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[Guile-commits] 01/05: Add "custom ports"
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From: |
Andy Wingo |
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Subject: |
[Guile-commits] 01/05: Add "custom ports" |
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Date: |
Tue, 30 May 2023 06:38:07 -0400 (EDT) |
wingo pushed a commit to branch wip-custom-ports
in repository guile.
commit df63fc5c1bed52b7e344fa8035e7beb4aa381150
Author: Andy Wingo <wingo@pobox.com>
AuthorDate: Sat May 27 21:51:57 2023 +0200
Add "custom ports"
Custom ports are a kind of port that exposes the C port type interface
directly to Scheme. In this way the full capability of C is available
to Scheme, and also the read and write functions can be tail-called from
Scheme (via port-read / port-write).
* libguile/custom-ports.c:
* libguile/custom-ports.h:
* module/ice-9/custom-ports.scm: New files.
* libguile/init.c:
* libguile/Makefile.am:
* am/bootstrap.am: Add to the build.
* doc/ref/api-io.texi: Update the manual.
---
am/bootstrap.am | 3 +-
doc/ref/api-io.texi | 428 +++++++++++++++++++++++++-----------------
libguile/Makefile.am | 8 +-
libguile/custom-ports.c | 188 +++++++++++++++++++
libguile/custom-ports.h | 29 +++
libguile/init.c | 4 +-
module/ice-9/custom-ports.scm | 167 ++++++++++++++++
7 files changed, 647 insertions(+), 180 deletions(-)
diff --git a/am/bootstrap.am b/am/bootstrap.am
index 53ee68315..ffa37095d 100644
--- a/am/bootstrap.am
+++ b/am/bootstrap.am
@@ -1,4 +1,4 @@
-## Copyright (C) 2009-2022 Free Software Foundation, Inc.
+## Copyright (C) 2009-2023 Free Software Foundation, Inc.
##
## This file is part of GNU Guile.
##
@@ -132,6 +132,7 @@ SOURCES = \
ice-9/control.scm \
ice-9/copy-tree.scm \
ice-9/curried-definitions.scm \
+ ice-9/custom-ports.scm \
ice-9/deprecated.scm \
ice-9/documentation.scm \
ice-9/eval-string.scm \
diff --git a/doc/ref/api-io.texi b/doc/ref/api-io.texi
index 86f83e85e..e6cb80394 100644
--- a/doc/ref/api-io.texi
+++ b/doc/ref/api-io.texi
@@ -1,7 +1,7 @@
@c -*-texinfo-*-
@c This is part of the GNU Guile Reference Manual.
@c Copyright (C) 1996, 1997, 2000, 2001, 2002, 2003, 2004, 2007, 2009,
-@c 2010, 2011, 2013, 2016, 2019, 2021 Free Software Foundation, Inc.
+@c 2010, 2011, 2013, 2016, 2019, 2021, 2023 Free Software Foundation, Inc.
@c See the file guile.texi for copying conditions.
@node Input and Output
@@ -20,7 +20,6 @@
* Port Types:: Types of port and how to make them.
* Venerable Port Interfaces:: Procedures from the last millenium.
* Using Ports from C:: Nice interfaces for C.
-* I/O Extensions:: Implementing new port types in C.
* Non-Blocking I/O:: How Guile deals with EWOULDBLOCK.
* BOM Handling:: Handling of Unicode byte order marks.
@end menu
@@ -1063,6 +1062,8 @@ initialized with the @var{port} argument.
* Custom Ports:: Ports whose implementation you control.
* Soft Ports:: An older version of custom ports.
* Void Ports:: Ports on nothing at all.
+* Low-Level Custom Ports:: Implementing new kinds of port.
+* Low-Level Custom Ports in C:: A C counterpart to make-custom-port.
@end menu
@@ -1548,6 +1549,253 @@ specifies the input/output modes for this port: see the
documentation for @code{open-file} in @ref{File Ports}.
@end deffn
+@node Low-Level Custom Ports
+@subsubsection Low-Level Custom Ports
+
+This section describes how to implement a new kind of port using Guile's
+lowest-level, most primitive interfaces. First, load the @code{(ice-9
+custom-ports)} module:
+
+@example
+(use-modules (ice-9 custom-ports))
+@end example
+
+Then to make a new port, call @code{make-custom-port}:
+
+@deffn {Scheme Procedure} make-custom-port @
+ [#:read] [#:write] @
+ [#:read-wait-fd] [#:write-wait-fd] [#:input-waiting?] @
+ [#:seek] [#:random-access?] [#:get-natural-buffer-sizes] @
+ [#:id] [#:print] @
+ [#:close] [#:close-on-gc?] @
+ [#:truncate] @
+ [#:encoding] [#:conversion-strategy]
+Make a new custom port.
+
+@xref{Encoding}, for more on @code{#:encoding} and
+@code{#:conversion-strategy}.
