Move files to prepare for assimilation into core

[libs/core.git] / source / io / base.h

diff --git a/source/io/base.h b/source/io/base.h
new file mode 100644 (file)
index 0000000..774d034
--- /dev/null
+++ b/source/io/base.h
@@ -0,0 +1,121 @@
+#ifndef MSP_IO_BASE_H_
+#define MSP_IO_BASE_H_
+
+#include <sigc++/sigc++.h>
+#include "mode.h"
+#include "poll.h"
+#include "types.h"
+
+namespace Msp {
+namespace IO {
+
+/**
+Common interface for all I/O objects.
+
+A derived class must call set_events(P_NONE) before it is destroyed to avoid
+leaving stale pointers in an EventDispatcher.
+*/
+class Base
+{
+public:
+       /** Emitted when there is data available for reading.  If all data is not
+       read, the signal is emitted again immediately. */
+       sigc::signal<void> signal_data_available;
+
+       /** Emitted when there is no more data to be read. */
+       sigc::signal<void> signal_end_of_file;
+
+       /** Emitted when there is a nonlinearity in I/O (such as a file being
+       seeked) and any data buffered by upper layers needs to be flushed. */
+       sigc::signal<void> signal_flush_required;
+
+       /** Emitted when the I/O object has closed. */
+       sigc::signal<void> signal_closed;
+
+       /** Emitted when the mask of interesting events changes.  Mainly for use by
+       EventDispatcher. */
+       sigc::signal<void, PollEvent> signal_events_changed;
+
+       /** Emitted when the object is deleted.  Mainly for use by
+       EventDispatcher. */
+       sigc::signal<void> signal_deleted;
+
+protected:
+       Mode mode;
+       PollEvent events;
+       bool eof_flag;
+
+       Base();
+private:
+       Base(const Base &);
+       Base &operator=(const Base &);
+public:
+       virtual ~Base();
+
+       /** Sets blocking mode.  When blocking is enabled, most operations won't
+       return until they can make progress.  When blocking is disabled, these
+       operations may return immediately with a return code indicating that nothing
+       was done.
+
+       Blocking is enabled by default. */
+       virtual void set_block(bool) { }
+
+       /** Returns the current mode flags. */
+       Mode get_mode() const { return mode; }
+
+protected:
+       virtual unsigned do_write(const char *, unsigned) =0;
+       virtual unsigned do_read(char *, unsigned) =0;
+
+public:
+       /** Writes data from a buffer.  Subject to blocking.  Returns the number of
+       bytes written, which may be zero for a non-blockin operation. */
+       unsigned write(const char *b, unsigned c) { return do_write(b, c); }
+
+       /** Writes a string.  This is identical to calling
+       write(s.data(), s.size()). */
+       unsigned write(const std::string &s) { return do_write(s.data(), s.size()); }
+
+       /** Writes a single character.  This is identical to calling
+       write(&c, 1). */
+       virtual unsigned put(char c) { return do_write(&c, 1); }
+
+       /** Reads data into a buffer.  Subject to blocking.  Returns the number of
+       bytes read, which may be zero for a non-blocking operation. */
+       unsigned read(char *b, unsigned c) { return do_read(b, c); }
+
+       /** Reads characters up to the next linefeed or end-of-file.  The linefeed
+       is not included in the line.  Returns true if a line was successfully read,
+       false otherwise. */
+       virtual bool getline(std::string &);
+
+       /** Reads a single character.  Returns -1 if no character was available due
+       to end-of-file or non-blocking operation. */
+       virtual int get();
+
+       /** Returns the end-of-file flag. */
+       bool eof() const { return eof_flag; }
+
+protected:
+       void set_events(PollEvent);
+
+public:
+       /** Returns a mask of the currently interesting events.  Used by
+       EventDispatcher. */
+       PollEvent get_events() const { return events; }
+
+       /** Returns a handle for polling.  Should throw if the object does not have
+       an event handle. */
+       virtual Handle get_event_handle() =0;
+
+       /** Notifies the object of an event.  Used by EventDispatcher. */
+       void event(PollEvent);
+
+protected:
+       virtual void on_event(PollEvent) { }
+};
+
+} // namespace IO
+} // namespace Msp
+
+#endif