From 9c334cc6a6685201ffe912655d701321976d1cfd Mon Sep 17 00:00:00 2001
From: Sebastian Ramacher <s.ramacher@gmx.at>
Date: Wed, 21 Mar 2012 16:23:29 +0100
Subject: [PATCH] Add ABI versioning.

---
 Makefile     |  4 +++-
 config.mk    |  3 +++
 document.c   | 30 +++++++++++++++++++++++++++++-
 document.h   | 10 ++++++++++
 version.h.in |  1 +
 5 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index d62a71d..1cf8093 100644
--- a/Makefile
+++ b/Makefile
@@ -43,7 +43,8 @@ version.h: version.h.in config.mk
 	$(QUIET)sed 's/ZVMAJOR/${ZATHURA_VERSION_MAJOR}/' < version.h.in | \
 		sed 's/ZVMINOR/${ZATHURA_VERSION_MINOR}/' | \
 		sed 's/ZVREV/${ZATHURA_VERSION_REV}/' | \
-		sed 's/ZVAPI/${ZATHURA_API_VERSION}/' > version.h
+		sed 's/ZVAPI/${ZATHURA_API_VERSION}/' | \
+		sed 's/ZVABI/${ZATHURA_ABI_VERSION}/' > version.h
 
 %.o: %.c
 	$(ECHO) CC $<
@@ -80,6 +81,7 @@ ${PROJECT}.pc: ${PROJECT}.pc.in config.mk
 	$(QUIET)echo project=${PROJECT} > ${PROJECT}.pc
 	$(QUIET)echo version=${VERSION} >> ${PROJECT}.pc
 	$(QUIET)echo apiversion=${ZATHURA_API_VERSION} >> ${PROJECT}.pc
+	$(QUIET)echo abiversion=${ZATHURA_ABI_VERSION} >> ${PROJECT}.pc
 	$(QUIET)echo includedir=${INCLUDEDIR} >> ${PROJECT}.pc
 	$(QUIET)echo plugindir=${PLUGINDIR} >> ${PROJECT}.pc
 	$(QUIET)echo GTK_VERSION=${ZATHURA_GTK_VERSION} >> ${PROJECT}.pc
diff --git a/config.mk b/config.mk
index d5535dd..921c1f7 100644
--- a/config.mk
+++ b/config.mk
@@ -4,7 +4,10 @@
 ZATHURA_VERSION_MAJOR = 0
 ZATHURA_VERSION_MINOR = 1
 ZATHURA_VERSION_REV = 1
+# If the API changes, the API version and the ABI version have to be bumped.
 ZATHURA_API_VERSION = 1
+# If the ABI breaks for any reason, this has to be bumped.
+ZATHURA_ABI_VERSION = 1
 VERSION = ${ZATHURA_VERSION_MAJOR}.${ZATHURA_VERSION_MINOR}.${ZATHURA_VERSION_REV}
 
 # the GTK+ version to use
diff --git a/document.c b/document.c
index 8bf8ea7..263b90a 100644
--- a/document.c
+++ b/document.c
@@ -63,7 +63,7 @@ zathura_document_plugins_load(zathura_t* zathura)
         continue;
       }
 
-      /* resolve symbol and check API version*/
+      /* resolve symbols and check API and ABI version*/
       zathura_plugin_api_version_t api_version;
       *(void**)(&api_version) = dlsym(handle, PLUGIN_API_VERSION_FUNCTION);
       if (api_version != NULL) {
@@ -75,7 +75,35 @@ zathura_document_plugins_load(zathura_t* zathura)
           continue;
         }
       } else {
+#if ZATHURA_API_VERSION == 1
         girara_warning("could not find '%s' function in plugin %s ... loading anyway", PLUGIN_API_VERSION_FUNCTION, path);
+#else
+        girara_error("could not find '%s' function in plugin %s", PLUGIN_API_VERSION_FUNCTION, path);
+        g_free(path);
+        dlclose(handle);
+        continue;
+#endif
+      }
+
+      zathura_plugin_abi_version_t abi_version;
+      *(void**)(&abi_version) = dlsym(handle, PLUGIN_ABI_VERSION_FUNCTION);
+      if (abi_version != NULL) {
+        if (abi_version() != ZATHURA_ABI_VERSION) {
+          girara_error("plugin %s has been built againt zathura with a different ABI version (plugin: %d, zathura: %d)",
+              path, abi_version(), ZATHURA_ABI_VERSION);
+          g_free(path);
+          dlclose(handle);
+          continue;
+        }
+      } else {
+#if ZATHURA_API_VERSION == 1
+        girara_warning("could not find '%s' function in plugin %s ... loading anyway", PLUGIN_ABI_VERSION_FUNCTION, path);
+#else
+        girara_error("could not find '%s' function in plugin %s", PLUGIN_ABI_VERSION_FUNCTION, path);
+        g_free(path);
+        dlclose(handle);
+        continue;
+#endif
       }
 
       zathura_plugin_register_service_t register_plugin;
diff --git a/document.h b/document.h
index b6d4f01..398191c 100644
--- a/document.h
+++ b/document.h
@@ -13,6 +13,7 @@
 
 #define PLUGIN_REGISTER_FUNCTION "plugin_register"
 #define PLUGIN_API_VERSION_FUNCTION "plugin_api_version"
+#define PLUGIN_ABI_VERSION_FUNCTION "plugin_abi_version"
 
 /**
  * Register a plugin.
@@ -29,6 +30,7 @@
   unsigned int plugin_version_minor() { return minor; } \
   unsigned int plugin_version_revision() { return rev; } \
   unsigned int plugin_api_version() { return ZATHURA_API_VERSION; } \
+  unsigned int plugin_abi_version() { return ZATHURA_ABI_VERSION; } \
   \
   void plugin_register(zathura_document_plugin_t* plugin) \
   { \
@@ -119,6 +121,14 @@ typedef void (*zathura_plugin_register_service_t)(zathura_document_plugin_t*);
  */
 typedef unsigned int (*zathura_plugin_api_version_t)();
 
+/**
+ * Function prototype that is called to get the ABI version the plugin is built
+ * against.
+ *
+ * @return plugin's ABI version
+ */
+typedef unsigned int (*zathura_plugin_abi_version_t)();
+
 /**
  * Image buffer
  */
diff --git a/version.h.in b/version.h.in
index 891eb47..91fbe70 100644
--- a/version.h.in
+++ b/version.h.in
@@ -8,5 +8,6 @@
 #define ZATHURA_VERSION_REV ZVREV
 #define ZATHURA_VERSION "ZVMAJOR.ZVMINOR.ZVREV"
 #define ZATHURA_API_VERSION ZVAPI
+#define ZATHURA_ABI_VERSION ZVABI
 
 #endif