[new-backend] spec hook

doc/news/_preparation_next_release.md

@@ -59,6 +59,11 @@ The following section lists news about the [plugins](https://www.libelektra.org/
 - <<TODO>>
 - <<TODO>>
 
+### spec
+
+- Partial rewrite for spec hook _(Maximilian Irlinger @atmaxinger)_
+- <<TODO>>
+
 ### <<Plugin3>>
 
 - <<TODO>>

src/include/kdbprivate.h

@@ -101,6 +101,9 @@ typedef int (*kdbCommitPtr) (Plugin * handle, KeySet * returned, Key * parentKey
 
 typedef int (*kdbHookGoptsGetPtr) (Plugin * handle, KeySet * returned, Key * parentKey);
 
+typedef int (*kdbHookSpecCopyPtr) (Plugin * handle, KeySet * returned, Key * parentKey, bool isKdbGet);
+typedef int (*kdbHookSpecRemovePtr) (Plugin * handle, KeySet * returned, Key * parentKey);
+
 typedef Plugin * (*OpenMapper) (const char *, const char *, KeySet *);
 typedef int (*CloseMapper) (Plugin *);
 
@@ -321,8 +324,6 @@ struct _KeySet
 #endif
 };
 
-typedef struct _Hooks Hooks;
-
 /**
  * The access point to the key database.
  *
@@ -371,9 +372,16 @@ struct _KDB
 	{
 		struct
 		{
-			struct _Plugin* plugin;
-			kdbHookGoptsGetPtr kdbHookGoptsGet;
+			struct _Plugin * plugin;
+			kdbHookGoptsGetPtr get;
 		} gopts;
+
+		struct
+		{
+			struct _Plugin * plugin;
+			kdbHookSpecCopyPtr copy;
+			kdbHookSpecRemovePtr remove;
+		} spec;
 	} hooks;
 };
 

src/libs/elektra/hooks.c

@@ -19,6 +19,16 @@ void freeHooks (KDB * kdb, Key * errorKey)
 	if (kdb->hooks.gopts.plugin != NULL)
 	{
 		elektraPluginClose (kdb->hooks.gopts.plugin, errorKey);
+		kdb->hooks.gopts.plugin = NULL;
+		kdb->hooks.gopts.get = NULL;
+	}
+
+	if (kdb->hooks.spec.plugin != NULL)
+	{
+		elektraPluginClose (kdb->hooks.spec.plugin, errorKey);
+		kdb->hooks.spec.plugin = NULL;
+		kdb->hooks.spec.copy = NULL;
+		kdb->hooks.spec.remove = NULL;
 	}
 }
 
@@ -43,7 +53,27 @@ static int initHooksGopts (KDB * kdb, Plugin * plugin, Key * errorKey)
 
 	kdb->hooks.gopts.plugin = plugin;
 
-	if ((kdb->hooks.gopts.kdbHookGoptsGet = (kdbHookGoptsGetPtr) getFunction (plugin, "hook/gopts/get", errorKey)) == NULL)
+	if ((kdb->hooks.gopts.get = (kdbHookGoptsGetPtr) getFunction (plugin, "hook/gopts/get", errorKey)) == NULL)
+	{
+		return -1;
+	}
+
+	return 0;
+}
+
+static int initHooksSpec (KDB * kdb, Plugin * plugin, Key * errorKey)
+{
+	if (!plugin)
+	{
+		return -1;
+	}
+
+	kdb->hooks.spec.plugin = plugin;
+
+	kdb->hooks.spec.copy = (kdbHookSpecCopyPtr) getFunction (plugin, "hook/spec/copy", errorKey);
+	kdb->hooks.spec.remove = (kdbHookSpecRemovePtr) getFunction (plugin, "hook/spec/remove", errorKey);
+
+	if (kdb->hooks.spec.copy == NULL || kdb->hooks.spec.remove == NULL)
 	{
 		return -1;
 	}
@@ -138,6 +168,13 @@ static bool isGoptsEnabledByContract (const KeySet * contract)
 	return isEnabled;
 }
 
+static bool isSpecEnabledByConfig (const KeySet * config)
+{
+	// TODO: check for system:/elektra/hook/spec/enabled or system:/elektra/hook/spec/disabled or something else ... TBD
+	//       See this discussion: https://github.com/ElektraInitiative/libelektra/issues/4499
+	return true;
+}
+
 /**
  * Initializes the hooks stored in the passed KDB handle.
  * If the handle already contains initialized hooks, they will be reinitialized, including unloading and loading of their plugins.
@@ -169,6 +206,12 @@ int initHooks (KDB * kdb, const KeySet * config, KeySet * modules, const KeySet
 		goto error;
 	}
 
