Make cairo_output_stream_t an embeddable type.

Most internal cairo types are transparent within cairo and have init and fini
functions to intialize and finialize them in place.  This way they can be
easily be embedded in other structs or derived from.  Initially, the
cairo_output_stream_t type was proposed as a publically visible type and
thus kept opaque.  However, now it's only used internally and derived from
in a number of places so let's make it an embeddable type for consistency
and ease of use.

The patch keeps _cairo_output_stream_create() and _cairo_output_stream_close()
around for (internal) backwards compatibility by deriving a
cairo_output_stream_with_closure_t stream type.

The patch also moves all cairo_output_stream_t functions out of cairoint.h
and into new file cairo-output-stream-private.h, thus chipping away at the
monolithic cairoint.h.

1 files changed, 56 insertions, 20 deletions

diff --git a/src/cairo-output-stream.c b/src/cairo-output-stream.c
index 5ef36e5f..c71b89fa 100644
--- a/src/cairo-output-stream.c
+++ b/src/cairo-output-stream.c
@@ -1,4 +1,4 @@
-/* cairo_output_stream.c: Output stream abstraction
+/* cairo-output-stream.c: Output stream abstraction
  *
  * Copyright © 2005 Red Hat, Inc
  *
@@ -38,24 +38,35 @@
 #include <locale.h>
 #include <ctype.h>
 #include "cairoint.h"
+#include "cairo-output-stream-private.h"
 
 #ifdef _MSC_VER
 #define snprintf _snprintf
 #endif /* _MSC_VER */
 
-struct _cairo_output_stream {
-    cairo_write_func_t		write_func;
-    cairo_close_func_t		close_func;
-    void			*closure;
-    unsigned long		position;
-    cairo_status_t		status;
-    cairo_bool_t		closed;
-};
+
+cairo_private void
+_cairo_output_stream_init (cairo_output_stream_t            *stream,
+			   cairo_output_stream_write_func_t  write_func,
+			   cairo_output_stream_close_func_t  close_func)
+{
+    stream->write_func = write_func;
+    stream->close_func = close_func;
+    stream->position = 0;
+    stream->status = CAIRO_STATUS_SUCCESS;
+    stream->closed = FALSE;
+}
+
+cairo_private void
+_cairo_output_stream_fini (cairo_output_stream_t *stream)
+{
+    _cairo_output_stream_close (stream);
+}
+
 
 const cairo_output_stream_t cairo_output_stream_nil = {
     NULL, /* write_func */
     NULL, /* close_func */
-    NULL, /* closure */
     0,    /* position */
     CAIRO_STATUS_NO_MEMORY,
     FALSE /* closed */
@@ -64,31 +75,56 @@ const cairo_output_stream_t cairo_output_stream_nil = {
 static const cairo_output_stream_t cairo_output_stream_nil_write_error = {
     NULL, /* write_func */
     NULL, /* close_func */
-    NULL, /* closure */
     0,    /* position */
     CAIRO_STATUS_WRITE_ERROR,
     FALSE /* closed */
 };
 
+typedef struct _cairo_output_stream_with_closure {
+    cairo_output_stream_t	 base;
+    cairo_write_func_t		 write_func;
+    cairo_close_func_t		 close_func;
+    void			*closure;
+} cairo_output_stream_with_closure_t;
+
+
+static cairo_status_t
+closure_write (cairo_output_stream_t *stream,
+	       const unsigned char *data, unsigned int length)
+{
+    cairo_output_stream_with_closure_t *stream_with_closure =
+	(cairo_output_stream_with_closure_t *) stream;
+
+    return stream_with_closure->write_func (stream_with_closure->closure,
+					    data, length);
+}
+
+static cairo_status_t
+closure_close (cairo_output_stream_t *stream)
+{
+    cairo_output_stream_with_closure_t *stream_with_closure =
+	(cairo_output_stream_with_closure_t *) stream;
+
+    return stream_with_closure->close_func (stream_with_closure->closure);
+}
+
 cairo_output_stream_t *
 _cairo_output_stream_create (cairo_write_func_t		write_func,
 			     cairo_close_func_t		close_func,
 			     void			*closure)
 {
-    cairo_output_stream_t *stream;
+    cairo_output_stream_with_closure_t *stream;
 
-    stream = malloc (sizeof (cairo_output_stream_t));
+    stream = malloc (sizeof (cairo_output_stream_with_closure_t));
     if (stream == NULL)
 	return (cairo_output_stream_t *) &cairo_output_stream_nil;
 
+    _cairo_output_stream_init (&stream->base, closure_write, closure_close);
     stream->write_func = write_func;
     stream->close_func = close_func;
     stream->closure = closure;
-    stream->position = 0;
-    stream->status = CAIRO_STATUS_SUCCESS;
-    stream->closed = FALSE;
 
-    return stream;
+    return &stream->base;
 }
 
 void
@@ -106,7 +142,7 @@ _cairo_output_stream_close (cairo_output_stream_t *stream)
     }
 
     if (stream->close_func) {
-	status = stream->close_func (stream->closure);
+	status = stream->close_func (stream);
 	if (status)
 	    stream->status = status;
     }
@@ -120,7 +156,7 @@ _cairo_output_stream_destroy (cairo_output_stream_t *stream)
     if (stream == NULL)
 	return;
 
-    _cairo_output_stream_close (stream);
+    _cairo_output_stream_fini (stream);
     free (stream);
 }
 
@@ -134,7 +170,7 @@ _cairo_output_stream_write (cairo_output_stream_t *stream,
     if (stream->status)
 	return;
 
-    stream->status = stream->write_func (stream->closure, data, length);
+    stream->status = stream->write_func (stream, data, length);
     stream->position += length;
 }