1 // Copyright (C) 2016 and later: Unicode, Inc. and others. 2 // License & terms of use: http://www.unicode.org/copyright.html 3 /* 4 ****************************************************************************** 5 * 6 * Copyright (C) 2009-2015, International Business Machines 7 * Corporation and others. All Rights Reserved. 8 * 9 ****************************************************************************** 10 * 11 * FILE NAME : icuplug.h 12 * 13 * Date Name Description 14 * 10/29/2009 sl New. 15 ****************************************************************************** 16 */ 17 18 /** 19 * \file 20 * \brief C API: ICU Plugin API 21 * 22 * <h2>C API: ICU Plugin API</h2> 23 * 24 * <p>C API allowing run-time loadable modules that extend or modify ICU functionality.</p> 25 * 26 * <h3>Loading and Configuration</h3> 27 * 28 * <p>At ICU startup time, the environment variable "ICU_PLUGINS" will be 29 * queried for a directory name. If it is not set, the preprocessor symbol 30 * "DEFAULT_ICU_PLUGINS" will be checked for a default value.</p> 31 * 32 * <p>Within the above-named directory, the file "icuplugins##.txt" will be 33 * opened, if present, where ## is the major+minor number of the currently 34 * running ICU (such as, 44 for ICU 4.4, thus icuplugins44.txt)</p> 35 * 36 * <p>The configuration file has this format:</p> 37 * 38 * <ul> 39 * <li>Hash (#) begins a comment line</li> 40 * 41 * <li>Non-comment lines have two or three components: 42 * LIBRARYNAME ENTRYPOINT [ CONFIGURATION .. ]</li> 43 * 44 * <li>Tabs or spaces separate the three items.</li> 45 * 46 * <li>LIBRARYNAME is the name of a shared library, either a short name if 47 * it is on the loader path, or a full pathname.</li> 48 * 49 * <li>ENTRYPOINT is the short (undecorated) symbol name of the plugin's 50 * entrypoint, as above.</li> 51 * 52 * <li>CONFIGURATION is the entire rest of the line . It's passed as-is to 53 * the plugin.</li> 54 * </ul> 55 * 56 * <p>An example configuration file is, in its entirety:</p> 57 * 58 * \code 59 * # this is icuplugins44.txt 60 * testplug.dll myPlugin hello=world 61 * \endcode 62 * <p>Plugins are categorized as "high" or "low" level. Low level are those 63 * which must be run BEFORE high level plugins, and before any operations 64 * which cause ICU to be 'initialized'. If a plugin is low level but 65 * causes ICU to allocate memory or become initialized, that plugin is said 66 * to cause a 'level change'. </p> 67 * 68 * <p>At load time, ICU first queries all plugins to determine their level, 69 * then loads all 'low' plugins first, and then loads all 'high' plugins. 70 * Plugins are otherwise loaded in the order listed in the configuration file.</p> 71 * 72 * <h3>Implementing a Plugin</h3> 73 * \code 74 * U_CAPI UPlugTokenReturn U_EXPORT2 75 * myPlugin (UPlugData *plug, UPlugReason reason, UErrorCode *status) { 76 * if(reason==UPLUG_REASON_QUERY) { 77 * uplug_setPlugName(plug, "Simple Plugin"); 78 * uplug_setPlugLevel(plug, UPLUG_LEVEL_HIGH); 79 * } else if(reason==UPLUG_REASON_LOAD) { 80 * ... Set up some ICU things here.... 81 * } else if(reason==UPLUG_REASON_UNLOAD) { 82 * ... unload, clean up ... 83 * } 84 * return UPLUG_TOKEN; 85 * } 86 * \endcode 87 * 88 * <p>The UPlugData* is an opaque pointer to the plugin-specific data, and is 89 * used in all other API calls.</p> 90 * 91 * <p>The API contract is:</p> 92 * <ol><li>The plugin MUST always return UPLUG_TOKEN as a return value- to 93 * indicate that it is a valid plugin.</li> 94 * 95 * <li>When the 'reason' parameter is set to UPLUG_REASON_QUERY, the 96 * plugin MUST call uplug_setPlugLevel() to indicate whether it is a high 97 * level or low level plugin.</li> 98 * 99 * <li>When the 'reason' parameter is UPLUG_REASON_QUERY, the plugin 100 * SHOULD call uplug_setPlugName to indicate a human readable plugin name.</li></ol> 101 * 102 * 103 * \internal ICU 4.4 Technology Preview 104 */ 105 106 107 #ifndef ICUPLUG_H 108 #define ICUPLUG_H 109 110 #include "unicode/utypes.h" 111 112 113 #if UCONFIG_ENABLE_PLUGINS 114 115 116 117 /* === Basic types === */ 118 119 #ifndef U_HIDE_INTERNAL_API 120 /** 121 * @{ 122 * Opaque structure passed to/from a plugin. 123 * use the APIs to access it. 124 * @internal ICU 4.4 Technology Preview 125 */ 126 127 struct UPlugData; 128 typedef struct UPlugData UPlugData; 129 130 /** @} */ 131 132 /** 133 * Random Token to identify a valid ICU plugin. Plugins must return this 134 * from the entrypoint. 