| 1 | /* This file is part of the Linux Trace Toolkit viewer |
| 2 | * Copyright (C) 2003-2004 Michel Dagenais |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License Version 2 as |
| 6 | * published by the Free Software Foundation; |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | * GNU General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public License |
| 14 | * along with this program; if not, write to the Free Software |
| 15 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 16 | * MA 02111-1307, USA. |
| 17 | */ |
| 18 | |
| 19 | #ifndef MODULES_H |
| 20 | #define MODULES_H |
| 21 | |
| 22 | #include <glib.h> |
| 23 | |
| 24 | /* A module contains some functionality which becomes available atfer it is |
| 25 | initialized and before it is destroyed. A module is characterized by a name, |
| 26 | a description (short and long), a list of names of other modules on which |
| 27 | it depends, and an initialization and a destruction function. |
| 28 | |
| 29 | A library contains one or more modules and may be loaded dynamically. |
| 30 | The modules contained in a library are automatically registered through |
| 31 | constructors which are called when the library is loaded. For modules |
| 32 | directly linked with the main program (builtin), the constructors are |
| 33 | called before the main program starts. (However, neither malloc nor glib |
| 34 | functions are used during the registration process). |
| 35 | |
| 36 | The library loading path is a set of directories, where requested |
| 37 | libraries and modules are searched for. |
| 38 | */ |
| 39 | |
| 40 | typedef struct _LttvModule LttvModule; |
| 41 | |
| 42 | typedef struct _LttvLibrary LttvLibrary; |
| 43 | |
| 44 | typedef void (*LttvModuleInit)(); |
| 45 | |
| 46 | typedef void (*LttvModuleDestroy)(); |
| 47 | |
| 48 | typedef struct _LttvModuleInfo |
| 49 | { |
| 50 | char *name; |
| 51 | char *short_description; |
| 52 | char *description; |
| 53 | LttvModuleInit init; |
| 54 | LttvModuleDestroy destroy; |
| 55 | LttvLibrary *library; |
| 56 | unsigned require_count; |
| 57 | unsigned use_count; |
| 58 | unsigned prerequisites_number; |
| 59 | } LttvModuleInfo; |
| 60 | |
| 61 | |
| 62 | typedef struct _LttvLibraryInfo |
| 63 | { |
| 64 | char *name; |
| 65 | char *path; |
| 66 | unsigned load_count; |
| 67 | } LttvLibraryInfo; |
| 68 | |
| 69 | |
| 70 | typedef enum _LttvModuleError |
| 71 | { |
| 72 | LTTV_MODULE_NOT_FOUND, |
| 73 | LTTV_MODULE_NO_INIT |
| 74 | } LttvModuleError; |
| 75 | |
| 76 | |
| 77 | /* Insure that a module is loaded and initialized. Require count |
| 78 | (number of times the module was required) and use count |
| 79 | (number of times required or used as prerequisite) serve to |
| 80 | insure that a module is destroyed only after it has been released |
| 81 | as many times as it was required (and prerequired). |
| 82 | |
| 83 | The module is searched among the modules currently loaded, then as a |
| 84 | similarly named library to load which should contain the named module. |
| 85 | If the module cannot be found or loaded, NULL is returned and an |
| 86 | explanation is provided in error. */ |
| 87 | |
| 88 | LttvModule *lttv_module_require(char *name, GError **error); |
| 89 | |
| 90 | void lttv_module_release(LttvModule *m); |
| 91 | |
| 92 | |
| 93 | /* Obtain information about the module, including the containing library */ |
| 94 | |
| 95 | void lttv_module_info(LttvModule *m, LttvModuleInfo *info); |
| 96 | |
| 97 | |
| 98 | /* List the modules on which this module depends */ |
| 99 | |
| 100 | unsigned lttv_module_prerequisite_number(LttvModule *m); |
| 101 | |
| 102 | LttvModule *lttv_module_prerequisite_get(LttvModule *m, unsigned i); |
