lib_common: new class for module visibility

Add MODULE_FLAG_ALIAS (+ complete API) for modules that are not hidden
as technical/deprecated moudles but rather an alias.

The difference is important for GUI not to print aliased module twice.

Author: MartinPulec

src/lib_common.cpp

@@ -3,7 +3,7 @@
  * @author Martin Pulec     <[email protected]>
  */
 /*
- * Copyright (c) 2012-2023 CESNET, z. s. p. o.
+ * Copyright (c) 2012-2025 CESNET
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -215,7 +215,7 @@ void open_all(const char *pattern, list<void *> &libs) {
 struct lib_info {
         const void *data;
         int abi_version;
-        bool hidden;
+        unsigned visibility_flag;
 };
 
 // http://stackoverflow.com/questions/1801892/making-mapfind-operation-case-insensitive
@@ -247,13 +247,22 @@ static auto& get_libmap(){
         return libraries;
 }
 
-void register_library(const char *name, const void *data, enum library_class cls, int abi_version, int hidden)
+/**
+ * @param name             module name (used in listing and on cmdline for spec)
+ * @param cls              module class
+ * @param name             class-specific metadata structure (with callbacks)
+ * @param abi_version      class-specific ABI version
+ * @param visibility_flag  usually 0 or flag from @ref enum module_flag
+ */
+void
+register_library(const char *name, const void *info, enum library_class cls,
+                 int abi_version, unsigned visibility_flag)
 {
         auto& map = get_libmap()[cls];
         if (map.find(name) != map.end()) {
                 LOG(LOG_LEVEL_ERROR) << "Module \"" << name << "\" (class " << cls << ") multiple initialization!\n";
         }
-        map[name] = {data, abi_version, static_cast<bool>(hidden)};
+        map[name] = {info, abi_version, visibility_flag};
 }
 
 const void *load_library(const char *name, enum library_class cls, int abi_version)
@@ -293,10 +302,12 @@ const void *load_library(const char *name, enum library_class cls, int abi_versi
 
 /**
  * Prints list of modules of given class
- * @param full  include hidden modules
+ * @param full  include hidden modules and aliases
  */
 void list_modules(enum library_class cls, int abi_version, bool full) {
-        const auto & class_set = get_libraries_for_class(cls, abi_version, full);
+        const auto &class_set = get_libraries_for_class(
+            cls, abi_version,
+            full ? MODULE_SHOW_ALL : MODULE_SHOW_VISIBLE_ONLY);
         for (auto && item : class_set) {
                 col() << "\t" << SBOLD(item.first.c_str()) << "\n";
         }
@@ -333,15 +344,19 @@ bool list_all_modules() {
         return ret;
 }
 
-map<string, const void *> get_libraries_for_class(enum library_class cls, int abi_version, bool include_hidden)
+map<string, const void *>
+get_libraries_for_class(enum library_class cls, int abi_version,
+                        unsigned include_flags)
 {
         map<string, const void *> ret;
         auto& libraries = get_libmap();
         auto it = libraries.find(cls);
         if (it != libraries.end()) {
                 for (auto && item : it->second) {
                         if (abi_version == item.second.abi_version) {
-                                if (include_hidden || !item.second.hidden) {
+                                if (item.second.visibility_flag == 0 ||
+                                    (include_flags &
+                                     item.second.visibility_flag) != 0U) {
                                         ret[item.first] = item.second.data;
                                 }
                         } else {
@@ -354,4 +369,3 @@ map<string, const void *> get_libraries_for_class(enum library_class cls, int ab
 
         return ret;
 }
-

src/lib_common.h

@@ -3,7 +3,7 @@
  * @author Martin Pulec     <[email protected]>
  */
 /*
- * Copyright (c) 2011-2023 CESNET, z. s. p. o.
+ * Copyright (c) 2011-2025 CESNET
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -85,45 +85,59 @@ enum library_class {
         LIBRARY_CLASS_AUDIO_FILTER,
 };
 const void *load_library(const char *name, enum library_class, int abi_version);
-void register_library(const char *name, const void *info, enum library_class, int abi_version, int hidden);
+void register_library(const char *name, const void *info, enum library_class,
+                      int abi_version, unsigned visibility_flag);
 void list_modules(enum library_class, int abi_version, bool full);
 bool list_all_modules();
 #ifdef __cplusplus
 }
 #endif
 