+@end deffn
+
+A port has a number of associated procedures and properties which
+collectively implement its behavior. Creating a new custom port mostly
+involves writing these procedures, which are passed as keyword arguments
+to @code{make-custom-port}.
+
+@deffn {Scheme Port Method} #:read port dst start count
+A port's @code{#:read} implementation fills read buffers. It should
+copy bytes to the supplied bytevector @var{dst}, starting at offset
+@var{start} and continuing for @var{count} bytes, and return the number
+of bytes that were read, or @code{#f} to indicate that reading any bytes
+would block.
+@end deffn
+
+@deffn {Scheme Port Method} #:write port src start count
+A port's @code{#:write} implementation flushes write buffers to the
+mutable store. It should write out bytes from the supplied bytevector
+@var{src}, starting at offset @var{start} and continuing for @var{count}
+bytes, and return the number of bytes that were written, or @code{#f} to
+indicate writing any bytes would block.
+@end deffn
+
+If @code{make-custom-port} is passed a @code{#:read} argument, the port
+will be an input port. Passing a @code{#:write} argument will make an
+output port, and passing both will make an input-output port.
+
+@deffn {Scheme Port Method} #:read-wait-fd port
+@deffnx {Scheme Port Method} #:write-wait-fd port
+If a port's @code{#:read} or @code{#:write} method returns @code{#f},
+that indicates that reading or writing would block, and that Guile
+should instead @code{poll} on the file descriptor returned by the port's
+@code{#:read-wait-fd} or @code{#:write-wait-fd} method, respectively,
+until the operation can complete. @xref{Non-Blocking I/O}, for a more
+in-depth discussion.
+
+These methods must be implemented if the @code{#:read} or @code{#:write}
+method can return @code{#f}, and should return a non-negative integer
+file descriptor. However they may be called explicitly by a user, for
+example to determine if a port may eventually be readable or writeable.
+If there is no associated file descriptor with the port, they should
+return @code{#f}. The default implementation returns @code{#f}.
+@end deffn
+
+@deffn {Scheme Port Method} #:input-waiting? port
+In rare cases it is useful to be able to know whether data can be read
+from a port. For example, if the user inputs @code{1 2 3} at the
+interactive console, after reading and evaluating @code{1} the console
+shouldn't then print another prompt before reading and evaluating
+@code{2} because there is input already waiting. If the port can look
+ahead, then it should implement the @code{#:input-waiting?} method,
+which returns @code{#t} if input is available, or @code{#f} reading the
+next byte would block. The default implementation returns @code{#t}.
+@end deffn
+
+@deffn {Scheme Port Method} #:seek port offset whence
+Set or get the current byte position of the port. Guile will flush read
+and/or write buffers before seeking, as appropriate. The @var{offset}
+and @var{whence} parameters are as for the @code{seek} procedure;
+@xref{Random Access}.
+
+The @code{#:seek} method returns the byte position after seeking. To
+query the current position, @code{#:seek} will be called with an
+@var{offset} of 0 and @code{SEEK_CUR} for @var{whence}. Other values of
+@var{offset} and/or @var{whence} will actually perform the seek. The
+@code{#:seek} method should throw an error if the port is not seekable,
+which is what the default implementation does.
+@end deffn
+
+@deffn {Scheme Port Method} #:truncate port
+Truncate the port data to be specified length. Guile will flush buffers
+beforehand, as appropriate. The default implementation throws an error,
+indicating that truncation is not supported for this port.
+@end deffn
+
+@deffn {Scheme Port Method} #:random-access? port
+Return @code{#t} if @var{port} is open for random access, or @code{#f}
+otherwise.
+
+@cindex random access
+Seeking on a random-access port with buffered input, or switching to
+writing after reading, will cause the buffered input to be discarded and
+Guile will seek the port back the buffered number of bytes. Likewise
+seeking on a random-access port with buffered output, or switching to
+reading after writing, will flush pending bytes with a call to the
+@code{write} procedure. @xref{Buffering}.
+
+Indicate to Guile that your port needs this behavior by returning true
+from your @code{#:random-access?} method. The default implementation of
+this function returns @code{#t} if the port has a @code{#:seek}
+implementation.
+@end deffn
+
+@deffn {Scheme Port Method} #:get-natural-buffer-sizes read-buf-size
write-buf-size
+Guile will internally attach buffers to ports. An input port always has
+a read buffer, and an output port always has a write buffer.
+@xref{Buffering}. A port buffer consists of a bytevector, along with
+some cursors into that bytevector denoting where to get and put data.
+
+Port implementations generally don't have to be concerned with
+buffering: a port type's @code{#:read} or @code{#:write} method will
+receive the buffer's bytevector as an argument, along with an offset and
+a length into that bytevector, and should then either fill or empty that
+bytevector. However in some cases, port implementations may be able to
+provide an appropriate default buffer size to Guile. For example file
+ports implement @code{#:get-natural-buffer-sizes} to let the operating
+system inform Guile about the appropriate buffer sizes for the
+particular file opened by the port.