135 * @internal ICU 4.4 Technology Preview 136 */ 137 #define UPLUG_TOKEN 0x54762486 138 139 /** 140 * Max width of names, symbols, and configuration strings 141 * @internal ICU 4.4 Technology Preview 142 */ 143 #define UPLUG_NAME_MAX 100 144 145 146 /** 147 * Return value from a plugin entrypoint. 148 * Must always be set to UPLUG_TOKEN 149 * @see UPLUG_TOKEN 150 * @internal ICU 4.4 Technology Preview 151 */ 152 typedef uint32_t UPlugTokenReturn; 153 154 /** 155 * Reason code for the entrypoint's call 156 * @internal ICU 4.4 Technology Preview 157 */ 158 typedef enum { 159 UPLUG_REASON_QUERY = 0, /**< The plugin is being queried for info. **/ 160 UPLUG_REASON_LOAD = 1, /**< The plugin is being loaded. **/ 161 UPLUG_REASON_UNLOAD = 2, /**< The plugin is being unloaded. **/ 162 /** 163 * Number of known reasons. 164 * @internal The numeric value may change over time, see ICU ticket #12420. 165 */ 166 UPLUG_REASON_COUNT 167 } UPlugReason; 168 169 170 /** 171 * Level of plugin loading 172 * INITIAL: UNKNOWN 173 * QUERY: INVALID -> { LOW | HIGH } 174 * ERR -> INVALID 175 * @internal ICU 4.4 Technology Preview 176 */ 177 typedef enum { 178 UPLUG_LEVEL_INVALID = 0, /**< The plugin is invalid, hasn't called uplug_setLevel, or can't load. **/ 179 UPLUG_LEVEL_UNKNOWN = 1, /**< The plugin is waiting to be installed. **/ 180 UPLUG_LEVEL_LOW = 2, /**< The plugin must be called before u_init completes **/ 181 UPLUG_LEVEL_HIGH = 3, /**< The plugin can run at any time. **/ 182 /** 183 * Number of known levels. 184 * @internal The numeric value may change over time, see ICU ticket #12420. 185 */ 186 UPLUG_LEVEL_COUNT 187 } UPlugLevel; 188 189 /** 190 * Entrypoint for an ICU plugin. 191 * @param plug the UPlugData handle. 192 * @param status the plugin's extended status code. 193 * @return A valid plugin must return UPLUG_TOKEN 194 * @internal ICU 4.4 Technology Preview 195 */ 196 typedef UPlugTokenReturn (U_EXPORT2 UPlugEntrypoint) ( 197 UPlugData *plug, 198 UPlugReason reason, 199 UErrorCode *status); 200 201 /* === Needed for Implementing === */ 202 203 /** 204 * Request that this plugin not be unloaded at cleanup time. 205 * This is appropriate for plugins which cannot be cleaned up. 206 * @see u_cleanup() 207 * @param plug plugin 208 * @param dontUnload set true if this plugin can't be unloaded 209 * @internal ICU 4.4 Technology Preview 210 */ 211 U_INTERNAL void U_EXPORT2 212 uplug_setPlugNoUnload(UPlugData *plug, UBool dontUnload); 213 214 /** 215 * Set the level of this plugin. 216 * @param plug plugin data handle 217 * @param level the level of this plugin 218 * @internal ICU 4.4 Technology Preview 219 */ 220 U_INTERNAL void U_EXPORT2 221 uplug_setPlugLevel(UPlugData *plug, UPlugLevel level); 222 223 /** 224 * Get the level of this plugin. 225 * @param plug plugin data handle 226 * @return the level of this plugin 227 * @internal ICU 4.4 Technology Preview 228 */ 229 U_INTERNAL UPlugLevel U_EXPORT2 230 uplug_getPlugLevel(UPlugData *plug); 231 232 /** 233 * Get the lowest level of plug which can currently load. 234 * For example, if UPLUG_LEVEL_LOW is returned, then low level plugins may load 235 * if UPLUG_LEVEL_HIGH is returned, then only high level plugins may load. 236 * @return the lowest level of plug which can currently load 237 * @internal ICU 4.4 Technology Preview 238 */ 239 U_INTERNAL UPlugLevel U_EXPORT2 240 uplug_getCurrentLevel(void); 241 242 243 /** 244 * Get plug load status 245 * @return The error code of this plugin's load attempt. 246 * @internal ICU 4.4 Technology Preview 247 */ 248 U_INTERNAL UErrorCode U_EXPORT2 249 uplug_getPlugLoadStatus(UPlugData *plug); 250 251 /** 252 * Set the human-readable name of this plugin. 253 * @param plug plugin data handle 254 * @param name the name of this plugin. The first UPLUG_NAME_MAX characters willi be copied into a new buffer. 255 * @internal ICU 4.4 Technology Preview 256 */ 257 U_INTERNAL void U_EXPORT2 258 uplug_setPlugName(UPlugData *plug, const char *name); 259 260 /** 261 * Get the human-readable name of this plugin. 262 * @param plug plugin data handle 263 * @return the name of this plugin 264 * @internal ICU 4.4 Technology Preview 265 */ 266 U_INTERNAL const char * U_EXPORT2 267 uplug_getPlugName(UPlugData *plug); 268 269 /** 270 * Return the symbol name for this plugin, if known. 