From 9d4023b751919cdcca651198cfeda36a776f2c91 Mon Sep 17 00:00:00 2001
From: Morten Rolland <Morten.Rolland@asker.mail.telia.com>
Date: Wed, 6 Jan 1999 00:08:46 +0000
Subject: [PATCH] Extended module framework to enable demanding data from
 upstream modules.

---
 include/ifax/module.h | 18 +++++++++++++++++-
 lib/Makefile          |  2 +-
 lib/module.c          |  8 ++++++++
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/include/ifax/module.h b/include/ifax/module.h
index c6a1c3c..2ac93cc 100644
--- a/include/ifax/module.h
+++ b/include/ifax/module.h
@@ -27,6 +27,12 @@ typedef struct ifax_module {
 	 */
 	int 	(*handle_input)(struct ifax_module *self, void *data, size_t len);
 
+	/* This function is called to request data from the previous module
+	 * in the chain.  The resulting data is delivered by means of the
+	 * 'handle_input' method.
+	 */
+	void	(*handle_demand)(struct ifax_module *self, size_t len);
+
 	/* Use this to implement "commands" to modules like changing operating
 	 * parameters "on-the-fly".
 	 */
@@ -41,7 +47,13 @@ typedef struct ifax_module {
 	 * Some modules (like replicate.c) have their own ideas about that.
 	 */
 	struct ifax_module	*sendto;
-	
+
+	/* We need a reverse chain as well, to be able to request data from
+	 * from the previous module.  The 'replicate' module and similar
+	 * will have to know which chain to request data from.
+	 */
+	struct ifax_module	*recvfrom;
+
 } ifax_module;
 
 /* A module instance is identified by that handle type.
@@ -83,6 +95,10 @@ ifax_modp ifax_create_module(ifax_module_id what_kind,...);
  */
 int ifax_handle_input(struct ifax_module *self,void *data,size_t len);
 
+/* Request data from previous modules.
+ */
+void ifax_handle_demand(struct ifax_module *self, size_t len);
+
 /* Send a command to a module. Semantics are defined by the module.
  */
 int ifax_command(struct ifax_module *self, int command, ...);
diff --git a/lib/Makefile b/lib/Makefile
index 937e18e..b459928 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -10,4 +10,4 @@ isdnlib.a: $(LIBOBJS)
 	$(AR) rcs $@ $^
 
 clean:
-	rm -f $(LIBOBJS) *~
+	rm -f $(LIBOBJS) isdnlib.a *~
diff --git a/lib/module.c b/lib/module.c
index 9ff6023..e594796 100644
--- a/lib/module.c
+++ b/lib/module.c
@@ -100,6 +100,14 @@ int ifax_handle_input(struct ifax_module *self,void *data,size_t len)
 	return self->handle_input(self, data,len);
 }
 
+/* Request data from a module.  Length is specified by the module,
+ * just like the 'handle_input' method.
+ */
+void ifax_handle_demand(struct ifax_module *self, size_t len)
+{
+	self->handle_demand(self,len);
+}
+
 /* Send a command to a module. Note, that commands and data are defined 
  * by the module.
  */