+
+This method returns two values, corresponding to the natural read and
+write buffer sizes for the ports. The two parameters
+@var{read-buf-size} and @var{write-buf-size} are Guile's guesses for
+what sizes might be good. A custom @code{#:get-natural-buffer-sizes}
+method could override Guile's choices, or just pass them on, as the
+default implementation does.
+@end deffn
+
+@deffn {Scheme Port Method} #:print port out
+Called when the port @var{port} is written to @var{out}, e.g. via
+@code{(write port out)}.
+
+If @code{#:print} is not explicitly supplied, the default implementation
+prints something like @code{#<@var{mode}:@var{id} @var{address}>}, where
+@var{mode} is either @code{input}, @code{output}, or
+@code{input-output}, @var{id} comes from the @code{#:id} keyword
+argument (defaulting to @code{"custom-port"}), and @var{address} is a
+unique integer associated with the port.
+@end deffn
+
+@deffn {Scheme Port Method} #:close port
+Called when @var{port} is closed. It should release any
+explicitly-managed resources used by the port.
+@end deffn
+
+By default, ports that are garbage collected just go away without
+closing or flushing any buffered output. If your port type needs to
+release some external resource like a file descriptor, or needs to make
+sure that its internal buffers are flushed even if the port is collected
+while it was open, then pass @code{#:close-on-gc? #t} to
+@code{make-custom-port}. Note that in that case, the @code{#:close}
+method will probably be called on a separate thread.
+
+Note that calls to all of these methods can proceed in parallel and
+concurrently and from any thread up until the point that the port is
+closed. The call to @code{close} will happen when no other method is
+running, and no method will be called after the @code{close} method is
+called. If your port implementation needs mutual exclusion to prevent
+concurrency, it is responsible for locking appropriately.
+
+@node Low-Level Custom Ports in C
+@subsubsection Low-Level Custom Ports in C
+
+The @code{make-custom-port} procedure described in the previous section
+has similar functionality on the C level, though it is organized a bit
+differently.
+
+In C, the mechanism is that one creates a new @dfn{port type object}.
+The methods are then associated with the port type object instead of the
+port itself. The port type object is an opaque pointer allocated when
+defining the port type, which serves as a key into the port API.
+
+Ports themselves have associated @dfn{stream} values. The stream is a
+pointer controlled by the user, which is set when the port is created.
+Given a port, the @code{SCM_STREAM} macro returns its associated stream
+value, as a @code{scm_t_bits}. Note that your port methods are only
+ever called with ports of your type, so port methods can safely cast
+this value to the expected type. Contrast this to Scheme, which doesn't
+need access to the stream because the @code{make-custom-port} methods
+can be closures that share port-specific data directly.
+
+A port type is created by calling @code{scm_make_port_type}.
+
+@deftypefun scm_t_port_type* scm_make_port_type (char *name, size_t (*read)
(SCM port, SCM dst, size_t start, size_t count), size_t (*write) (SCM port, SCM
src, size_t start, size_t count))
+Define a new port type. The @var{name} parameter is like the
+@code{#:id} parameter to @code{make-custom-port}; and @var{read} and
+@var{write} are like @code{make-custom-port}'s @code{#:read} and
+@code{#:write}, except that they should return @code{(size_t)-1} if the
+read or write operation would block, instead of @code{#f}.
+@end deftypefun
+
+@deftypefun void scm_set_port_read_wait_fd (scm_t_port_type *type, int
(*wait_fd) (SCM port))
+@deftypefunx void scm_set_port_write_wait_fd (scm_t_port_type *type, int
(*wait_fd) (SCM port))
+@deftypefunx void scm_set_port_print (scm_t_port_type *type, int (*print) (SCM
port, SCM dest_port, scm_print_state *pstate))
+@deftypefunx void scm_set_port_close (scm_t_port_type *type, void (*close)
(SCM port))
+@deftypefunx void scm_set_port_needs_close_on_gc (scm_t_port_type *type, int
needs_close_p)
+@deftypefunx void scm_set_port_seek (scm_t_port_type *type, scm_t_off (*seek)
(SCM port, scm_t_off offset, int whence))
+@deftypefunx void scm_set_port_truncate (scm_t_port_type *type, void
(*truncate) (SCM port, scm_t_off length))
+@deftypefunx void scm_set_port_random_access_p (scm_t_port_type *type, int
(*random_access_p) (SCM port));
+@deftypefunx void scm_set_port_input_waiting (scm_t_port_type *type, int
(*input_waiting) (SCM port));
+@deftypefunx void scm_set_port_get_natural_buffer_sizes @
+ (scm_t_port_type *type, void (*get_natural_buffer_sizes) (SCM, size_t
*read_buf_size, size_t *write_buf_size))
+Port method definitions. @xref{Low-Level Custom Ports}, for more
+details on each of these methods.
