Input*: move to input/

src/input/InputStream.hxx

@@ -0,0 +1,301 @@
+/*
+ * 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_INPUT_STREAM_HXX
+#define MPD_INPUT_STREAM_HXX
+
+#include "check.h"
+#include "thread/Mutex.hxx"
+#include "Compiler.h"
+
+#include <string>
+
+#include <assert.h>
+#include <stdint.h>
+
+class Cond;
+class Error;
+struct Tag;
+struct InputPlugin;
+
+struct InputStream {
+	typedef int64_t offset_type;
+
+	/**
+	 * the plugin which implements this input stream
+	 */
+	const InputPlugin &plugin;
+
+	/**
+	 * The absolute URI which was used to open this stream.
+	 */
+	std::string uri;
+
+	/**
+	 * A mutex that protects the mutable attributes of this object
+	 * and its implementation.  It must be locked before calling
+	 * any of the public methods.
+	 *
+	 * This object is allocated by the client, and the client is
+	 * responsible for freeing it.
+	 */
+	Mutex &mutex;
+
+	/**
+	 * A cond that gets signalled when the state of this object
+	 * changes from the I/O thread.  The client of this object may
+	 * wait on it.  Optional, may be nullptr.
+	 *
+	 * This object is allocated by the client, and the client is
+	 * responsible for freeing it.
+	 */
+	Cond &cond;
+
+	/**
+	 * indicates whether the stream is ready for reading and
+	 * whether the other attributes in this struct are valid
+	 */
+	bool ready;
+
+	/**
+	 * if true, then the stream is fully seekable
+	 */
+	bool seekable;
+
+	/**
+	 * the size of the resource, or -1 if unknown
+	 */
+	offset_type size;
+
+	/**
+	 * the current offset within the stream
+	 */
+	offset_type offset;
+
+	/**
+	 * the MIME content type of the resource, or empty if unknown.
+	 */
+	std::string mime;
+
+	InputStream(const InputPlugin &_plugin,
+		    const char *_uri, Mutex &_mutex, Cond &_cond)
+		:plugin(_plugin), uri(_uri),
+		 mutex(_mutex), cond(_cond),
+		 ready(false), seekable(false),
+		 size(-1), offset(0) {
+		assert(_uri != nullptr);
+	}
+
+	/**
+	 * Opens a new input stream.  You may not access it until the "ready"
+	 * flag is set.
+	 *
+	 * @param mutex a mutex that is used to protect this object; must be
+	 * locked before calling any of the public methods
+	 * @param cond a cond that gets signalled when the state of
+	 * this object changes; may be nullptr if the caller doesn't want to get
+	 * notifications
+	 * @return an #InputStream object on success, nullptr on error
+	 */
+	gcc_nonnull_all
+	gcc_malloc
+	static InputStream *Open(const char *uri, Mutex &mutex, Cond &cond,
+				 Error &error);
+
+	/**
+	 * Just like Open(), but waits for the stream to become ready.
+	 * It is a wrapper for Open(), WaitReady() and Check().
+	 */
+	gcc_malloc gcc_nonnull_all
+	static InputStream *OpenReady(const char *uri,
+				      Mutex &mutex, Cond &cond,
+				      Error &error);
+
+	/**
+	 * Close the input stream and free resources.
+	 *
+	 * The caller must not lock the mutex.
+	 */
+	void Close();
+
+	void Lock() {
+		mutex.lock();
+	}
+
+	void Unlock() {
+		mutex.unlock();
+	}
+
+	/**
+	 * Check for errors that may have occurred in the I/O thread.
+	 *
+	 * @return false on error
+	 */
+	bool Check(Error &error);
+
+	/**
+	 * Update the public attributes.  Call before accessing attributes
+	 * such as "ready" or "offset".
+	 */
+	void Update();
+
+	/**
+	 * Wait until the stream becomes ready.
+	 *
+	 * The caller must lock the mutex.
+	 */
+	void WaitReady();
+
+	/**
+	 * Wrapper for WaitReady() which locks and unlocks the mutex;
+	 * the caller must not be holding it already.
+	 */
+	void LockWaitReady();
+
+	gcc_pure
+	const char *GetMimeType() const {
+		assert(ready);
+
+		return mime.empty() ? nullptr : mime.c_str();
+	}
+
+	gcc_nonnull_all
+	void OverrideMimeType(const char *_mime) {
+		assert(ready);
+
+		mime = _mime;
+	}
+
+	gcc_pure
+	offset_type GetSize() const {
+		assert(ready);
+
+		return size;
+	}
+
+	gcc_pure
+	offset_type GetOffset() const {
+		assert(ready);
+
+		return offset;
+	}
+
+	gcc_pure
+	bool IsSeekable() const {
+		assert(ready);
+
+		return seekable;
+	}
+
+	/**
+	 * Determines whether seeking is cheap.  This is true for local files.
+	 */
+	gcc_pure
+	bool CheapSeeking() const;
+
+	/**
+	 * Seeks to the specified position in the stream.  This will most
+	 * likely fail if the "seekable" flag is false.
+	 *
+	 * The caller must lock the mutex.
+	 *
+	 * @param offset the relative offset
+	 * @param whence the base of the seek, one of SEEK_SET, SEEK_CUR, SEEK_END
+	 */
+	bool Seek(offset_type offset, int whence, Error &error);
+
+	/**
+	 * Wrapper for Seek() which locks and unlocks the mutex; the
+	 * caller must not be holding it already.
+	 */
+	bool LockSeek(offset_type offset, int whence, Error &error);
+
+	/**
+	 * Rewind to the beginning of the stream.  This is a wrapper
+	 * for Seek(0, SEEK_SET, error).
+	 */
+	bool Rewind(Error &error);
+	bool LockRewind(Error &error);
+
+	/**
+	 * Returns true if the stream has reached end-of-file.
+	 *
+	 * The caller must lock the mutex.
+	 */
+	gcc_pure
+	bool IsEOF();
+
+	/**
+	 * Wrapper for IsEOF() which locks and unlocks the mutex; the
+	 * caller must not be holding it already.
+	 */
+	gcc_pure
+	bool LockIsEOF();
+
+	/**
+	 * Reads the tag from the stream.
+	 *
+	 * The caller must lock the mutex.
+	 *
+	 * @return a tag object which must be freed by the caller, or
+	 * nullptr if the tag has not changed since the last call
+	 */
+	gcc_malloc
+	Tag *ReadTag();
+
+	/**
+	 * Wrapper for ReadTag() which locks and unlocks the mutex;
+	 * the caller must not be holding it already.
+	 */
+	gcc_malloc
+	Tag *LockReadTag();
+
+	/**
+	 * Returns true if the next read operation will not block: either data
+	 * is available, or end-of-stream has been reached, or an error has
+	 * occurred.
+	 *
+	 * The caller must lock the mutex.
+	 */
+	gcc_pure
+	bool IsAvailable();
+
+	/**
+	 * Reads data from the stream into the caller-supplied buffer.
+	 * Returns 0 on error or eof (check with IsEOF()).
+	 *
+	 * The caller must lock the mutex.
+	 *
+	 * @param is the InputStream object
+	 * @param ptr the buffer to read into
+	 * @param size the maximum number of bytes to read
+	 * @return the number of bytes read
+	 */
+	gcc_nonnull_all
+	size_t Read(void *ptr, size_t size, Error &error);
+
+	/**
+	 * Wrapper for Read() which locks and unlocks the mutex;
+	 * the caller must not be holding it already.
+	 */
+	gcc_nonnull_all
+	size_t LockRead(void *ptr, size_t size, Error &error);
+};
+
+#endif