diff options
Diffstat (limited to 'ext/kgio/write.c')
| -rw-r--r-- | ext/kgio/write.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/ext/kgio/write.c b/ext/kgio/write.c new file mode 100644 index 0000000..53b5b54 --- /dev/null +++ b/ext/kgio/write.c @@ -0,0 +1,212 @@ +/* we do not modify RSTRING pointers here */ +#include "kgio.h" +#include "my_fileno.h" +#include "nonblock.h" +static VALUE sym_wait_writable; + +/* prefer rb_str_subseq because we don't use negative offsets */ +#ifndef HAVE_RB_STR_SUBSEQ +#define rb_str_subseq rb_str_substr +#endif + +struct wr_args { + VALUE io; + VALUE buf; + const char *ptr; + long len; + int fd; +}; + +static void prepare_write(struct wr_args *a, VALUE io, VALUE str) +{ + a->buf = (TYPE(str) == T_STRING) ? str : rb_obj_as_string(str); + a->ptr = RSTRING_PTR(a->buf); + a->len = RSTRING_LEN(a->buf); + a->io = io; + a->fd = my_fileno(io); +} + +static int write_check(struct wr_args *a, long n, const char *msg, int io_wait) +{ + if (a->len == n) { +done: + a->buf = Qnil; + } else if (n < 0) { + if (errno == EINTR) { + a->fd = my_fileno(a->io); + return -1; + } + if (errno == EAGAIN) { + long written = RSTRING_LEN(a->buf) - a->len; + + if (io_wait) { + (void)kgio_call_wait_writable(a->io); + + /* buf may be modified in other thread/fiber */ + a->len = RSTRING_LEN(a->buf) - written; + if (a->len <= 0) + goto done; + a->ptr = RSTRING_PTR(a->buf) + written; + return -1; + } else if (written > 0) { + a->buf = rb_str_subseq(a->buf, written, a->len); + } else { + a->buf = sym_wait_writable; + } + return 0; + } + kgio_wr_sys_fail(msg); + } else { + assert(n >= 0 && n < a->len && "write/send syscall broken?"); + a->ptr += n; + a->len -= n; + return -1; + } + return 0; +} + +static VALUE my_write(VALUE io, VALUE str, int io_wait) +{ + struct wr_args a; + long n; + + prepare_write(&a, io, str); + set_nonblocking(a.fd); +retry: + n = (long)write(a.fd, a.ptr, a.len); + if (write_check(&a, n, "write", io_wait) != 0) + goto retry; + if (TYPE(a.buf) != T_SYMBOL) + kgio_autopush_write(io); + return a.buf; +} + +/* + * call-seq: + * + * io.kgio_write(str) -> nil + * + * Returns nil when the write completes. + * + * This may block and call any method defined to +kgio_wait_writable+ + * for the class. + */ +static VALUE kgio_write(VALUE io, VALUE str) +{ + return my_write(io, str, 1); +} + +/* + * call-seq: + * + * io.kgio_trywrite(str) -> nil, String or :wait_writable + * + * Returns nil if the write was completed in full. + * + * Returns a String containing the unwritten portion if EAGAIN + * was encountered, but some portion was successfully written. + * + * Returns :wait_writable if EAGAIN is encountered and nothing + * was written. + */ +static VALUE kgio_trywrite(VALUE io, VALUE str) +{ + return my_write(io, str, 0); +} + +#ifdef USE_MSG_DONTWAIT +/* + * This method behaves like Kgio::PipeMethods#kgio_write, except + * it will use send(2) with the MSG_DONTWAIT flag on sockets to + * avoid unnecessary calls to fcntl(2). + */ +static VALUE my_send(VALUE io, VALUE str, int io_wait) +{ + struct wr_args a; + long n; + + prepare_write(&a, io, str); +retry: + n = (long)send(a.fd, a.ptr, a.len, MSG_DONTWAIT); + if (write_check(&a, n, "send", io_wait) != 0) + goto retry; + if (TYPE(a.buf) != T_SYMBOL) + kgio_autopush_send(io); + return a.buf; +} + +/* + * This method may be optimized on some systems (e.g. GNU/Linux) to use + * MSG_DONTWAIT to avoid explicitly setting the O_NONBLOCK flag via fcntl. + * Otherwise this is the same as Kgio::PipeMethods#kgio_write + */ +static VALUE kgio_send(VALUE io, VALUE str) +{ + return my_send(io, str, 1); +} + +/* + * This method may be optimized on some systems (e.g. GNU/Linux) to use + * MSG_DONTWAIT to avoid explicitly setting the O_NONBLOCK flag via fcntl. + * Otherwise this is the same as Kgio::PipeMethods#kgio_trywrite + */ +static VALUE kgio_trysend(VALUE io, VALUE str) +{ + return my_send(io, str, 0); +} +#else /* ! USE_MSG_DONTWAIT */ +# define kgio_send kgio_write +# define kgio_trysend kgio_trywrite +#endif /* ! USE_MSG_DONTWAIT */ + +/* + * call-seq: + * + * Kgio.trywrite(io, str) -> nil, String or :wait_writable + * + * Returns nil if the write was completed in full. + * + * Returns a String containing the unwritten portion if EAGAIN + * was encountered, but some portion was successfully written. + * + * Returns :wait_writable if EAGAIN is encountered and nothing + * was written. + * + * Maybe used in place of PipeMethods#kgio_trywrite for non-Kgio objects + */ +static VALUE s_trywrite(VALUE mod, VALUE io, VALUE str) +{ + return my_write(io, str, 0); +} + +void init_kgio_write(void) +{ + VALUE mPipeMethods, mSocketMethods; + VALUE mKgio = rb_define_module("Kgio"); + + sym_wait_writable = ID2SYM(rb_intern("wait_writable")); + + rb_define_singleton_method(mKgio, "trywrite", s_trywrite, 2); + + /* + * Document-module: Kgio::PipeMethods + * + * This module may be used used to create classes that respond to + * various Kgio methods for reading and writing. This is included + * in Kgio::Pipe by default. + */ + mPipeMethods = rb_define_module_under(mKgio, "PipeMethods"); + rb_define_method(mPipeMethods, "kgio_write", kgio_write, 1); + rb_define_method(mPipeMethods, "kgio_trywrite", kgio_trywrite, 1); + + /* + * Document-module: Kgio::SocketMethods + * + * This method behaves like Kgio::PipeMethods, but contains + * optimizations for sockets on certain operating systems + * (e.g. GNU/Linux). + */ + mSocketMethods = rb_define_module_under(mKgio, "SocketMethods"); + rb_define_method(mSocketMethods, "kgio_write", kgio_send, 1); + rb_define_method(mSocketMethods, "kgio_trywrite", kgio_trysend, 1); +} |