Add stream printing context.

This is some infrastructure which will support *print-circle*.

* lib.h (struct strm_ctx): Forward declared.
(struct cobj_ops): Add context parameter to print function
pointer.
(cobj_print_op, obj_print_impl): Add context parameter to
declarations.

* hash.c (hash_print_op): Take context argument and
pass it down in obj_print_impl calls.

* lib.c (cobj_print_op, out_quasi_str): Likewise
(obj_print_impl): Likewise, and also pass to
COBJ print method.
(obj_print, obj_pprint): Pass null pointer
as context argument to obj_print_impl.

* regex.c (regex_print): Take context parameter and ignore it.

* socket.c (dgram_print): Likewise.

* stream.h (struct strm_ctx): New struct type.
(struct strm_base): New ctx member, pointer to struct
strm_ctx.
(stream_print_op): Add context parameter to declaration.
(get_set_ctx, get_ctx): Declared.

* stream.c (strm_base_init): Add null pointer to initializer.
(strm_base_cleanup): Add assertion against context pointer
being non-null: that indicates that some stream operation
installed a context pointer and neglected to restore it to
null before returning, which is bad because context will be
stack allocated.
(stream_print_op, stdio_stream_print, cat_stream_print): Take
context parameter and ignore it.
(get_set_ctx, get_ctx): New functions.

* struct.c (struct_type_print): Take context parameter and
ignore it.
(struct_inst_print): Take context parameter and pass
down to obj_print_impl.

1 files changed, 26 insertions, 5 deletions

diff --git a/stream.c b/stream.c
index 0c7fa12b..3282b7f6 100644
--- a/stream.c
+++ b/stream.c
@@ -90,13 +90,13 @@ val shell, shell_arg;
 
 void strm_base_init(struct strm_base *s)
 {
-  static struct strm_base init = { indent_off, 60, 10, 0, 0 };
+  static struct strm_base init = { indent_off, 60, 10, 0, 0, 0 };
   *s = init;
 }
 
 void strm_base_cleanup(struct strm_base *s)
 {
-  (void) s;
+  bug_unless (s->ctx == 0);
 }
 
 void strm_base_mark(struct strm_base *s)
@@ -104,10 +104,11 @@ void strm_base_mark(struct strm_base *s)
   (void) s;
 }
 
-void stream_print_op(val stream, val out, val pretty)
+void stream_print_op(val stream, val out, val pretty, struct strm_ctx *ctx)
 {
   val name = stream_get_prop(stream, name_k);
   (void) pretty;
+  (void) ctx;
   format(out, lit("#<~a ~p>"), name, stream, nao);
 }
 
@@ -388,7 +389,8 @@ struct stdio_handle {
 #endif
 };
 
-static void stdio_stream_print(val stream, val out, val pretty)
+static void stdio_stream_print(val stream, val out, val pretty,
+                               struct strm_ctx *ctx)
 {
   struct stdio_handle *h = coerce(struct stdio_handle *, stream->co.handle);
   struct strm_ops *ops = coerce(struct strm_ops *, stream->co.ops);
@@ -396,6 +398,7 @@ static void stdio_stream_print(val stream, val out, val pretty)
   val descr = ops->get_prop(stream, name_k);
 
   (void) pretty;
+  (void) ctx;
 
   if (h->pid)
     format(out, lit("#<~a ~a ~a ~p>"), name, descr, num(h->pid), stream, nao);
@@ -2181,13 +2184,15 @@ struct cat_strm {
   val streams;
 };
 
-static void cat_stream_print(val stream, val out, val pretty)
+static void cat_stream_print(val stream, val out, val pretty,
+                             struct strm_ctx *ctx)
 {
   struct cat_strm *s = coerce(struct cat_strm *, stream->co.handle);
   struct strm_ops *ops = coerce(struct strm_ops *, stream->co.ops);
   val name = static_str(ops->name);
 
   (void) pretty;
+  (void) ctx;
 
   format(out, lit("#<~a ~s>"), name, s->streams, nao);
 }
@@ -3535,6 +3540,22 @@ val width_check(val stream, val alt)
   return t;
 }
 
+struct strm_ctx *get_set_ctx(val stream, struct strm_ctx *ctx)
+{
+  struct strm_base *s = coerce(struct strm_base *,
+                               cobj_handle(stream, stream_s));
+  struct strm_ctx *ret = s->ctx;
+  s->ctx = ctx;
+  return ret;
+}
+
+struct strm_ctx *get_ctx(val stream)
+{
+  struct strm_base *s = coerce(struct strm_base *,
+                               cobj_handle(stream, stream_s));
+  return s->ctx;
+}
+
 val get_string(val stream_in, val nchars, val close_after_p)
 {
   val stream = default_arg(stream_in, std_input);