| 103 | |
| 104 | |
| 105 | /* Insure that a library is loaded. A load count insures that a library |
| 106 | is unloaded only after it has been asked to unload as |
| 107 | many times as it was loaded, and its modules are not in use. The library |
| 108 | is searched along the library path if name is a relative pathname. |
| 109 | If the library cannot be found or loaded, NULL is returned and an |
| 110 | explanation is provided in error. */ |
| 111 | |
| 112 | LttvLibrary *lttv_library_load(char *name, GError **error); |
| 113 | |
| 114 | /* Returns 0 if library is unloaded, > 0 otherwise */ |
| 115 | gint lttv_library_unload(LttvLibrary *l); |
| 116 | |
| 117 | |
| 118 | /* Obtain information about the library */ |
| 119 | |
| 120 | void lttv_library_info(LttvLibrary *l, LttvLibraryInfo *info); |
| 121 | |
| 122 | |
| 123 | /* List the modules contained in a library */ |
| 124 | |
| 125 | unsigned lttv_library_module_number(LttvLibrary *l); |
| 126 | |
| 127 | LttvModule *lttv_library_module_get(LttvLibrary *l, unsigned i); |
| 128 | |
| 129 | |
| 130 | /* List the currently loaded libraries */ |
| 131 | |
| 132 | unsigned lttv_library_number(); |
| 133 | |
| 134 | LttvLibrary *lttv_library_get(unsigned i); |
| 135 | |
| 136 | |
| 137 | |
| 138 | /* Add or remove directory names to the library search path */ |
| 139 | |
| 140 | void lttv_library_path_add(const char *name); |
| 141 | |
| 142 | void lttv_library_path_remove(const char *name); |
| 143 | |
| 144 | |
| 145 | /* List the directory names in the library search path */ |
| 146 | |
| 147 | unsigned lttv_library_path_number(); |
| 148 | |
| 149 | char *lttv_library_path_get(unsigned i); |
| 150 | |
| 151 | |
| 152 | /* To define a module, simply call the LTTV_MODULE macro with the needed |
| 153 | arguments: single word name, one line short description, larger |
| 154 | description, initialization function, destruction function, and |
| 155 | list of names for required modules (e.g., "moduleA", "moduleB"). |
| 156 | This will insure that the module is registered at library load time. |
| 157 | |
| 158 | Example: |
| 159 | |
| 160 | LTTV_MODULE("option", "Command line options processing", "...", \ |
| 161 | init, destroy, "moduleA", "moduleB") |
| 162 | */ |
| 163 | |
| 164 | #define LTTV_MODULE(name, short_desc, desc, init, destroy, ...) \ |
| 165 | \ |
| 166 | static void _LTTV_MODULE_REGISTER(__LINE__)() \ |
| 167 | __attribute__((constructor)); \ |
| 168 | \ |
| 169 | static void _LTTV_MODULE_REGISTER(__LINE__)() \ |
| 170 | { \ |
| 171 | static char *module_prerequisites[] = { __VA_ARGS__ }; \ |
| 172 | \ |
| 173 | static struct _LttvModuleDescription module = { \ |
| 174 | name, short_desc, desc, init, destroy, \ |
| 175 | sizeof(module_prerequisites) / sizeof(char *), \ |
| 176 | module_prerequisites, NULL}; \ |
| 177 | \ |
| 178 | lttv_module_register(&module); \ |
| 179 | } |
| 180 | |
| 181 | |
| 182 | /* Internal structure and function used to register modules, called by |
| 183 | LTTV_MODULE */ |
| 184 | |
| 185 | #define __LTTV_MODULE_REGISTER(line) _lttv_module_register_ ## line |
| 186 | #define _LTTV_MODULE_REGISTER(line) __LTTV_MODULE_REGISTER(line) |
| 187 | |
| 188 | struct _LttvModuleDescription |
| 189 | { |
| 190 | char *name; |
| 191 | char *short_description; |
| 192 | char *description; |
| 193 | LttvModuleInit init; |
| 194 | LttvModuleDestroy destroy; |
| 195 | unsigned prerequisites_number; |
| 196 | char **prerequisites; |
| 197 | struct _LttvModuleDescription *next; |
| 198 | }; |
| 199 | |
| 200 | void lttv_module_register(struct _LttvModuleDescription *d); |
| 201 | |
| 202 | #endif // MODULES_H |
| 203 | |
| 204 | |
| 205 | |
| 206 | |
| 207 | |
| 208 | |