initial check-in

1 files changed, 173 insertions, 0 deletions

diff --git a/eio.h b/eio.h
new file mode 100644
index 0000000..9de84d0
--- /dev/null
+++ b/eio.h
@@ -0,0 +1,173 @@
+#ifndef EIO_H_
+#define EIO_H_
+
+#include <stddef.h>
+#include <stdlib.h>
+
+typedef struct eio_req eio_req;
+
+typedef int (*eio_cb)(eio_req *req);
+
+#ifndef EIO_COMMON
+# define EIO_COMMON		\
+  eio_cb finish;		\
+  void (*destroy)(eio_req *req);\
+  void *data
+#endif
+
+enum {
+  EIO_QUIT,
+  EIO_OPEN, EIO_CLOSE, EIO_DUP2,
+  EIO_READ, EIO_WRITE,
+  EIO_READAHEAD, EIO_SENDFILE,
+  EIO_STAT, EIO_LSTAT, EIO_FSTAT,
+  EIO_TRUNCATE, EIO_FTRUNCATE,
+  EIO_UTIME, EIO_FUTIME,
+  EIO_CHMOD, EIO_FCHMOD,
+  EIO_CHOWN, EIO_FCHOWN,
+  EIO_SYNC, EIO_FSYNC, EIO_FDATASYNC,
+  EIO_UNLINK, EIO_RMDIR, EIO_MKDIR, EIO_RENAME,
+  EIO_MKNOD, EIO_READDIR,
+  EIO_LINK, EIO_SYMLINK, EIO_READLINK,
+  EIO_GROUP, EIO_NOP,
+  EIO_BUSY,
+};
+
+typedef double eio_tstamp; /* feel free to use double in your code directly */
+
+/* eio request structure */
+/* this structure is mostly read-only */
+struct eio_req
+{
+  eio_req volatile *next; /* private */
+
+  ssize_t result;  /* result of syscall, e.g. result = read (... */
+  off_t offs;      /* read, write, truncate, readahead: file offset; mknod: dev_t */
+  size_t size;     /* read, write, readahead, sendfile: length */
+  void *ptr1;      /* all applicable requests: pathname, old name */
+  void *ptr2;      /* all applicable requests: new name or memory buffer */
+  eio_tstamp nv1;      /* utime, futime: atime; busy: sleep time */
+  eio_tstamp nv2;      /* utime, futime: mtime */
+
+  int type;        /* EIO_xxx constant */
+  int int1;        /* all applicable requests: file descriptor; sendfile: output fd; open: flags */
+  long int2;       /* chown, fchown: uid; sendfile: input fd; open, chmod, mkdir, mknod: file mode */
+  long int3;       /* chown, fchown: gid */
+  int errorno;     /* errno value on syscall return */
+
+  unsigned char flags; /* private */
+  unsigned char pri; /* the priority */
+
+  void (*feed)(eio_req *req);
+
+  EIO_COMMON;
+
+  eio_req *grp, *grp_prev, *grp_next, *grp_first; /* private */
+};
+
+enum {
+  EIO_FLAG_CANCELLED = 0x01, /* request was cancelled */
+  EIO_FLAG_PTR2_FREE = 0x02, /* need to free(ptr2) */
+};
+
+enum {
+  EIO_PRI_MIN     = -4,
+  EIO_PRI_MAX     =  4,
+
+  EIO_DEFAULT_PRI = 0,
+  EIO_PRI_BIAS    = -EIO_PRI_MIN,
+  EIO_NUM_PRI     = EIO_PRI_MAX + EIO_PRI_BIAS + 1,
+};
+
+/* returns < 0 on error, errno set
+ * need_poll, if non-zero, will be called when results are available
+ * and eio_poll_cb needs to be invoked (it MUST NOT call eio_poll_cb itself).
+ * done_poll is called when the need to poll is gone.
