ptr, size_t read_size, Error &error)
 			memcpy(buffer + tail, ptr, nbytes);
 			tail += nbytes;
 
-			assert(tail == (size_t)input->GetOffset());
+			assert(tail == (size_t)input.GetOffset());
 		}
 
 		CopyAttributes();
@@ -158,7 +116,7 @@ RewindInputStream::Read(void *ptr, size_t read_size, Error &error)
 	}
 }
 
-inline bool
+bool
 RewindInputStream::Seek(offset_type new_offset, int whence,
 			Error &error)
 {
@@ -170,21 +128,18 @@ RewindInputStream::Seek(offset_type new_offset, int whence,
 
 		assert(!ReadingFromBuffer() ||
 		       head == (size_t)offset);
-		assert(tail == (size_t)input->GetOffset());
+		assert(tail == (size_t)input.GetOffset());
 
 		head = (size_t)new_offset;
 		offset = new_offset;
 
 		return true;
 	} else {
-		bool success = input->Seek(new_offset, whence, error);
-		CopyAttributes();
-
 		/* disable the buffer, because input has left the
 		   buffered range now */
 		tail = 0;
 
-		return success;
+		return ProxyInputStream::Seek(new_offset, whence, error);
 	}
 }