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0001 /*
0002  * Copyright 2011 Red Hat, Inc.
0003  *
0004  * Permission is hereby granted, free of charge, to any person
0005  * obtaining a copy of this software and associated documentation files
0006  * (the "Software"), to deal in the Software without restriction,
0007  * including without limitation the rights to use, copy, modify, merge,
0008  * publish, distribute, sublicense, and/or sell copies of the Software,
0009  * and to permit persons to whom the Software is furnished to do so,
0010  * subject to the following conditions:
0011  *
0012  * The above copyright notice and this permission notice shall be
0013  * included in all copies or substantial portions of the Software.
0014  *
0015  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
0016  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
0017  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
0018  * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
0019  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
0020  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
0021  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
0022  * SOFTWARE.
0023  */
0024 
0025 #ifndef VERTO_H_
0026 #define VERTO_H_
0027 
0028 #include <time.h>   /* For time_t */
0029 #include <unistd.h> /* For pid_t */
0030 
0031 #ifdef WIN32
0032 #include <windows.h>
0033 typedef HANDLE verto_proc;
0034 typedef DWORD verto_proc_status;
0035 #else
0036 #include <sys/types.h>
0037 typedef pid_t verto_proc;
0038 typedef int verto_proc_status;
0039 #endif
0040 
0041 #define VERTO_SIG_IGN ((verto_callback *) 1)
0042 
0043 #ifdef __cplusplus
0044 extern "C"
0045 {
0046 #endif /* __cplusplus */
0047 
0048 typedef struct verto_ctx verto_ctx;
0049 typedef struct verto_ev verto_ev;
0050 
0051 typedef enum {
0052     VERTO_EV_TYPE_NONE = 0,
0053     VERTO_EV_TYPE_IO = 1,
0054     VERTO_EV_TYPE_TIMEOUT = 1 << 1,
0055     VERTO_EV_TYPE_IDLE = 1 << 2,
0056     VERTO_EV_TYPE_SIGNAL = 1 << 3,
0057     VERTO_EV_TYPE_CHILD = 1 << 4
0058 } verto_ev_type;
0059 
0060 typedef enum {
0061     VERTO_EV_FLAG_NONE = 0,
0062     VERTO_EV_FLAG_PERSIST = 1,
0063     VERTO_EV_FLAG_PRIORITY_LOW = 1 << 1,
0064     VERTO_EV_FLAG_PRIORITY_MEDIUM = 1 << 2,
0065     VERTO_EV_FLAG_PRIORITY_HIGH = 1 << 3,
0066     VERTO_EV_FLAG_IO_READ = 1 << 4,
0067     VERTO_EV_FLAG_IO_WRITE = 1 << 5,
0068     VERTO_EV_FLAG_IO_ERROR = 1 << 7,
0069     VERTO_EV_FLAG_IO_CLOSE_FD = 1 << 8,
0070     VERTO_EV_FLAG_REINITIABLE = 1 << 6,
0071     _VERTO_EV_FLAG_MUTABLE_MASK = VERTO_EV_FLAG_PRIORITY_LOW
0072                                   | VERTO_EV_FLAG_PRIORITY_MEDIUM
0073                                   | VERTO_EV_FLAG_PRIORITY_HIGH
0074                                   | VERTO_EV_FLAG_IO_READ
0075                                   | VERTO_EV_FLAG_IO_WRITE,
0076     _VERTO_EV_FLAG_MAX = VERTO_EV_FLAG_IO_CLOSE_FD
0077 } verto_ev_flag;
0078 
0079 typedef void (verto_callback)(verto_ctx *ctx, verto_ev *ev);
0080 
0081 /**
0082  * Creates a new event context using an optionally specified implementation
0083  * and/or optionally specified required features.
0084  *
0085  * If you are an application that has already decided on using a particular
0086  * event loop implementation, you should not call this function, but instead
0087  * import the verto-NAME.h header and link against the verto-NAME.so, where
0088  * NAME is the implementation you wish to use.
0089  *
0090  * If you are a library, you should generally avoid creating event contexts
0091  * on your own but allow applications to pass in a verto_ctx you can use.
0092  *
0093  * There are two cases where you should use this function.  The first is
0094  * where you have a need to choose an implementation at run time, usually
0095  * for testing purposes.  The second and more common is when you simply
0096  * wish to remain implementation agnostic.  In this later case, you should
0097  * always call like this: verto_new(NULL, ...).  This lets verto choose the best
0098  * implementation to use.
