[cairo-output-stream] Introduce _cairo_output_stream_create_in_error()

Use a utility function to wrap an incoming error status into a new
error stream. As a side-effect, all error streams must be destroyed as
in the general case the caller can not distinguish between a static
error object and one allocated to hold an unusual error status.

src/cairo-base85-stream.c

@@ -113,6 +113,9 @@ _cairo_base85_stream_create (cairo_output_stream_t *output)
 {
     cairo_base85_stream_t *stream;
 
+    if (output->status)
+	return _cairo_output_stream_create_in_error (output->status);
+
     stream = malloc (sizeof (cairo_base85_stream_t));
     if (stream == NULL) {
 	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);

src/cairo-deflate-stream.c

@@ -117,11 +117,8 @@ _cairo_deflate_stream_create (cairo_output_stream_t *output)
 {
     cairo_deflate_stream_t *stream;
 
-    if (output->status) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
-
+    if (output->status)
+	return _cairo_output_stream_create_in_error (output->status);
 
     stream = malloc (sizeof (cairo_deflate_stream_t));
     if (stream == NULL) {

src/cairo-output-stream-private.h

@@ -87,6 +87,9 @@ _cairo_output_stream_create (cairo_write_func_t		write_func,
 			     cairo_close_func_t		close_func,
 			     void			*closure);
 
+cairo_private cairo_output_stream_t *
+_cairo_output_stream_create_in_error (cairo_status_t status);
+
 /* Returns the final status value associated with this object, just
  * before its last gasp. This final status value will capture any
  * status failure returned by the stream's close_func as well. */

src/cairo-output-stream.c

@@ -134,6 +134,29 @@ _cairo_output_stream_create (cairo_write_func_t		write_func,
     return &stream->base;
 }
 
+cairo_output_stream_t *
+_cairo_output_stream_create_in_error (cairo_status_t status)
+{
+    cairo_output_stream_t *stream;
+
+    /* check for the common ones */
+    if (status == CAIRO_STATUS_NO_MEMORY)
+	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
+    if (status == CAIRO_STATUS_WRITE_ERROR)
+	return (cairo_output_stream_t *) &_cairo_output_stream_nil_write_error;
+
+    stream = malloc (sizeof (cairo_output_stream_t));
+    if (stream == NULL) {
+	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
+	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
+    }
+
+    _cairo_output_stream_init (stream, NULL, NULL);
+    stream->status = status;
+
+    return stream;
+}
+
 cairo_status_t
 _cairo_output_stream_close (cairo_output_stream_t *stream)
 {
@@ -165,8 +188,7 @@ _cairo_output_stream_destroy (cairo_output_stream_t *stream)
 {
     cairo_status_t status;
 
-    if (stream == NULL)
-	return _cairo_error (CAIRO_STATUS_NULL_POINTER);
+    assert (stream != NULL);
 
     if (stream == &_cairo_output_stream_nil ||
 	stream == &_cairo_output_stream_nil_write_error)

src/cairo-ps-surface.c

@@ -176,6 +176,9 @@ _word_wrap_stream_create (cairo_output_stream_t *output, int max_column)
 {
     word_wrap_stream_t *stream;
 
+    if (output->status)
+	return _cairo_output_stream_create_in_error (output->status);
+
     stream = malloc (sizeof (word_wrap_stream_t));
     if (stream == NULL) {
 	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
@@ -301,7 +304,7 @@ _cairo_ps_surface_emit_path (cairo_ps_surface_t	   *surface,
     word_wrap = _word_wrap_stream_create (stream, 79);
     status = _cairo_output_stream_get_status (word_wrap);
     if (status)
-	return status;
+	return _cairo_output_stream_destroy (word_wrap);
 
     path_info.surface = surface;
     path_info.stream = word_wrap;
@@ -3255,9 +3258,10 @@ _cairo_ps_surface_show_glyphs (void		     *abstract_surface,
             _cairo_output_stream_printf (surface->stream, "<%02x> S\n", glyph_ids[i].glyph_id);
         } else {
             word_wrap = _word_wrap_stream_create (surface->stream, 79);
-	    status = _cairo_output_stream_get_status (word_wrap);
-	    if (status)
+	    if (_cairo_output_stream_get_status (word_wrap)) {
+		status = _cairo_output_stream_destroy (word_wrap);
 		goto fail;
+	    }
 
             _cairo_output_stream_printf (word_wrap, "<");
             for (j = i; j < last+1; j++)

src/cairo-type1-fallback.c

@@ -601,10 +601,8 @@ cairo_type1_font_write_private_dict (cairo_type1_font_t *font,
         cairo_type1_write_stream_encrypted,
         NULL,
         font);
-    if (encrypted_output == NULL) {
-	status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
-	goto fail;
-    }
+    if (_cairo_output_stream_get_status (encrypted_output))
+	return  _cairo_output_stream_destroy (encrypted_output);
 
     /* Note: the first four spaces at the start of this private dict
      * are the four "random" bytes of plaintext required by the
@@ -697,6 +695,8 @@ cairo_type1_font_generate (cairo_type1_font_t *font, const char *name)
 	return status;
 
     font->output = _cairo_output_stream_create (cairo_type1_write_stream, NULL, font);
+    if (_cairo_output_stream_get_status (font->output))
+	return _cairo_output_stream_destroy (font->output);
 
     status = cairo_type1_font_write (font, name);
     if (status)

src/cairo-type1-subset.c

@@ -1126,9 +1126,10 @@ cairo_type1_font_subset_generate (void       *abstract_font,
 	goto fail;
 
     font->output = _cairo_output_stream_create (type1_font_write, NULL, font);
-    status = _cairo_output_stream_get_status (font->output);
-    if (status)
+    if (_cairo_output_stream_get_status (font->output)) {
+	status = _cairo_output_stream_destroy (font->output);
 	goto fail;
+    }
 
     status = cairo_type1_font_subset_write (font, name);
     if (status)