+@end deftypefun
+
+Once you have your port type, you can create ports with
+@code{scm_c_make_port}, or @code{scm_c_make_port_with_encoding}.
+
+@deftypefun SCM scm_c_make_port_with_encoding (scm_t_port_type *type, unsigned
long mode_bits, SCM encoding, SCM conversion_strategy, scm_t_bits stream)
+@deftypefunx SCM scm_c_make_port (scm_t_port_type *type, unsigned long
mode_bits, scm_t_bits stream)
+Make a port with the given @var{type}. The @var{stream} indicates the
+private data associated with the port, which your port implementation
+may later retrieve with @code{SCM_STREAM}. The mode bits should include
+one or more of the flags @code{SCM_RDNG} or @code{SCM_WRTNG}, indicating
+that the port is an input and/or an output port, respectively. The mode
+bits may also include @code{SCM_BUF0} or @code{SCM_BUFLINE}, indicating
+that the port should be unbuffered or line-buffered, respectively. The
+default is that the port will be block-buffered. @xref{Buffering}.
+
+As you would imagine, @var{encoding} and @var{conversion_strategy}
+specify the port's initial textual encoding and conversion strategy.
+Both are symbols. @code{scm_c_make_port} is the same as
+@code{scm_c_make_port_with_encoding}, except it uses the default port
+encoding and conversion strategy.
+@end deftypefun
+
+At this point you may be wondering whether to implement your custom port
+type in C or Scheme. The answer is that probably you want to use
+Scheme's @code{make-custom-port}. The speed is similar between C and
+Scheme, and ports implemented in C have the disadvantage of not being
+suspendable. @xref{Non-Blocking I/O}.
+
@node Venerable Port Interfaces
@subsection Venerable Port Interfaces
@@ -1692,179 +1940,6 @@ second, the @code{scm_t_uint32*} buffer is a string in
the UTF-32
encoding. These routines will update the port's line and column.
@end deftypefn
-@node I/O Extensions
-@subsection Implementing New Port Types in C
-
-This section describes how to implement a new port type in C. Although
-ports support many operations, as a data structure they present an
-opaque interface to the user. To the port implementor, you have two
-pieces of information to work with: the port type, and the port's
-``stream''. The port type is an opaque pointer allocated when defining
-your port type. It is your key into the port API, and it helps you
-identify which ports are actually yours. The ``stream'' is a pointer
-you control, and which you set when you create a port. Get a stream
-from a port using the @code{SCM_STREAM} macro. Note that your port
-methods are only ever called with ports of your type.
-
-A port type is created by calling @code{scm_make_port_type}. Once you
-have your port type, you can create ports with @code{scm_c_make_port},
-or @code{scm_c_make_port_with_encoding}.
-
-@deftypefun scm_t_port_type* scm_make_port_type (char *name, size_t (*read)
(SCM port, SCM dst, size_t start, size_t count), size_t (*write) (SCM port, SCM
src, size_t start, size_t count))
-Define a new port type. The @var{name}, @var{read} and @var{write}
-parameters are initial values for those port type fields, as described
-below. The other fields are initialized with default values and can be
-changed later.
-@end deftypefun
-
-@deftypefun SCM scm_c_make_port_with_encoding (scm_t_port_type *type, unsigned
long mode_bits, SCM encoding, SCM conversion_strategy, scm_t_bits stream)
-@deftypefunx SCM scm_c_make_port (scm_t_port_type *type, unsigned long
mode_bits, scm_t_bits stream)
-Make a port with the given @var{type}. The @var{stream} indicates the
-private data associated with the port, which your port implementation
-may later retrieve with @code{SCM_STREAM}. The mode bits should include
-one or more of the flags @code{SCM_RDNG} or @code{SCM_WRTNG}, indicating
-that the port is an input and/or an output port, respectively. The mode
-bits may also include @code{SCM_BUF0} or @code{SCM_BUFLINE}, indicating
-that the port should be unbuffered or line-buffered, respectively. The
-default is that the port will be block-buffered. @xref{Buffering}.
-
-As you would imagine, @var{encoding} and @var{conversion_strategy}
-specify the port's initial textual encoding and conversion strategy.
-Both are symbols. @code{scm_c_make_port} is the same as
-@code{scm_c_make_port_with_encoding}, except it uses the default port
-encoding and conversion strategy.
-@end deftypefun
-
-The port type has a number of associate procedures and properties which
-collectively implement the port's behavior. Creating a new port type
-mostly involves writing these procedures.
-
-@table @code
-@item name
-A pointer to a NUL terminated string: the name of the port type. This
-property is initialized via the first argument to
-@code{scm_make_port_type}.