0099  *
0100  * If impl is not NULL, a new context is returned which is backed by the
0101  * implementation specified. If the implementation specified is not
0102  * available or if the required types (reqtypes) are not provided by the
0103  * named implementation, NULL is returned. The parameter 'impl' can specify:
0104  *   * The full path to an implementation library
0105  *   * The name of the implementation library (i.e. - "glib" or "libev")
0106  *
0107  * If impl is NULL, verto will attempt to automatically determine the
0108  * best implementation to use.
0109  *
0110  * First, verto will attempt to use an existing, previously loaded
0111  * implementation. This is handled automatically by internal caching of either
0112  * the first implementation loaded or the one specified by verto_set_default().
0113  *
0114  * Second, verto will attempt to discern if you are already linked to any
0115  * of the supported implementations (to avoid wasting memory by loading
0116  * extra unnecessary libraries).  If you are linked to one supported
0117  * implementation, that implementation will be chosen.  If you are linked
0118  * to more than one supported implementation one of the ones linked to
0119  * will be chosen, but the order of the particular choice is undefined.
0120  *
0121  * Third, verto will attempt to load the compile-time default, if defined at
0122  * build time and available at runtime.
0123  *
0124  * Last, verto will attempt to load any implementation installed. The specific
0125  * order of this step is undefined.
0126  *
0127  * In all cases above, if the implementation does not support all the specified
0128  * features (reqtypes), it will be skipped and processing will continue from
0129  * where it left off. This means that if verto_new() returns non-NULL it is
0130  * guaranteed to support the features you specified.
0131  *
0132  * @see verto_set_default()
0133  * @param impl The implementation to use, or NULL.
0134  * @param reqtypes A bitwise or'd list of required event type features.
0135  * @return A new verto_ctx, or NULL on error.  Call verto_free() when done.
0136  */
0137 verto_ctx *
0138 verto_new(const char *impl, verto_ev_type reqtypes);
0139 
0140 /**
0141  * Gets the default event context using an optionally specified implementation.
0142  *
0143  * This function is essentially a singleton version of verto_new().  However,
0144  * since this function must return the same loop as the *_default() call of
0145  * the underlying implementation (if such a function exists), it is NOT a
0146  * global singleton, but a per-implementation singleton. For this reason, you
0147  * must call verto_free() when you are done with this loop. Even after calling
0148  * verto_free() on the default verto_ctx, you can safely call verto_default()
0149  * again and receive a new reference to the same (internally default) loop.
0150  *
0151  * In all other respects, verto_default() acts exactly like verto_new().
0152  *
0153  * @see verto_new()
0154  * @see verto_free()
0155  * @param impl The implementation to use, or NULL.
0156  * @param reqtypes A bitwise or'd list of required event type features.
0157  * @return The default verto_ctx, or NULL on error.  Call verto_free() when done.
0158  */
0159 verto_ctx *
0160 verto_default(const char *impl, verto_ev_type reqtypes);
0161 
0162 /**
0163  * Sets the default implementation to use by its name.
0164  *
0165  * This function returns 1 on success and 0 on failure.  It can fail for the
0166  * following reasons:
0167  *   1. The default implementation was already set via verto_set_default().
0168  *   2. The implementation specified could not be found.
0169  *   3. The implementation specified didn't support the features specified.
0170  *   4. The impl argument was NULL.
0171  *   5. verto_new() was already called.
0172  *   6. verto_default() was already called.
0173  *   7. verto_new_NAME() was already called.
0174  *   8. verto_default_NAME() was already called.
0175  *   9. verto_convert_NAME() was already called.
0176  *
0177  * @see verto_new()
0178  * @see verto_default()
0179  * @param impl The implementation to use.
0180  * @param reqtypes A bitwise or'd list of required event type features.
0181  * @return The default verto_ctx, or NULL on error.  Call verto_free() when done.
0182  */
0183 int
0184 verto_set_default(const char *impl, verto_ev_type reqtypes);
0185 
0186 /**
0187  * Sets the allocator to use for verto_ctx and verto_ev objects.
0188  *
0189  * If you plan to set the allocator, you MUST call this function before any
0190  * other verto_*() calls.
0191  *
0192  * @see verto_new()
0193  * @see verto_default()
0194  * @see verto_add_io()
0195  * @see verto_add_timeout()
0196  * @see verto_add_idle()
0197  * @see verto_add_signal()
0198  * @see verto_add_child()
0199  * @param resize The allocator to use (behaves like realloc();
0200  *        resize(ptr, 0) must free memory at ptr.)
0201  * @param hierarchical Zero if the allocator is not hierarchical
0202  */
0203 int
0204 verto_set_allocator(void *(*resize)(void *mem, size_t size), int hierarchical);
0205 
0206 /**
0207  * Frees a verto_ctx.