+enum module_flag {
+        MODULE_SHOW_VISIBLE_ONLY = 0,      ///< display only modules w/o flag
+        MODULE_FLAG_HIDDEN       = 1 << 0, ///< flag - do not show in listing
+        MODULE_FLAG_ALIAS =
+            1 << 1, ///< ditto + hide for GUI, for explicit init only
+        MODULE_SHOW_ALL =
+            MODULE_FLAG_HIDDEN | MODULE_FLAG_ALIAS, ///< display all modules
+};
+
 #ifdef __cplusplus
 #include <map>
 #include <string>
-std::map<std::string, const void *> get_libraries_for_class(enum library_class cls, int abi_version, bool include_hidden = true);
+std::map<std::string, const void *>
+get_libraries_for_class(enum library_class cls, int abi_version,
+                        unsigned include_flags = MODULE_FLAG_HIDDEN);
 #endif
 
 /**
  * Placeholder that installs module via constructor for every macro
- * REGISTER_MODULE/REGISTER_MODULE_HIDDEN call
+ * REGISTER_MODULE* call
  * @param name     non-quoted module name
  * @param lclass   class of the module
  * @param abi      abi version (specific for every class)
  * @param funcname unique function name that will be used to register
  *                 the module (as a constructor)
- * @param hidden   0/1 - whether the module should be visible by eg. '-c help'
- *                 (for technical and deprecated modules), default true
+ * @param flag     optional flag to limit visibility (@ref module_flag;
+ *                 for technical, deprecated modules and aliases), default 0
  */
-#define REGISTER_MODULE_FUNCNAME(name, info, lclass, abi, funcname, hidden) static void funcname(void)  __attribute__((constructor));\
+#define REGISTER_MODULE_FUNCNAME(name, info, lclass, abi, funcname, flag) \
+        static void funcname(void) __attribute__((constructor)); \
 \
 static void funcname(void)\
 {\
-        register_library(#name, info, lclass, abi, hidden);\
+        register_library(#name, info, lclass, abi, flag);\
 }\
 struct NOT_DEFINED_STRUCT_THAT_SWALLOWS_SEMICOLON
 
-#define REGISTER_MODULE_FUNC_FUNCNAME(name, func, lclass, abi, funcname, hidden) static void funcname(void)  __attribute__((constructor));\
+#define REGISTER_MODULE_FUNC_FUNCNAME(name, func, lclass, abi, funcname, flag) \
+        static void funcname(void) __attribute__((constructor)); \
 \
 static void funcname(void)\
 {\
         const void *info = func();\
         if (info) {\
-                register_library(#name, info, lclass, abi, hidden);\
+                register_library(#name, info, lclass, abi, flag);\
         }\
 }\
 struct NOT_DEFINED_STRUCT_THAT_SWALLOWS_SEMICOLON
@@ -150,10 +164,11 @@ struct NOT_DEFINED_STRUCT_THAT_SWALLOWS_SEMICOLON
 #define REGISTER_MODULE_WITH_FUNC(name, func, lclass, abi) REGISTER_MODULE_FUNC_FUNCNAME(name, func, lclass, abi, UNIQUE_LABEL, 0)
 
 /**
- * Similar to @ref REGISTER_MODULE but do not show the module under help
- * of corresponding class (usable for technical or deprecated modules).
+ * Similar to @ref REGISTER_MODULE but allow @ref module_flag to be added to limit visibility.
  */
-#define REGISTER_HIDDEN_MODULE(name, info, lclass, abi) REGISTER_MODULE_FUNCNAME(name, info, lclass, abi, UNIQUE_LABEL, 1)
+#define REGISTER_MODULE_WITH_FLAG(name, info, lclass, abi, flag) \
+        REGISTER_MODULE_FUNCNAME(name, info, lclass, abi, UNIQUE_LABEL, flag)
+#define REGISTER_HIDDEN_MODULE(name, info, lclass, abi) REGISTER_MODULE_WITH_FLAG(name, info, lclass, abi, MODULE_FLAG_HIDDEN)
 
 #endif // defined LIB_COMMON_H