-
-@item read
-A port's @code{read} implementation fills read buffers. It should copy
-bytes to the supplied bytevector @code{dst}, starting at offset
-@code{start} and continuing for @code{count} bytes, returning the number
-of bytes read.
-
-@item write
-A port's @code{write} implementation flushes write buffers to the
-mutable store.
-It should write out bytes from the supplied bytevector @code{src},
-starting at offset @code{start} and continuing for @code{count} bytes,
-and return the number of bytes that were written.
-
-@item read_wait_fd
-@itemx write_wait_fd
-If a port's @code{read} or @code{write} function returns @code{(size_t)
--1}, that indicates that reading or writing would block. In that case
-to preserve the illusion of a blocking read or write operation, Guile's
-C port run-time will @code{poll} on the file descriptor returned by
-either the port's @code{read_wait_fd} or @code{write_wait_fd} function.
-Set using
-
-@deftypefun void scm_set_port_read_wait_fd (scm_t_port_type *type, int
(*wait_fd) (SCM port))
-@deftypefunx void scm_set_port_write_wait_fd (scm_t_port_type *type, int
(*wait_fd) (SCM port))
-@end deftypefun
-
-Only a port type which implements the @code{read_wait_fd} or
-@code{write_wait_fd} port methods can usefully return @code{(size_t) -1}
-from a read or write function. @xref{Non-Blocking I/O}, for more on
-non-blocking I/O in Guile.
-
-@item print
-Called when @code{write} is called on the port, to print a port
-description. For example, for a file port it may produce something
-like: @code{#<input: /etc/passwd 3>}. Set using
-
-@deftypefun void scm_set_port_print (scm_t_port_type *type, int (*print) (SCM
port, SCM dest_port, scm_print_state *pstate))
-The first argument @var{port} is the port being printed, the second
-argument @var{dest_port} is where its description should go.
-@end deftypefun
-
-@item close
-Called when the port is closed. It should free any resources used by
-the port. Set using
-
-@deftypefun void scm_set_port_close (scm_t_port_type *type, void (*close) (SCM
port))
-@end deftypefun
-
-By default, ports that are garbage collected just go away without
-closing. If your port type needs to release some external resource like
-a file descriptor, or needs to make sure that its internal buffers are
-flushed even if the port is collected while it was open, then mark the
-port type as needing a close on GC.
-
-@deftypefun void scm_set_port_needs_close_on_gc (scm_t_port_type *type, int
needs_close_p)
-@end deftypefun
-
-@item seek
-Set the current position of the port. Guile will flush read and/or
-write buffers before seeking, as appropriate.
-
-@deftypefun void scm_set_port_seek (scm_t_port_type *type, scm_t_off (*seek)
(SCM port, scm_t_off offset, int whence))
-@end deftypefun
-
-@item truncate
-Truncate the port data to be specified length. Guile will flush buffers
-before hand, as appropriate. Set using
-
-@deftypefun void scm_set_port_truncate (scm_t_port_type *type, void
(*truncate) (SCM port, scm_t_off length))
-@end deftypefun
-
-@item random_access_p
-Determine whether this port is a random-access port.
-
-@cindex random access
-Seeking on a random-access port with buffered input, or switching to
-writing after reading, will cause the buffered input to be discarded and
-Guile will seek the port back the buffered number of bytes. Likewise
-seeking on a random-access port with buffered output, or switching to
-reading after writing, will flush pending bytes with a call to the
-@code{write} procedure. @xref{Buffering}.
-
-Indicate to Guile that your port needs this behavior by returning a
-nonzero value from your @code{random_access_p} function. The default
-implementation of this function returns nonzero if the port type
-supplies a seek implementation.
-
-@deftypefun void scm_set_port_random_access_p (scm_t_port_type *type, int
(*random_access_p) (SCM port));
-@end deftypefun
-
-@item get_natural_buffer_sizes
-Guile will internally attach buffers to ports. An input port always has
-a read buffer and an output port always has a write buffer.
-@xref{Buffering}. A port buffer consists of a bytevector, along with
-some cursors into that bytevector denoting where to get and put data.
-
-Port implementations generally don't have to be concerned with
-buffering: a port type's @code{read} or @code{write} function will
-receive the buffer's bytevector as an argument, along with an offset and
-a length into that bytevector, and should then either fill or empty that
-bytevector. However in some cases, port implementations may be able to
-provide an appropriate default buffer size to Guile.
-
-@deftypefun void scm_set_port_get_natural_buffer_sizes @
- (scm_t_port_type *type, void (*get_natural_buffer_sizes) (SCM, size_t
*read_buf_size, size_t *write_buf_size))
-Fill in @var{read_buf_size} and @var{write_buf_size} with an appropriate
buffer size for this port, if one is known.
