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guile/libguile/rw.c
Andy Wingo 8399e7af51 Generic port facility provides buffering uniformly 
* libguile/ports.h (struct scm_t_port_buffer): New data type.
  (struct scm_t_port): Refactor to use port buffers instead of
  implementation-managed read and write pointers.  Add "read_buffering"
  member.
  (SCM_INITIAL_PUTBACK_BUF_SIZE, SCM_READ_BUFFER_EMPTY_P): Remove.
  (scm_t_ptob_descriptor): Rename "fill_input" function to "read", and
  take a port buffer, returning void.  Likewise "write" takes a port
  buffer and returns void.  Remove "end_input"; instead if there is
  buffered input and rw_random is true, then there must be a seek
  function, so just seek back if needed.  Remove "flush"; instead all
  calls to the "write" function implicitly include a "flush", since the
  buffering happens in the generic port code now.  Remove "setvbuf", but
  add "get_natural_buffer_sizes"; instead the generic port code can
  buffer any port.
  (scm_make_port_type): Adapt to read and write prototype changes.
  (scm_set_port_flush, scm_set_port_end_input, scm_set_port_setvbuf):
  Remove.
  (scm_slow_get_byte_or_eof_unlocked)
  (scm_slow_get_peek_or_eof_unlocked): Remove; the slow path is to call
  scm_fill_input.
  (scm_set_port_get_natural_buffer_sizes): New function.
  (scm_c_make_port_buffer): New internal function.
  (scm_port_non_buffer): Remove.  This was a function for
  implementations that is no longer needed.  Instead open with BUF0 or
  use (setvbuf port 'none).
  (scm_fill_input, scm_fill_input_unlocked): Return the filled port
  buffer.
  (scm_get_byte_or_eof_unlocked, scm_peek_byte_or_eof_unlocked): Adapt
  to changes in buffering and EOF management.
* libguile/ports.c: Adapt to port interface changes.
  (initialize_port_buffers): New function, using the port mode flags to
  set up appropriate initial buffering for all ports.
  (scm_c_make_port_with_encoding): Create port buffers here instead of
  delegating to implementations.
  (scm_close_port): Flush the port if needed instead of delegating to
  the implementation.
* libguile/filesys.c (set_element): Adapt to buffering changes.
* libguile/fports.c (fport_get_natural_buffer_sizes): New function,
  replacing scm_fport_buffer_add.
  (fport_write, fport_read): Update to let the generic ports code do the
  buffering.
  (fport_flush, fport_end_input): Remove.
  (fport_close): Don't flush in a dynwind; that's the core ports' job.
  (scm_make_fptob): Adapt.
* libguile/ioext.c (scm_redirect_port): Adapt to buffering changes.
* libguile/poll.c (scm_primitive_poll): Adapt to buffering changes.
* libguile/ports-internal.h (struct scm_port_internal): Remove
  pending_eof flag; this is now set on the read buffer.
* libguile/r6rs-ports.c (struct bytevector_input_port): New type.  The
  new buffering arrangement means that there's now an intermediate
  buffer between the bytevector and the user of the port; this could
  lead to a perf degradation, but on the other hand there are some other
  speedups enabled by the buffering refactor, so probably the memcpy
  cost is dwarfed by the cost of the other parts of the ports
  machinery.
  (make_bytevector_input_port, bytevector_input_port_read):
  (bytevector_input_port_seek, initialize_bytevector_input_ports): Adapt
  to new buffering arrangement.
  (struct custom_binary_port): Remove read buffer, as Guile handles that
  now.
  (custom_binary_input_port_setvbuf): Remove; now handled by Guile.
  (make_custom_binary_input_port, custom_binary_input_port_read)
  (initialize_custom_binary_input_ports): Adapt.
  (scm_get_bytevector_some): Adapt to new EOF management.
  (scm_t_bytevector_output_port_buffer): Hold on to the underlying port,
  so we can flush it if it's open.
  (make_bytevector_output_port, bytevector_output_port_write):
  (bytevector_output_port_seek): Adapt.
  (bytevector_output_port_procedure): Flush the port as appropriate, so
  that we get all the bytes.
  (make_custom_binary_output_port, custom_binary_output_port_write):
  Adapt.
  (make_transcoded_port): Don't muck with buffering.
  (transcoded_port_write): Simply forward the write to the underlying
  port.
  (transcoded_port_read): Likewise.
  (transcoded_port_close): No need to flush.
  (initialize_transcoded_ports): Adapt.
* libguile/read.c (scm_i_scan_for_encoding): Adapt to buffering
  changes.
* libguile/rw.c (scm_write_string_partial): Adapt to buffering changes.
* libguile/strports.c: Adapt to the fact that we don't manage the
  buffer.  Probably room for speed improvements here...
* libguile/vports.c (soft_port_get_natural_buffer_sizes): New function.
  Adapt the rest of the file for the new buffering regime.