+	if (isSpecEnabledByConfig (config) &&
+	    initHooksSpec (kdb, loadPlugin ("spec", kdb->global, modules, contract, errorKey), errorKey) != 0)
+	{
+		goto error;
+	}
+
 	if (!existingError)
 	{
 		// remove dummy error again

src/libs/elektra/kdb.c

@@ -1865,28 +1865,30 @@ int kdbGet (KDB * handle, KeySet * ks, Key * parentKey)
 		goto error;
 	}
 
-	/* TODO (kodebach): implement actual steps with new global plugins
-		// Step 14: run spec plugin
-		if (!specGet (dataKs, cascadingParent))
-		{
-			clear_bit (parentKey->flags, KEY_LOCK_NAME | KEY_LOCK_VALUE);
-			goto error;
-		}
-		clear_bit (parentKey->flags, KEY_LOCK_NAME | KEY_LOCK_VALUE);
-	*/
-
 	// Step 13: run gopts (if enabled)
 	keyCopy (parentKey, initialParent, KEY_CP_NAME);
 	keySetNamespace (parentKey, KEY_NS_CASCADING);
 
-	if (goptsActive && !handle->hooks.gopts.kdbHookGoptsGet (handle->hooks.gopts.plugin, dataKs, parentKey))
+	if (goptsActive && !handle->hooks.gopts.get (handle->hooks.gopts.plugin, dataKs, parentKey))
 	{
 		clear_bit (parentKey->flags, KEY_LOCK_NAME | KEY_LOCK_VALUE);
 		goto error;
 	}
 
 	keySetNamespace (parentKey, keyGetNamespace (initialParent));
 
+	// Step 14: run spec plugin
+	if (handle->hooks.spec.plugin && handle->hooks.spec.copy (handle->hooks.spec.plugin, dataKs, parentKey, true) == -1)
+	{
+		clear_bit (parentKey->flags, KEY_LOCK_NAME | KEY_LOCK_VALUE);
+		goto error;
+	}
+	clear_bit (parentKey->flags, KEY_LOCK_NAME | KEY_LOCK_VALUE);
+
+	// TODO (atmaxinger): should we have a default:/ backend?
+	Key * defaultCutpoint = keyNew ("default:/", KEY_END);
+	KeySet * defaults = ksCut (dataKs, defaultCutpoint);
+
 	// Step 15: split dataKs for poststorage phase
 	// FIXME (kodebach): handle proc:/ keys
 	if (!backendsDivide (backends, dataKs))
@@ -1917,6 +1919,11 @@ int kdbGet (KDB * handle, KeySet * ks, Key * parentKey)
 	// Step 18: merge data into ks and return
 	backendsMerge (backends, ks);
 
+	// TODO (atmaxinger): should we have a default:/ backend?
+	ksAppend (ks, defaults);
+	ksDel (defaults);
+	keyDel (defaultCutpoint);
+
 	// Step 19: update cache
 	// FIXME (kodebach): implement cache
 
@@ -2320,6 +2327,11 @@ int kdbSet (KDB * handle, KeySet * ks, Key * parentKey)
 		goto error;
 	}
 
+	if (handle->hooks.spec.plugin && handle->hooks.spec.copy (handle->hooks.spec.plugin, ks, parentKey, false) == -1)
+	{
+		goto error;
+	}
+
 	// TODO (kodebach) [opt]: merge steps 4-6
 	// By merging steps 4-6, we MAY be able to avoid copying keys from unchanged and read-only backends.
 
@@ -2407,6 +2419,25 @@ int kdbSet (KDB * handle, KeySet * ks, Key * parentKey)
 		}
 	*/
 
+	// Step 8: merge data from all backends (for spec removal)
+	ksClear (setKs);
+	backendsMerge (backends, setKs);
+
+	// Step 9: run the spec plugin to remove copied metadata
+	if (handle->hooks.spec.plugin && handle->hooks.spec.remove (handle->hooks.spec.plugin, setKs, parentKey) == -1)
+	{
+		goto rollback;
+	}
+
+	// Step 10: split setKs for remaining phases
+	if (!backendsDivide (backends, setKs))
+	{
+		ELEKTRA_SET_INTERNAL_ERROR (parentKey,
+					    "Couldn't divide keys into mountpoints after spec removal. Please report this bug at "
+					    "https://issues.libelektra.org.");
+		goto rollback;
+	}
+
 	// Step 11a: run storage phase
 	if (!runSetPhase (backends, parentKey, KDB_SET_PHASE_STORAGE, false, KDB_SET_FN_SET))
 	{

src/plugins/spec/README.md

@@ -3,7 +3,6 @@
 - infos/licence = BSD
 - infos/needs =
 - infos/provides = check apply
-- infos/placements = postgetstorage presetstorage
 - infos/status = recommended productive nodep configurable global unfinished
 - infos/description = allows to give specifications for keys