+ */
+int eio_init (void (*want_poll)(void), void (*done_poll)(void));
+
+/* must be called regularly to handle pending requests */
+/* returns 0 if all requests were handled, -1 if not, or the value of EIO_FINISH if != 0 */
+int eio_poll (void);
+
+/* stop polling if poll took longer than duration seconds */
+void eio_set_max_poll_time (eio_tstamp nseconds);
+/* do not handle more then count requests in one call to eio_poll_cb */
+void eio_set_max_poll_reqs (unsigned int nreqs);
+/* when != 0, then eio_submit blocks as long as nready > count */
+void eio_set_max_outstanding (unsigned int maxreqs);
+/* set maxinum number of idle threads */
+void eio_set_max_idle (unsigned int nthreads);
+
+/* set minimum required number
+ * maximum wanted number
+ * or maximum idle number of threads */
+void eio_set_min_parallel (unsigned int nthreads);
+void eio_set_max_parallel (unsigned int nthreads);
+void eio_set_max_idle     (unsigned int nthreads);
+
+unsigned int eio_nreqs    (void); /* number of requests in-flight */
+unsigned int eio_nready   (void); /* number of not-yet handled requests */
+unsigned int eio_npending (void); /* numbe rof finished but unhandled requests */
+unsigned int eio_nthreads (void); /* number of worker threads in use currently */
+
+/*****************************************************************************/
+/* high-level request API */
+
+eio_req *eio_fsync     (int fd, eio_cb cb);
+eio_req *eio_fdatasync (int fd, eio_cb cb);
+eio_req *eio_dupclose  (int fd, eio_cb cb);
+eio_req *eio_readahead (int fd, off_t offset, size_t length, eio_cb cb);
+eio_req *eio_read      (int fd, off_t offs, size_t length, char *data, eio_cb cb);
+eio_req *eio_write     (int fd, off_t offs, size_t length, char *data, eio_cb cb);
+eio_req *eio_fstat     (int fd, eio_cb cb); /* stat buffer=ptr2 allocates dynamically */
+eio_req *eio_futime    (int fd, eio_tstamp atime, eio_tstamp mtime, eio_cb cb);
+eio_req *eio_ftruncate (int fd, off_t offset, eio_cb cb);
+eio_req *eio_fchmod    (int fd, mode_t mode, eio_cb cb);
+eio_req *eio_fchown    (int fd, uid_t uid, gid_t gid, eio_cb cb);
+eio_req *eio_dup2      (int fd, int fd2, eio_cb cb);
+eio_req *eio_sendfile  (int out_fd, int in_fd, off_t in_offset, size_t length, eio_cb cb);
+eio_req *eio_open      (const char *path, int flags, mode_t mode, eio_cb cb);
+eio_req *eio_readlink  (const char *path, eio_cb cb); /* result=ptr2 allocated dynamically */
+eio_req *eio_stat      (const char *path, eio_cb cb); /* stat buffer=ptr2 allocates dynamically */
+eio_req *eio_lstat     (const char *path, eio_cb cb); /* stat buffer=ptr2 allocates dynamically */
+eio_req *eio_utime     (const char *path, eio_tstamp atime, eio_tstamp mtime, eio_cb cb);
+eio_req *eio_truncate  (const char *path, off_t offset, eio_cb cb);
+eio_req *eio_chmod     (const char *path, mode_t mode, eio_cb cb);
+eio_req *eio_mkdir     (const char *path, mode_t mode, eio_cb cb);
+eio_req *eio_chown     (const char *path, uid_t uid, gid_t gid, eio_cb cb);
+eio_req *eio_unlink    (const char *path, eio_cb cb);
+eio_req *eio_rmdir     (const char *path, eio_cb cb);
+eio_req *eio_readdir   (const char *path, eio_cb cb); /* result=ptr2 allocated dynamically */
+eio_req *eio_mknod     (const char *path, mode_t mode, dev_t dev, eio_cb cb);
+eio_req *eio_busy      (eio_tstamp delay, eio_cb cb); /* ties a thread for this long, simulating busyness */
+eio_req *eio_nop       (eio_cb cb); /* does nothing except go through the whole process */
+
+/* for groups */
+eio_req *eio_grp       (eio_cb cb);
+void eio_grp_feed      (eio_req *grp, int limit, void (*feed)(eio_req *req));
+void eio_grp_add       (eio_req *grp, eio_req *req);
+void eio_grp_cancel    (eio_req *grp); /* cancels all sub requests but not the group */
+
+/*****************************************************************************/
+/* low-level request API */
+
+/* must be used to initialise eio_req's */
+#define EIO_INIT(req,prio,finish_cb, destroy_cb)	\
+  memset ((req), 0, sizeof (eio_req));	\
+  (req)->pri = (prio) + EIO_PRI_BIAS;	\
+  (req)->finish  = (finish_cb);		\
+  (req)->destroy = (destroy_cb)
+
+/* true if the request was cancelled, useful in the invoke callback */
+#define EIO_CANCELLED(req) ((req)->flags & EIO_FLAG_CANCELLED)
+
+/* submit a request for execution */
+void eio_submit (eio_req *req);
+/* cancel a request as soon fast as possible */
+void eio_cancel (eio_req *req);
+/* destroy a request that has never been submitted */
+void eio_destroy (eio_req *req);
+
+#endif
+