* test-suite/tests/r6rs-ports.test ("8.2.10 Output ports"): Custom
  binary output ports need to be flushed before you can rely on the
  write! procedure having been called.  Add necessary flush-port
  invocations.
  ("8.2.6  Input and output ports"): Transcoded ports now have an
  internal buffer by default.  This test checks that the characters are
  transcoded one at a time, so to do that, call setvbuf on the
  transcoded port to remove the buffer.
* test-suite/tests/web-client.test (run-with-http-transcript): Fix for
  different flushing regime on soft ports.  (The vestigial flush
  procedure is now called after each write, which is not what the test
  was expecting.)
* test-suite/standalone/test-scm-c-read.c: Update for changes to the C
  interface for defining port types.
* doc/ref/api-io.texi (Ports): Update to discuss buffering in a generic
  way, and to remove a hand-wavey paragraph describing string ports as
  "interesting and powerful".
  (Reading, Writing): Remove placeholder comments.  Document
  `scm_lfwrite'.
  (Buffering): New section.
  (File Ports): Link to buffering.
  (I/O Extensions): Join subnodes into parent and describe new API,
  including buffering API.
* doc/ref/posix.texi (Ports and File Descriptors): Link to buffering.
  Remove unread-char etc, as they are documented elsewhere.
  (Pipes, Network Sockets and Communication): Link to buffering.
2016-04-06 19:21:44 +02:00

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/* Copyright (C) 2001, 2006, 2009, 2011, 2014 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 3 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
/* This is the C part of the (ice-9 rw) module. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <errno.h>
#include <string.h>
#include "libguile/_scm.h"
#include "libguile/fports.h"
#include "libguile/ports.h"
#include "libguile/root.h"
#include "libguile/rw.h"
#include "libguile/strings.h"
#include "libguile/validate.h"
#include "libguile/modules.h"
#include "libguile/strports.h"
#include <unistd.h>
#ifdef HAVE_IO_H
#include <io.h>
#endif
#if defined (EAGAIN)
#define SCM_MAYBE_EAGAIN || errno == EAGAIN
#else
#define SCM_MAYBE_EAGAIN
#endif
#if defined (EWOULDBLOCK)
#define SCM_MAYBE_EWOULDBLOCK || errno == EWOULDBLOCK
#else
#define SCM_MAYBE_EWOULDBLOCK
#endif
/* MAYBE there is EAGAIN way of defining this macro but now I EWOULDBLOCK. */
#define SCM_EBLOCK(errno) \
(0 SCM_MAYBE_EAGAIN SCM_MAYBE_EWOULDBLOCK)
SCM_DEFINE (scm_read_string_x_partial, "read-string!/partial", 1, 3, 0,
(SCM str, SCM port_or_fdes, SCM start, SCM end),
"Read characters from a port or file descriptor into a\n"
"string @var{str}. A port must have an underlying file\n"
"descriptor --- a so-called fport. This procedure is\n"
"scsh-compatible and can efficiently read large strings.\n"
"It will:\n\n"
"@itemize\n"
"@item\n"
"attempt to fill the entire string, unless the @var{start}\n"
"and/or @var{end} arguments are supplied. i.e., @var{start}\n"
"defaults to 0 and @var{end} defaults to\n"
"@code{(string-length str)}\n"
"@item\n"
"use the current input port if @var{port_or_fdes} is not\n"
"supplied.\n"
"@item\n"
"return fewer than the requested number of characters in some\n"
"cases, e.g., on end of file, if interrupted by a signal, or if\n"
"not all the characters are immediately available.\n"
"@item\n"
"wait indefinitely for some input if no characters are\n"
"currently available,\n"
"unless the port is in non-blocking mode.\n"
"@item\n"
"read characters from the port's input buffers if available,\n"
"instead from the underlying file descriptor.\n"
"@item\n"
"return @code{#f} if end-of-file is encountered before reading\n"
"any characters, otherwise return the number of characters\n"
"read.\n"
"@item\n"
"return 0 if the port is in non-blocking mode and no characters\n"
"are immediately available.\n"
"@item\n"
"return 0 if the request is for 0 bytes, with no\n"
"end-of-file check.\n"
"@end itemize")
#define FUNC_NAME s_scm_read_string_x_partial
{
char *dest;
size_t offset;
long read_len;
long chars_read = 0;
int fdes;
{
size_t last;
SCM_VALIDATE_STRING (1, str);
scm_i_get_substring_spec (scm_i_string_length (str),
start, &offset, end, &last);
read_len = last - offset;
}
if (scm_is_integer (port_or_fdes))
fdes = scm_to_int (port_or_fdes);
else
{
SCM port = (SCM_UNBNDP (port_or_fdes)?