-@end deftypefun
-
-File ports implement a @code{get_natural_buffer_sizes} to let the
-operating system inform Guile about the appropriate buffer sizes for the
-particular file opened by the port.
-@end table
-
-Note that calls to all of these methods can proceed in parallel and
-concurrently and from any thread up until the point that the port is
-closed. The call to @code{close} will happen when no other method is
-running, and no method will be called after the @code{close} method is
-called. If your port implementation needs mutual exclusion to prevent
-concurrency, it is responsible for locking appropriately.
-
@node Non-Blocking I/O
@subsection Non-Blocking I/O
@@ -1914,7 +1989,8 @@ read or write from this file and the read or write
returns a result
indicating that more data can only be had by doing a blocking read or
write, Guile will block by polling on the socket's @code{read-wait-fd}
or @code{write-wait-fd}, to preserve the illusion of a blocking read or
-write. @xref{I/O Extensions} for more on those internal interfaces.
+write. @xref{Low-Level Custom Ports} for more on those internal
+interfaces.
So far we have just reproduced the status quo: the file descriptor is
non-blocking, but the operations on the port do block. To go farther,
diff --git a/libguile/Makefile.am b/libguile/Makefile.am
index 36b3ed502..eb971fb1c 100644
--- a/libguile/Makefile.am
+++ b/libguile/Makefile.am
@@ -1,6 +1,6 @@
## Process this file with Automake to create Makefile.in
##
-## Copyright (C) 1998-2004, 2006-2014, 2016-2022
+## Copyright (C) 1998-2004, 2006-2014, 2016-2023
## Free Software Foundation, Inc.
##
## This file is part of GUILE.
@@ -139,6 +139,7 @@ libguile_@GUILE_EFFECTIVE_VERSION@_la_SOURCES =
\
chooks.c \
control.c \
continuations.c \
+ custom-ports.c \
debug.c \
deprecated.c \
deprecation.c \
@@ -259,6 +260,7 @@ DOT_X_FILES = \
chars.x \
control.x \
continuations.x \
+ custom-ports.x \
debug.x \
deprecated.x \
deprecation.x \
@@ -366,6 +368,7 @@ DOT_DOC_FILES = \
chars.doc \
control.doc \
continuations.doc \
+ custom-ports.doc \
debug.doc \
deprecated.doc \
deprecation.doc \
@@ -530,7 +533,8 @@ uninstall-hook:
## compile, since they are #included. So instead we list them here.
## Perhaps we can deal with them normally once the merge seems to be
## working.
-noinst_HEADERS = elf.h \
+noinst_HEADERS = custom-ports.h \
+ elf.h \
integers.h \
intrinsics.h \
quicksort.i.c \
diff --git a/libguile/custom-ports.c b/libguile/custom-ports.c
new file mode 100644
index 000000000..ee1fe9e02
--- /dev/null
+++ b/libguile/custom-ports.c
@@ -0,0 +1,188 @@
+/* Copyright 2023
+ Free Software Foundation, Inc.
+
+ This file is part of Guile.
+
+ Guile 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.
+
+ Guile 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 Guile. If not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "boolean.h"
+#include "eval.h"
+#include "extensions.h"
+#include "gsubr.h"
+#include "modules.h"
+#include "numbers.h"
+#include "ports-internal.h"
+#include "syscalls.h"
+#include "values.h"
+#include "variable.h"
+#include "version.h"
+
+#include "custom-ports.h"
+
+
+#define FOR_EACH_METHOD_EXCEPT_READ_WRITE(M) \
+ M(print, "print") \
+ M(read_wait_fd, "read-wait-fd") \
+ M(write_wait_fd, "write-wait-fd") \
+ M(seek, "seek") \
+ M(close, "close") \
+ M(get_natural_buffer_sizes, "get-natural-buffer-sizes") \
+ M(random_access_p, "random-access?") \
+ M(input_waiting, "input-waiting?") \
+ M(truncate, "truncate")
+
+#define FOR_EACH_METHOD(M) \
+ FOR_EACH_METHOD_EXCEPT_READ_WRITE(M) \
+ M(read, "read") \
+ M(write, "write")
+
+#define DEF_VAR(c_name, scm_name) static SCM c_name##_var;
+FOR_EACH_METHOD(DEF_VAR)
+#undef DEF_VAR
+
+static int custom_port_print (SCM exp, SCM port, scm_print_state *pstate) {
+ SCM data = SCM_PACK (SCM_STREAM (exp));
+ scm_call_3 (scm_variable_ref (print_var), exp, data, port);
+ return 1;
+}
+
+static int custom_port_read_wait_fd (SCM port) {
+ SCM data = SCM_PACK (SCM_STREAM (port));
+ SCM res = scm_call_2 (scm_variable_ref (read_wait_fd_var), port, data);
+ return scm_is_false (res) ? -1 : scm_to_signed_integer (res, 0, INT_MAX);
+}
+