0208  *
0209  * When called on a default verto_ctx, the reference will be freed but the
0210  * internal default loop will still be available via another call to
0211  * verto_default().
0212  *
0213  * @see verto_new()
0214  * @see verto_default()
0215  * @param ctx The verto_ctx to free.
0216  */
0217 void
0218 verto_free(verto_ctx *ctx);
0219 
0220 /**
0221  * Frees global state.
0222  *
0223  * Remove and free all allocated global state.  Call only when no further
0224  * contexts exist and all threads have exited.
0225  *
0226  * @see verto_new()
0227  * @see verto_free()
0228  * @see verto_default()
0229  */
0230 void
0231 verto_cleanup(void);
0232 
0233 /**
0234  * Run the verto_ctx forever, or at least until verto_break() is called.
0235  *
0236  * @see verto_break()
0237  * @param ctx The verto_ctx to run.
0238  */
0239 void
0240 verto_run(verto_ctx *ctx);
0241 
0242 /**
0243  * Run the verto_ctx once. May block.
0244  *
0245  * @param ctx The verto_ctx to run once.
0246  */
0247 void
0248 verto_run_once(verto_ctx *ctx);
0249 
0250 /**
0251  * Exits the currently running verto_ctx.
0252  *
0253  * @see verto_run()
0254  * @param ctx The verto_ctx to exit.
0255  */
0256 void
0257 verto_break(verto_ctx *ctx);
0258 
0259 /**
0260  * Re-initializes the verto_ctx.
0261  *
0262  * This function deletes all events, except those which have set the
0263  * VERTO_EV_FLAG_REINITIABLE flag. If you fork(), you MUST call this in the
0264  * child process after the fork!
0265  *
0266  * If this function fails it indicates that at least one
0267  * VERTO_EV_FLAG_REINITIABLE event was not rearmed or that ctx was NULL.
0268  *
0269  * @see verto_new()
0270  * @see verto_default()
0271  * @param ctx The verto_ctx to re-initialize.
0272  * @return Non-zero on success, 0 on error.
0273  */
0274 int
0275 verto_reinitialize(verto_ctx *ctx);
0276 
0277 /**
0278  * Adds a callback executed when a file descriptor is ready to be read/written.
0279  *
0280  * All verto_ev events are automatically freed when their parent verto_ctx is
0281  * freed. You do not need to free them manually. If VERTO_EV_FLAG_PERSIST is
0282  * provided, the event will repeat until verto_del() is called. If
0283  * VERTO_EV_FLAG_PERSIST is not provided, the event will be freed automatically
0284  * after its execution. In either case, you may call verto_del() at any time
0285  * to prevent the event from executing.
0286  * If VERTO_EV_FLAG_IO_CLOSE_FD is provided the passed in fd is automatically
0287  * closed when the event is freed with verto_del()
0288  *
0289  * NOTE: On Windows, the underlying select() only works with sockets. As such,
0290  * any attempt to add a non-socket io event on Windows will produce undefined
0291  * results and may even crash.
0292  *
0293  * @see verto_del()
0294  * @param ctx The verto_ctx which will fire the callback.
0295  * @param flags The flags to set (at least one VERTO_EV_FLAG_IO* required).
0296  * @param callback The callback to fire.
0297  * @param fd The file descriptor to watch for reads.
0298  * @return The verto_ev registered with the event context or NULL on error.
0299  */
0300 verto_ev *
0301 verto_add_io(verto_ctx *ctx, verto_ev_flag flags,
0302              verto_callback *callback, int fd);
0303 
0304 /**
0305  * Adds a callback executed after a period of time.
0306  *
0307  * All verto_ev events are automatically freed when their parent verto_ctx is
0308  * freed. You do not need to free them manually. If VERTO_EV_FLAG_PERSIST is
0309  * provided, the event will repeat until verto_del() is called. If
0310  * VERTO_EV_FLAG_PERSIST is not provided, the event will be freed automatically
0311  * after its execution. In either case, you may call verto_del() at any time
0312  * to prevent the event from executing.
0313  *
0314  * @see verto_del()
0315  * @param ctx The verto_ctx which will fire the callback.
0316  * @param flags The flags to set.
0317  * @param callback The callback to fire.
0318  * @param interval Time period to wait before firing (in milliseconds).
0319  * @return The verto_ev registered with the event context.
0320  */
0321 verto_ev *
0322 verto_add_timeout(verto_ctx *ctx, verto_ev_flag flags,
0323                   verto_callback *callback, time_t interval);
0324 
0325 /**
0326  * Adds a callback executed when there is nothing else to do.