scm_current_input_port () : port_or_fdes);
SCM_VALIDATE_OPFPORT (2, port);
SCM_VALIDATE_INPUT_PORT (2, port);
/* if there's anything in the port buffers, use it, but then
don't touch the file descriptor. otherwise the
"return immediately if something is available" rule may
be violated. */
str = scm_i_string_start_writing (str);
dest = scm_i_string_writable_chars (str) + offset;
chars_read = scm_take_from_input_buffers (port, dest, read_len);
scm_i_string_stop_writing ();
fdes = SCM_FPORT_FDES (port);
}
if (chars_read == 0 && read_len > 0) /* don't confuse read_len == 0 with
EOF. */
{
str = scm_i_string_start_writing (str);
dest = scm_i_string_writable_chars (str) + offset;
SCM_SYSCALL (chars_read = read (fdes, dest, read_len));
scm_i_string_stop_writing ();
if (chars_read == -1)
{
if (SCM_EBLOCK (errno))
chars_read = 0;
else
SCM_SYSERROR;
}
else if (chars_read == 0)
{
scm_remember_upto_here_1 (str);
return SCM_BOOL_F;
}
}
scm_remember_upto_here_1 (str);
return scm_from_long (chars_read);
}
#undef FUNC_NAME
SCM_DEFINE (scm_write_string_partial, "write-string/partial", 1, 3, 0,
(SCM str, SCM port_or_fdes, SCM start, SCM end),
"Write characters from a string @var{str} to a port or file\n"
"descriptor. A port must have an underlying file descriptor\n"
"--- a so-called fport. This procedure is\n"
"scsh-compatible and can efficiently write large strings.\n"
"It will:\n\n"
"@itemize\n"
"@item\n"
"attempt to write the entire string, unless the @var{start}\n"
"and/or @var{end} arguments are supplied. i.e., @var{start}\n"
"defaults to 0 and @var{end} defaults to\n"
"@code{(string-length str)}\n"
"@item\n"
"use the current output port if @var{port_of_fdes} is not\n"
"supplied.\n"
"@item\n"
"in the case of a buffered port, store the characters in the\n"
"port's output buffer, if all will fit. If they will not fit\n"
"then any existing buffered characters will be flushed\n"
"before attempting\n"
"to write the new characters directly to the underlying file\n"
"descriptor. If the port is in non-blocking mode and\n"
"buffered characters can not be flushed immediately, then an\n"
"@code{EAGAIN} system-error exception will be raised (Note:\n"
"scsh does not support the use of non-blocking buffered ports.)\n"
"@item\n"
"write fewer than the requested number of\n"
"characters in some cases, e.g., if interrupted by a signal or\n"
"if not all of the output can be accepted immediately.\n"
"@item\n"
"wait indefinitely for at least one character\n"
"from @var{str} to be accepted by the port, unless the port is\n"
"in non-blocking mode.\n"
"@item\n"
"return the number of characters accepted by the port.\n"
"@item\n"
"return 0 if the port is in non-blocking mode and can not accept\n"
"at least one character from @var{str} immediately\n"
"@item\n"
"return 0 immediately if the request size is 0 bytes.\n"
"@end itemize")
#define FUNC_NAME s_scm_write_string_partial
{
const char *src;
scm_t_off write_len;
int fdes;
{
size_t offset;
size_t last;
SCM_VALIDATE_STRING (1, str);
src = scm_i_string_chars (str);
scm_i_get_substring_spec (scm_i_string_length (str),
start, &offset, end, &last);
src += offset;
write_len = last - offset;
}
if (write_len == 0)
return SCM_INUM0;
if (scm_is_integer (port_or_fdes))
fdes = scm_to_int (port_or_fdes);
else
{
SCM port = (SCM_UNBNDP (port_or_fdes)?
scm_current_output_port () : port_or_fdes);
scm_t_port_buffer *write_buf;
SCM_VALIDATE_OPFPORT (2, port);
SCM_VALIDATE_OUTPUT_PORT (2, port);
write_buf = SCM_PTAB_ENTRY (port)->write_buf;
/* Filling the last character in the buffer would require a
flush. */
if (write_len < write_buf->size - write_buf->end)
{
scm_c_write_unlocked (port, src, write_len);
return scm_from_long (write_len);
}
scm_flush_unlocked (port);
fdes = SCM_FPORT_FDES (port);
}
{
long rv;
SCM_SYSCALL (rv = write (fdes, src, write_len));
if (rv == -1)
{
if (SCM_EBLOCK (errno))
rv = 0;
else
SCM_SYSERROR;
}
scm_remember_upto_here_1 (str);
return scm_from_long (rv);
}
}
#undef FUNC_NAME
SCM
scm_init_rw_builtins ()
{
#include "libguile/rw.x"
return SCM_UNSPECIFIED;
}
void
scm_init_rw ()
{
scm_c_define_gsubr ("%init-rw-builtins", 0, 0, 0, scm_init_rw_builtins);
}
/*
Local Variables:
c-file-style: "gnu"
End:
*/
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