stream: Do not reference error output streams directly

This makes it possible to observe the creation of
cairo_output_stream_t error objects by breaking on
_cairo_output_stream_create_in_error() and makes the code cleaner by
passing around the status obtained from _cairo_error() instead of
throwing the error.

7 files changed, 29 insertions, 58 deletions

diff --git a/src/cairo-base64-stream.c b/src/cairo-base64-stream.c
index 636431372..2732fb3ac 100644
--- a/src/cairo-base64-stream.c
+++ b/src/cairo-base64-stream.c
@@ -126,10 +126,8 @@ _cairo_base64_stream_create (cairo_output_stream_t *output)
 	return _cairo_output_stream_create_in_error (output->status);
 
     stream = malloc (sizeof (cairo_base64_stream_t));
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (&stream->base,
 			       _cairo_base64_stream_write,
diff --git a/src/cairo-base85-stream.c b/src/cairo-base85-stream.c
index f81affb49..d04a4f588 100644
--- a/src/cairo-base85-stream.c
+++ b/src/cairo-base85-stream.c
@@ -115,10 +115,8 @@ _cairo_base85_stream_create (cairo_output_stream_t *output)
 	return _cairo_output_stream_create_in_error (output->status);
 
     stream = malloc (sizeof (cairo_base85_stream_t));
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (&stream->base,
 			       _cairo_base85_stream_write,
diff --git a/src/cairo-deflate-stream.c b/src/cairo-deflate-stream.c
index ae23bda94..aa6a52f72 100644
--- a/src/cairo-deflate-stream.c
+++ b/src/cairo-deflate-stream.c
@@ -125,10 +125,8 @@ _cairo_deflate_stream_create (cairo_output_stream_t *output)
 	return _cairo_output_stream_create_in_error (output->status);
 
     stream = malloc (sizeof (cairo_deflate_stream_t));
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (&stream->base,
 			       _cairo_deflate_stream_write,
@@ -142,7 +140,7 @@ _cairo_deflate_stream_create (cairo_output_stream_t *output)
 
     if (deflateInit (&stream->zlib_stream, Z_DEFAULT_COMPRESSION) != Z_OK) {
 	free (stream);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
     }
 
     stream->zlib_stream.next_in = stream->input_buf;
diff --git a/src/cairo-output-stream-private.h b/src/cairo-output-stream-private.h
index edaabbe78..ea5b1da8f 100644
--- a/src/cairo-output-stream-private.h
+++ b/src/cairo-output-stream-private.h
@@ -63,8 +63,6 @@ struct _cairo_output_stream {
     cairo_bool_t		     closed;
 };
 
-extern const cairo_private cairo_output_stream_t _cairo_output_stream_nil;
-
 cairo_private void
 _cairo_output_stream_init (cairo_output_stream_t            *stream,
 			   cairo_output_stream_write_func_t  write_func,
diff --git a/src/cairo-output-stream.c b/src/cairo-output-stream.c
index 0adda365c..554214f9e 100644
--- a/src/cairo-output-stream.c
+++ b/src/cairo-output-stream.c
@@ -87,7 +87,7 @@ _cairo_output_stream_fini (cairo_output_stream_t *stream)
     return _cairo_output_stream_close (stream);
 }
 
-const cairo_output_stream_t _cairo_output_stream_nil = {
+static const cairo_output_stream_t _cairo_output_stream_nil = {
     NULL, /* write_func */
     NULL, /* flush_func */
     NULL, /* close_func */
@@ -147,10 +147,8 @@ _cairo_output_stream_create (cairo_write_func_t		write_func,
     cairo_output_stream_with_closure_t *stream;
 
     stream = malloc (sizeof (cairo_output_stream_with_closure_t));
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (&stream->base,
 			       closure_write, NULL, closure_close);
@@ -173,10 +171,8 @@ _cairo_output_stream_create_in_error (cairo_status_t status)
 	return (cairo_output_stream_t *) &_cairo_output_stream_nil_write_error;
 
     stream = malloc (sizeof (cairo_output_stream_t));
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (stream, NULL, NULL, NULL);
     stream->status = status;
@@ -592,16 +588,12 @@ _cairo_output_stream_create_for_file (FILE *file)
 {
     stdio_stream_t *stream;
 
-    if (file == NULL) {
-	_cairo_error_throw (CAIRO_STATUS_WRITE_ERROR);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil_write_error;
-    }
+    if (unlikely (file == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_WRITE_ERROR));
 
     stream = malloc (sizeof *stream);
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (&stream->base,
 			       stdio_write, stdio_flush, stdio_flush);
@@ -623,19 +615,16 @@ _cairo_output_stream_create_for_filename (const char *filename)
     if (file == NULL) {
 	switch (errno) {
 	case ENOMEM:
-	    _cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	    return (cairo_output_stream_t *) &_cairo_output_stream_nil;
+	    return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 	default:
-	    _cairo_error_throw (CAIRO_STATUS_WRITE_ERROR);
-	    return (cairo_output_stream_t *) &_cairo_output_stream_nil_write_error;
+	    return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_WRITE_ERROR));
 	}
     }
 
     stream = malloc (sizeof *stream);
     if (unlikely (stream == NULL)) {
 	fclose (file);
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
     }
 
     _cairo_output_stream_init (&stream->base,
@@ -676,10 +665,8 @@ _cairo_memory_stream_create (void)
     memory_stream_t *stream;
 
     stream = malloc (sizeof *stream);
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (&stream->base, memory_write, NULL, memory_close);
     _cairo_array_init (&stream->array, 1);
@@ -753,10 +740,8 @@ _cairo_null_stream_create (void)
     cairo_output_stream_t *stream;
 
     stream = malloc (sizeof *stream);
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (stream, null_write, NULL, NULL);
 
diff --git a/src/cairo-pdf-operators.c b/src/cairo-pdf-operators.c
index 58c647219..c4e4343b8 100644
--- a/src/cairo-pdf-operators.c
+++ b/src/cairo-pdf-operators.c
@@ -356,10 +356,8 @@ _word_wrap_stream_create (cairo_output_stream_t *output, int max_column)
 	return _cairo_output_stream_create_in_error (output->status);
 
     stream = malloc (sizeof (word_wrap_stream_t));
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (&stream->base,
 			       _word_wrap_stream_write,
diff --git a/src/cairo-ps-surface.c b/src/cairo-ps-surface.c
index 96f5bcf2c..2e4f52c03 100644
--- a/src/cairo-ps-surface.c
+++ b/src/cairo-ps-surface.c
@@ -1952,10 +1952,8 @@ _string_array_stream_create (cairo_output_stream_t *output)
     string_array_stream_t *stream;
 
     stream = malloc (sizeof (string_array_stream_t));
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (&stream->base,
 			       _string_array_stream_write,
@@ -1979,10 +1977,8 @@ _base85_array_stream_create (cairo_output_stream_t *output)
     string_array_stream_t *stream;
 
     stream = malloc (sizeof (string_array_stream_t));
-    if (unlikely (stream == NULL)) {
-	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
-	return (cairo_output_stream_t *) &_cairo_output_stream_nil;
-    }
+    if (unlikely (stream == NULL))
+	return _cairo_output_stream_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 
     _cairo_output_stream_init (&stream->base,
 			       _string_array_stream_write,