Imported ngfs libgio. This is a library to create virtual file descriptors, similar to common lisp grey-streams or golang's io.Reader/io.Writer. Now 95% bug-free.

1 files changed, 94 insertions, 0 deletions

diff --git a/sys/man/2/gio b/sys/man/2/gio
new file mode 100644
index 000000000..77e29329f
--- /dev/null
+++ b/sys/man/2/gio
@@ -0,0 +1,94 @@
+.TH GIO 2
+.SH NAME
+gopen, gclose, gseek, gread, gwrite, fd2gio \- Programmable streams
+.SH SYNOPSIS
+.B #include <u.h>
+.br
+.B #include <libc.h>
+.br
+.B #include <gio.h>
+.PP
+.ft L
+.nf
+typedef struct ReadWriter {
+	RWLock;
+	int (*open)(ReadWriter*);
+	int (*close)(ReadWriter*);
+	long (*pread)(ReadWriter*, void*, long, vlong);
+	long (*pwrite)(ReadWriter*, void*, long, vlong);
+	void *aux;
+	u64int offset;
+	u64int length;
+} ReadWriter;
+.fi
+.PP
+.B
+int gopen(ReadWriter *r, void *aux)
+.PP
+.B
+int gclose(int gfd)
+.PP
+.B
+vlong gseek(int gfd, vlong offset, int whence)
+.PP
+.B
+long gread(int gfd, void *buf, long nbytes, vlong offset)
+.PP
+.B
+long gwrite(int gfd, void *buf, long nbytes, vlong offset)
+.PP
+.B
+int fd2gio(int fd)
+.SH DESCRIPTION
+.I gopen
+takes a ReadWriter struct and creates a new instance of a gio fd.
+.I aux
+is an auxillary argument that may or may not be optional depending on how the gio stream is implemented.
+.I gclose
+closes a gio fd and frees any resources allocated to it.
+.I gseek
+changes the fd in a similar way to
+.IR seek (2).
+.I gread
+and
+.I gwrite
+are the gio equivalents to
+.IR pread (2)
+and
+.IR pwrite (2).
+They are functionally equivalent and have nearly the same usage.
+.I fd2gio
+takes a Plan 9 file descriptor and returns a gio descriptor made from that fd.
+.SH SOURCE
+.B /sys/src/libgio
+.SH NOTES
+The gio functions automatically lock the ReadWriter struct in use hopefully making things work better with
+.IR thread (2).
+.SH BUGS
+Things get interesting with
+.IR rfork (2)
+when you disable shared memory.
+.br
+The file descriptor table is poorly implemented.
+.br
+You cannot easily mix gio file descriptors with functions that want Plan 9 ones.
+.br
+
+.SH SEE ALSO
+.IR read (2),
+.IR seek (2),
+.IR open (2)
+.SH DIAGNOSTICS
+By default, no. Users can have their methods set 
+.I errstr,
+and
+.I gopen,
+.I gclose,
+.I gread,
+and
+.I gwrite
+will return -2 if a function pointer is nil.
+.SH HISTORY
+First appeared as part of
+.IR ngfs (8)
+in September 2015; imported into 9front February 2016.