From 162375842bbeaa3e248f406aa03e242a9490b6ec Mon Sep 17 00:00:00 2001
From: Enno Rehling <enno.rehling@gmail.com>
Date: Thu, 3 Jul 2014 05:10:53 -0700
Subject: [PATCH] introducing new callback system

---
 src/CMakeLists.txt  |  2 ++
 src/callback.c      | 54 +++++++++++++++++++++++++++++++++++++++++++++
 src/callback.h      | 16 ++++++++++++++
 src/callback.test.c | 50 +++++++++++++++++++++++++++++++++++++++++
 src/test_eressea.c  |  2 ++
 5 files changed, 124 insertions(+)
 create mode 100644 src/callback.c
 create mode 100644 src/callback.h
 create mode 100644 src/callback.test.c

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index f2faa2bc4..fb1ccc8ef 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -59,6 +59,7 @@ ENDIF()
 
 set (ERESSEA_SRC
   eressea.c
+  callback.c
   direction.c
   keyword.c
   skill.c
@@ -146,6 +147,7 @@ set(TESTS_SRC
   test_eressea.c
   tests.c
   tests.test.c
+  callback.test.c
   direction.test.c
   keyword.test.c
   skill.test.c
diff --git a/src/callback.c b/src/callback.c
new file mode 100644
index 000000000..3813c6456
--- /dev/null
+++ b/src/callback.c
@@ -0,0 +1,54 @@
+#include "callback.h"
+#include <stdlib.h>
+#include <string.h>
+
+static struct reg {
+    struct reg * next;
+    CALLBACK cb;
+    const char *name;
+} *registry;
+
+CALLBACK create_callback(void (*cbv)(va_list va)) {
+    CALLBACK cb;
+    cb.cbv = cbv;
+    return cb;
+}
+
+void reset_callbacks(void) {
+    registry = 0;
+}
+
+CALLBACK register_callback(const char *name, void (*cbv)(va_list va))
+{
+    struct reg * r = (struct reg *)malloc(sizeof(struct reg));
+    r->next = registry;
+    r->name = name;
+    r->cb.cbv = cbv;
+    registry = r;
+    return r->cb;
+}
+
+int find_callback(const char *name, CALLBACK *result) {
+    if (result && name) {
+        struct reg *r;
+        for (r=registry;r;r=r->next) {
+            if (strcmp(r->name, name)==0) {
+                *result = r->cb;
+                return 0;
+            }
+        }
+    }
+    return -1;
+}
+
+int call_callback(CALLBACK cb, const char *name, ... ) {
+    va_list ap;
+    if (name) {
+        int err = find_callback(name, &cb);
+        if (err) return err;
+    }
+    va_start(ap, name);
+    cb.cbv(ap);
+    va_end(ap);
+    return 0;
+}
diff --git a/src/callback.h b/src/callback.h
new file mode 100644
index 000000000..b7f592161
--- /dev/null
+++ b/src/callback.h
@@ -0,0 +1,16 @@
+#ifndef H_CALLBACK_H
+#define H_CALLBACK_H
+
+#include <stdarg.h>
+
+typedef struct {
+    void (*cbv)(va_list va);
+} CALLBACK;
+
+CALLBACK register_callback(const char *name, void (*cbv)(va_list va));
+CALLBACK create_callback(void (*cbv)(va_list va));
+int find_callback(const char *name, CALLBACK *result);
+int call_callback(CALLBACK cb, const char *name, ...);
+void reset_callbacks(void);
+
+#endif
diff --git a/src/callback.test.c b/src/callback.test.c
new file mode 100644
index 000000000..b5fcba34b
--- /dev/null
+++ b/src/callback.test.c
@@ -0,0 +1,50 @@
+#include "callback.h"
+#include <stdlib.h>
+#include <CuTest.h>
+
+void callback(va_list ap) {
+    int i = (int)va_arg(ap, int);
+    int *p = va_arg(ap, int *);
+    *p += i;
+}
+
+static void test_find_callback(CuTest *tc) {
+    CALLBACK cb;
+    reset_callbacks();
+    CuAssertIntEquals(tc, -1, find_callback("test", &cb));
+    cb = register_callback("test", callback);
+    CuAssertIntEquals(tc, 0, find_callback("test", &cb));
+    reset_callbacks();
+}
+
+static void test_call_by_handle(CuTest *tc) {
+    CALLBACK cb;
+    int x = 0;
+    reset_callbacks();
+    cb = create_callback(callback);
+    CuAssertIntEquals(tc, 0, call_callback(cb, 0, 42, &x));
+    CuAssertIntEquals(tc, 42, x);
+    reset_callbacks();
+}
+
+static void test_call_by_name(CuTest *tc) {
+    CALLBACK cb, ca;
+    int x = 0;
+    reset_callbacks();
+    CuAssertIntEquals(tc, -1, call_callback(cb, "test", 42, &x));
+    cb = register_callback("test", callback);
+    CuAssertIntEquals(tc, 0, call_callback(cb, "test", 42, &x));
+    CuAssertIntEquals(tc, 42, x);
+    CuAssertIntEquals(tc, 0, call_callback(ca, "test", 42, &x));
+    CuAssertIntEquals(tc, 84, x);
+    reset_callbacks();
+}
+
+CuSuite *get_callback_suite(void)
+{
+  CuSuite *suite = CuSuiteNew();
+  SUITE_ADD_TEST(suite, test_find_callback);
+  SUITE_ADD_TEST(suite, test_call_by_name);
+  SUITE_ADD_TEST(suite, test_call_by_handle);
+  return suite;
+}
diff --git a/src/test_eressea.c b/src/test_eressea.c
index 00508bb9c..2b0fbee53 100644
--- a/src/test_eressea.c
+++ b/src/test_eressea.c
@@ -3,6 +3,7 @@
 #include <util/log.h>
 
 CuSuite *get_tests_suite(void);
+CuSuite *get_callback_suite(void);
 CuSuite *get_jsonconf_suite(void);
 CuSuite *get_json_suite(void);
 CuSuite *get_economy_suite(void);
@@ -41,6 +42,7 @@ int RunAllTests(void)
 
   /* self-test */
   CuSuiteAddSuite(suite, get_tests_suite());
+  CuSuiteAddSuite(suite, get_callback_suite());
   CuSuiteAddSuite(suite, get_json_suite());
   CuSuiteAddSuite(suite, get_jsonconf_suite());
   CuSuiteAddSuite(suite, get_direction_suite());