0327  *
0328  * All verto_ev events are automatically freed when their parent verto_ctx is
0329  * freed. You do not need to free them manually. If VERTO_EV_FLAG_PERSIST is
0330  * provided, the event will repeat until verto_del() is called. If
0331  * VERTO_EV_FLAG_PERSIST is not provided, the event will be freed automatically
0332  * after its execution. In either case, you may call verto_del() at any time
0333  * to prevent the event from executing.
0334  *
0335  * @see verto_del()
0336  * @param ctx The verto_ctx which will fire the callback.
0337  * @param flags The flags to set.
0338  * @param callback The callback to fire.
0339  * @return The verto_ev registered with the event context.
0340  */
0341 verto_ev *
0342 verto_add_idle(verto_ctx *ctx, verto_ev_flag flags,
0343                verto_callback *callback);
0344 
0345 /**
0346  * Adds a callback executed when a signal is received.
0347  *
0348  * All verto_ev events are automatically freed when their parent verto_ctx is
0349  * freed. You do not need to free them manually. If VERTO_EV_FLAG_PERSIST is
0350  * provided, the event will repeat until verto_del() is called. If
0351  * VERTO_EV_FLAG_PERSIST is not provided, the event will be freed automatically
0352  * after its execution. In either case, you may call verto_del() at any time
0353  * to prevent the event from executing.
0354  *
0355  * NOTE: If you attempt to ignore a signal without the VERTO_EV_FLAG_PERSIST
0356  * flag, this function fails.
0357  *
0358  * NOTE: SIGCHLD is expressly not supported. If you want this notification,
0359  * please use verto_add_child().
0360  *
0361  * WARNNIG: Signal events can only be reliably received in the default verto_ctx
0362  * in some implementations.  Attempting to receive signal events in non-default
0363  * loops may result in assert() failures.
0364  *
0365  * WARNING: While verto does its best to protect you from crashes, there is
0366  * essentially no way to do signal events if you mix multiple implementations in
0367  * a single process. Attempting to do so will result in undefined behavior,
0368  * and potentially even a crash. You have been warned.
0369  *
0370  * @see verto_add_child()
0371  * @see verto_repeat()
0372  * @see verto_del()
0373  * @param ctx The verto_ctx which will fire the callback.
0374  * @param flags The flags to set.
0375  * @param callback The callback to fire.
0376  * @param signal The signal to watch for.
0377  * @return The verto_ev registered with the event context.
0378  */
0379 verto_ev *
0380 verto_add_signal(verto_ctx *ctx, verto_ev_flag flags,
0381                  verto_callback *callback, int signal);
0382 
0383 /**
0384  * Adds a callback executed when a child process exits.
0385  *
0386  * This event will be freed automatically after its execution. Due to the
0387  * nature of a process' life-cycle, child events cannot persist (processes only
0388  * exit once). This function returns NULL if you attempt to use
0389  * VERTO_EV_FLAG_PERSIST. You may, of course, call verto_del() at any time to
0390  * prevent the callback from firing.
0391  *
0392  * @see verto_del()
0393  * @param ctx The verto_ctx which will fire the callback.
0394  * @param flags The flags to set.
0395  * @param callback The callback to fire.
0396  * @param child The pid (POSIX) or handle (Win32) of the child to watch for.
0397  * @return The verto_ev registered with the event context.
0398  */
0399 verto_ev *
0400 verto_add_child(verto_ctx *ctx, verto_ev_flag flags,
0401                 verto_callback *callback, verto_proc proc);
0402 
0403 /**
0404  * Sets the private pointer of the verto_ev.
0405  *
0406  * The free callback will be called in two cases:
0407  *   1. When the event is deleted (manually or automatically)
0408  *   2. When verto_set_private() is called again, unless
0409  *      free is NULL.
0410  *
0411  * @see verto_get_private()
0412  * @param ev The verto_ev
0413  * @param priv The private value to store
0414  * @param free The callback used to free the data or NULL
0415  */
0416 void
0417 verto_set_private(verto_ev *ev, void *priv, verto_callback *free);
0418 
0419 /**
0420  * Gets the private pointer of the verto_ev.
0421  *
0422  * @see verto_set_private()
0423  * @param ev The verto_ev
0424  * @return The verto_ev private pointer
0425  */
0426 void *
0427 verto_get_private(const verto_ev *ev);
0428 
0429 /**
0430  * Gets the type of the verto_ev.
0431  *
0432  * @see verto_add_io()
0433  * @see verto_add_timeout()
0434  * @see verto_add_idle()
0435  * @see verto_add_signal()
0436  * @see verto_add_child()
0437  * @param ev The verto_ev
0438  * @return The verto_ev type
0439  */
0440 verto_ev_type
0441 verto_get_type(const verto_ev *ev);
0442 
0443 /**
0444  * Gets the flags associated with the given verto_ev.
