class Kgio::File
This subclass of the core File class adds the “tryopen” singleton method for opening files. A single “tryopen” and check for the return value may be used to avoid unnecessary stat(2) syscalls or File.open exceptions when checking for the existence of a file and opening it.
Public Class Methods
Kgio::File.tryopen(filename, [, mode [, perm]]) → Kgio::File or Symbol
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Returns a Kgio::File object on a successful open.
filename
is a path to any file on the filesystem. If
specified, mode
is a bitmask of flags (see IO.sysopen) and
perm
should be an octal number.
This does not raise errors for most failures, but installs returns a Ruby symbol for the constant in the Errno::* namespace.
Common error symbols are:
-
:ENOENT
-
:EACCES
See your open(2) manpage for more information on open(2) errors.
static VALUE s_tryopen(int argc, VALUE *argv, VALUE klass) { int fd; VALUE pathname, flags, mode; struct open_args o; int retried = 0; VALUE rv; rb_scan_args(argc, argv, "12", &pathname, &flags, &mode); if (rb_respond_to(pathname, id_to_path)) pathname = rb_funcall(pathname, id_to_path, 0); o.pathname = StringValueCStr(pathname); switch (TYPE(flags)) { case T_NIL: o.flags = O_RDONLY; break; case T_FIXNUM: o.flags = FIX2INT(flags); break; case T_BIGNUM: o.flags = NUM2INT(flags); break; default: rb_raise(rb_eArgError, "flags must be an Integer"); } switch (TYPE(mode)) { case T_NIL: o.mode = 0666; break; case T_FIXNUM: o.mode = FIX2INT(mode); break; case T_BIGNUM: o.mode = NUM2INT(mode); break; default: rb_raise(rb_eArgError, "mode must be an Integer"); } retry: fd = (int)rb_thread_blocking_region(nogvl_open, &o, RUBY_UBF_IO, 0); if (fd == -1) { if (errno == EMFILE || errno == ENFILE || errno == ENOMEM) { rb_gc(); if (retried) rb_sys_fail(o.pathname); retried = 1; goto retry; } if (fd == -1) { int saved_errno = errno; if (!st_lookup(errno2sym, (st_data_t)errno, &rv)) { errno = saved_errno; rb_sys_fail(o.pathname); } return rv; } } rv = rb_funcall(klass, id_for_fd, 1, INT2FIX(fd)); set_file_path(rv, pathname); return rv; }