271 * @param plug plugin data handle 272 * @return the symbol name, or NULL 273 * @internal ICU 4.4 Technology Preview 274 */ 275 U_INTERNAL const char * U_EXPORT2 276 uplug_getSymbolName(UPlugData *plug); 277 278 /** 279 * Return the library name for this plugin, if known. 280 * @param plug plugin data handle 281 * @param status error code 282 * @return the library name, or NULL 283 * @internal ICU 4.4 Technology Preview 284 */ 285 U_INTERNAL const char * U_EXPORT2 286 uplug_getLibraryName(UPlugData *plug, UErrorCode *status); 287 288 /** 289 * Return the library used for this plugin, if known. 290 * Plugins could use this to load data out of their 291 * @param plug plugin data handle 292 * @return the library, or NULL 293 * @internal ICU 4.4 Technology Preview 294 */ 295 U_INTERNAL void * U_EXPORT2 296 uplug_getLibrary(UPlugData *plug); 297 298 /** 299 * Return the plugin-specific context data. 300 * @param plug plugin data handle 301 * @return the context, or NULL if not set 302 * @internal ICU 4.4 Technology Preview 303 */ 304 U_INTERNAL void * U_EXPORT2 305 uplug_getContext(UPlugData *plug); 306 307 /** 308 * Set the plugin-specific context data. 309 * @param plug plugin data handle 310 * @param context new context to set 311 * @internal ICU 4.4 Technology Preview 312 */ 313 U_INTERNAL void U_EXPORT2 314 uplug_setContext(UPlugData *plug, void *context); 315 316 317 /** 318 * Get the configuration string, if available. 319 * The string is in the platform default codepage. 320 * @param plug plugin data handle 321 * @return configuration string, or else null. 322 * @internal ICU 4.4 Technology Preview 323 */ 324 U_INTERNAL const char * U_EXPORT2 325 uplug_getConfiguration(UPlugData *plug); 326 327 /** 328 * Return all currently installed plugins, from newest to oldest 329 * Usage Example: 330 * \code 331 * UPlugData *plug = NULL; 332 * while(plug=uplug_nextPlug(plug)) { 333 * ... do something with 'plug' ... 334 * } 335 * \endcode 336 * Not thread safe- do not call while plugs are added or removed. 337 * @param prior pass in 'NULL' to get the first (most recent) plug, 338 * otherwise pass the value returned on a prior call to uplug_nextPlug 339 * @return the next oldest plugin, or NULL if no more. 340 * @internal ICU 4.4 Technology Preview 341 */ 342 U_INTERNAL UPlugData* U_EXPORT2 343 uplug_nextPlug(UPlugData *prior); 344 345 /** 346 * Inject a plugin as if it were loaded from a library. 347 * This is useful for testing plugins. 348 * Note that it will have a 'NULL' library pointer associated 349 * with it, and therefore no llibrary will be closed at cleanup time. 350 * Low level plugins may not be able to load, as ordering can't be enforced. 351 * @param entrypoint entrypoint to install 352 * @param config user specified configuration string, if available, or NULL. 353 * @param status error result 354 * @return the new UPlugData associated with this plugin, or NULL if error. 355 * @internal ICU 4.4 Technology Preview 356 */ 357 U_INTERNAL UPlugData* U_EXPORT2 358 uplug_loadPlugFromEntrypoint(UPlugEntrypoint *entrypoint, const char *config, UErrorCode *status); 359 360 361 /** 362 * Inject a plugin from a library, as if the information came from a config file. 363 * Low level plugins may not be able to load, and ordering can't be enforced. 364 * @param libName DLL name to load 365 * @param sym symbol of plugin (UPlugEntrypoint function) 366 * @param config configuration string, or NULL 367 * @param status error result 368 * @return the new UPlugData associated with this plugin, or NULL if error. 369 * @internal ICU 4.4 Technology Preview 370 */ 371 U_INTERNAL UPlugData* U_EXPORT2 372 uplug_loadPlugFromLibrary(const char *libName, const char *sym, const char *config, UErrorCode *status); 373 374 /** 375 * Remove a plugin. 376 * Will request the plugin to be unloaded, and close the library if needed 377 * @param plug plugin handle to close 378 * @param status error result 379 * @internal ICU 4.4 Technology Preview 380 */ 381 U_INTERNAL void U_EXPORT2 382 uplug_removePlug(UPlugData *plug, UErrorCode *status); 383 #endif /* U_HIDE_INTERNAL_API */ 384 385 #endif /* UCONFIG_ENABLE_PLUGINS */ 386 387 #endif /* _ICUPLUG */ 388 389