+static int custom_port_write_wait_fd (SCM port) {
+ SCM data = SCM_PACK (SCM_STREAM (port));
+ SCM res = scm_call_2 (scm_variable_ref (write_wait_fd_var), port, data);
+ return scm_is_false (res) ? -1 : scm_to_signed_integer (res, 0, INT_MAX);
+}
+
+static scm_t_off custom_port_seek (SCM port, scm_t_off offset, int whence) {
+ SCM data = SCM_PACK (SCM_STREAM (port));
+ return scm_to_off_t (scm_call_4 (scm_variable_ref (seek_var), port, data,
+ scm_from_off_t (offset),
+ scm_from_int (whence)));
+}
+
+static void custom_port_close (SCM port) {
+ SCM data = SCM_PACK (SCM_STREAM (port));
+ scm_call_2 (scm_variable_ref (close_var), port, data);
+}
+
+static void custom_port_get_natural_buffer_sizes (SCM port, size_t *read_size,
+ size_t *write_size) {
+ SCM data = SCM_PACK (SCM_STREAM (port));
+ SCM res = scm_call_4 (scm_variable_ref (get_natural_buffer_sizes_var),
+ port, data, scm_from_size_t (*read_size),
+ scm_from_size_t (*write_size));
+ *read_size = scm_to_size_t (scm_c_value_ref (res, 0));
+ *write_size = scm_to_size_t (scm_c_value_ref (res, 1));
+}
+
+static int custom_port_random_access_p (SCM port) {
+ SCM data = SCM_PACK (SCM_STREAM (port));
+ return scm_to_bool (scm_call_2 (scm_variable_ref (random_access_p_var),
+ port, data));
+}
+
+static int custom_port_input_waiting (SCM port) {
+ SCM data = SCM_PACK (SCM_STREAM (port));
+ return scm_to_bool (scm_call_2 (scm_variable_ref (input_waiting_var),
+ port, data));
+}
+
+static void custom_port_truncate (SCM port, scm_t_off length) {
+ SCM data = SCM_PACK (SCM_STREAM (port));
+ scm_call_3 (scm_variable_ref (truncate_var), port, data,
+ scm_from_off_t (length));
+}
+
+static scm_t_port_type *custom_port_type;
+static scm_t_port_type *custom_port_type_with_close_on_gc;
+
+SCM_DEFINE_STATIC (make_custom_port, "%make-custom-port", 6, 0, 0,
+ (SCM input_p, SCM output_p, SCM stream, SCM encoding,
+ SCM conversion_strategy, SCM close_on_gc_p),
+ "") {
+ long mode_bits = 0;
+ if (scm_is_true (input_p))
+ mode_bits |= SCM_RDNG;
+ if (scm_is_true (output_p))
+ mode_bits |= SCM_WRTNG;
+
+ scm_t_port_type *pt = scm_is_true (close_on_gc_p) ?
+ custom_port_type_with_close_on_gc : custom_port_type;
+
+ return scm_c_make_port_with_encoding (pt, mode_bits, encoding,
+ conversion_strategy,
+ SCM_UNPACK (stream));
+}
+
+SCM_DEFINE_STATIC (custom_port_data, "%custom-port-data", 1, 0, 0,
+ (SCM port),
+ "")
+#define FUNC_NAME s_custom_port_data
+{
+ SCM_ASSERT(SCM_PORT_TYPE (port) == custom_port_type
+ || SCM_PORT_TYPE (port) == custom_port_type_with_close_on_gc,
+ port, SCM_ARG1, "custom port");
+ return SCM_PACK (SCM_STREAM (port));
+}
+#undef FUNC_NAME
+
+static void
+scm_init_custom_ports (void)
+{
+#define RESOLVE_VAR(c_name, scm_name) \
+ c_name##_var = scm_c_lookup ("custom-port-" scm_name);
+ FOR_EACH_METHOD(RESOLVE_VAR);
+#undef RESOlVE_VAR
+
+ custom_port_type = scm_make_port_type ("custom-port", NULL, NULL);
+ custom_port_type_with_close_on_gc =
+ scm_make_port_type ("custom-port", NULL, NULL);
+
+#define INIT_PORT_TYPE(c_name, scm_name) \
+ scm_set_port_##c_name (custom_port_type, custom_port_##c_name); \
+ scm_set_port_##c_name (custom_port_type_with_close_on_gc, \
+ custom_port_##c_name);
+ FOR_EACH_METHOD_EXCEPT_READ_WRITE(INIT_PORT_TYPE);
+#undef INIT_PORT_TYPE
+
+ scm_set_port_scm_read (custom_port_type, scm_variable_ref (read_var));
+ scm_set_port_scm_write (custom_port_type, scm_variable_ref (write_var));
+ scm_set_port_scm_read (custom_port_type_with_close_on_gc,
+ scm_variable_ref (read_var));
+ scm_set_port_scm_write (custom_port_type_with_close_on_gc,
+ scm_variable_ref (write_var));
+
+ scm_set_port_needs_close_on_gc (custom_port_type_with_close_on_gc, 1);
+
+#include "custom-ports.x"
+}
+
+void
+scm_register_custom_ports (void)
+{
+ scm_c_register_extension ("libguile-" SCM_EFFECTIVE_VERSION,
+ "scm_init_custom_ports",
+ (scm_t_extension_init_func) scm_init_custom_ports,
+ NULL);
+}
diff --git a/libguile/custom-ports.h b/libguile/custom-ports.h
new file mode 100644
index 000000000..287a87837
--- /dev/null
+++ b/libguile/custom-ports.h
@@ -0,0 +1,29 @@
+#ifndef SCM_CUSTOM_PORTS_H
+#define SCM_CUSTOM_PORTS_H
+
+/* Copyright 2023
+ Free Software Foundation, Inc.