0445  *
0446  * @see verto_add_io()
0447  * @see verto_add_timeout()
0448  * @see verto_add_idle()
0449  * @see verto_add_signal()
0450  * @see verto_add_child()
0451  * @see verto_set_flags()
0452  * @param ev The verto_ev
0453  * @return The verto_ev type
0454  */
0455 verto_ev_flag
0456 verto_get_flags(const verto_ev *ev);
0457 
0458 /**
0459  * Sets the flags associated with the given verto_ev.
0460  *
0461  * See _VERTO_EV_FLAG_MUTABLE_MASK for the flags that can be changed
0462  * with this function. All others will be ignored. If the flags specified
0463  * are the same as the flags the event already has, this function is a no-op.
0464  *
0465  * @see verto_add_io()
0466  * @see verto_add_timeout()
0467  * @see verto_add_idle()
0468  * @see verto_add_signal()
0469  * @see verto_add_child()
0470  * @see verto_get_flags()
0471  * @param ev The verto_ev
0472  * @param flags The flags for the event
0473  */
0474 void
0475 verto_set_flags(verto_ev *ev, verto_ev_flag flags);
0476 
0477 /**
0478  * Gets the file descriptor associated with a read/write verto_ev.
0479  *
0480  * @see verto_add_io()
0481  * @param ev The verto_ev to retrieve the file descriptor from.
0482  * @return The file descriptor, or -1 if not a read/write event.
0483  */
0484 int
0485 verto_get_fd(const verto_ev *ev);
0486 
0487 /**
0488  * Gets the file descriptor state from when the event fires.
0489  *
0490  * @see verto_add_io()
0491  * @param ev The verto_ev to retrieve the fd state from.
0492  * @return The fd state.
0493  */
0494 verto_ev_flag
0495 verto_get_fd_state(const verto_ev *ev);
0496 
0497 /**
0498  * Gets the interval associated with a timeout verto_ev.
0499  *
0500  * @see verto_add_timeout()
0501  * @param ev The verto_ev to retrieve the interval from.
0502  * @return The interval, or 0 if not a timeout event.
0503  */
0504 time_t
0505 verto_get_interval(const verto_ev *ev);
0506 
0507 /**
0508  * Gets the signal associated with a signal verto_ev.
0509  *
0510  * @see verto_add_signal()
0511  * @param ev The verto_ev to retrieve the signal from.
0512  * @return The signal, or -1 if not a signal event.
0513  */
0514 int
0515 verto_get_signal(const verto_ev *ev);
0516 
0517 /**
0518  * Gets the process associated with a child verto_ev.
0519  *
0520  * @see verto_add_child()
0521  * @param ev The verto_ev to retrieve the process from.
0522  * @return The pid/handle, or 0/NULL if not a child event (POSIX/Win32).
0523  */
0524 verto_proc
0525 verto_get_proc(const verto_ev *ev);
0526 
0527 /**
0528  * Gets the status of the process which caused this event to fire.
0529  *
0530  * @see verto_add_child()
0531  * @param ev The verto_ev to retrieve the status from.
0532  * @return The pid/handle status.
0533  */
0534 verto_proc_status
0535 verto_get_proc_status(const verto_ev *ev);
0536 
0537 /**
0538  * Gets the verto_ctx associated with a verto_ev.
0539  *
0540  * This is a borrowed reference, don't attempt to free it!
0541  *
0542  * @param ev The verto_ev to retrieve the verto_ctx from.
0543  * @return The verto_ctx.
0544  */
0545 verto_ctx *
0546 verto_get_ctx(const verto_ev *ev);
0547 
0548 /**
0549  * Removes an event from from the event context and frees it.
0550  *
0551  * The event and its contents cannot be used after this call.
0552  *
0553  * @see verto_add_io()
0554  * @see verto_add_timeout()
0555  * @see verto_add_idle()
0556  * @see verto_add_signal()
0557  * @see verto_add_child()
0558  * @param ev The event to delete.
0559  */
0560 void
0561 verto_del(verto_ev *ev);
0562 
0563 /**
0564  * Returns the event types supported by this implementation.
0565  *
0566  * @param ctx The verto_ctx to query.
0567  * @return The event types supported.
0568  */
0569 verto_ev_type
0570 verto_get_supported_types(verto_ctx *ctx);
0571 
0572 #ifdef __cplusplus
0573 } /* extern "C" */
0574 #endif /* __cplusplus */
0575 #endif /* VERTO_H_ */