+
+ This file is part of Guile.
+
+ Guile 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.
+
+ Guile 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 Guile. If not, see
+ <https://www.gnu.org/licenses/>. */
+
+
+
+#include "libguile/scm.h"
+
+SCM_INTERNAL void scm_register_custom_ports (void);
+
+#endif /* SCM_CUSTOM_PORTS_H */
diff --git a/libguile/init.c b/libguile/init.c
index b0a39e6d4..da3d2f0b7 100644
--- a/libguile/init.c
+++ b/libguile/init.c
@@ -1,4 +1,4 @@
-/* Copyright 1995-2004,2006,2009-2014,2016-2020
+/* Copyright 1995-2004,2006,2009-2014,2016-2021,2023
Free Software Foundation, Inc.
This file is part of Guile.
@@ -52,6 +52,7 @@
#include "chars.h"
#include "continuations.h"
#include "control.h"
+#include "custom-ports.h"
#include "debug.h"
#ifdef GUILE_DEBUG_MALLOC
#include "debug-malloc.h"
@@ -373,6 +374,7 @@ scm_i_init_guile (void *base)
scm_bootstrap_programs ();
scm_bootstrap_vm ();
scm_register_atomic ();
+ scm_register_custom_ports ();
scm_register_fdes_finalizers ();
scm_register_foreign ();
scm_register_foreign_object ();
diff --git a/module/ice-9/custom-ports.scm b/module/ice-9/custom-ports.scm
new file mode 100644
index 000000000..ba50d238a
--- /dev/null
+++ b/module/ice-9/custom-ports.scm
@@ -0,0 +1,167 @@
+;;; custom-ports.scm --- Defining new ports in Scheme
+;;; Copyright (C) 2023 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 program. If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;;
+;;; Code:
+
+(define-module (ice-9 custom-ports)
+ #:use-module (ice-9 match)
+ #:use-module (ice-9 textual-ports)
+ #:use-module (srfi srfi-9)
+ #:declarative? #f ; Because of extension.
+ #:export (make-custom-port))
+
+;; Replaced by extension; here just to suppress warnings.
+(define %make-custom-port error)
+(define %custom-port-data error)
+
+(define-record-type <custom-port-data>
+ (make-custom-port-data print read write read-wait-fd write-wait-fd
+ seek close get-natural-buffer-sizes
+ random-access? input-waiting? truncate)
+ custom-port-data?
+ (print custom-port-data-print)
+ (read custom-port-data-read)
+ (write custom-port-data-write)
+ (read-wait-fd custom-port-data-read-wait-fd)
+ (write-wait-fd custom-port-data-write-wait-fd)
+ (seek custom-port-data-seek)
+ (close custom-port-data-close)
+ (get-natural-buffer-sizes custom-port-data-get-natural-buffer-sizes)
+ (random-access? custom-port-data-random-access?)
+ (input-waiting? custom-port-data-input-waiting?)
+ (truncate custom-port-data-truncate))
+
+(define-syntax define-custom-port-dispatcher
+ (lambda (stx)
+ (define (prefixed-name prefix suffix)
+ (datum->syntax suffix (symbol-append prefix (syntax->datum suffix))))
+ (syntax-case stx ()
+ ((_ stem arg ...)
+ (with-syntax ((accessor (prefixed-name 'custom-port-data- #'stem))
+ (dispatcher (prefixed-name 'custom-port- #'stem)))
+ #'(define (dispatcher port data arg ...)
+ ((accessor data) port arg ...)))))))
+
+;; These bindings are captured by the extension.
+(define (custom-port-read port bv start count)
+ ((custom-port-data-read (%custom-port-data port)) port bv start count))
+(define (custom-port-write port bv start count)
+ ((custom-port-data-write (%custom-port-data port)) port bv start count))
+(define-custom-port-dispatcher print out-port)
+(define-custom-port-dispatcher read-wait-fd)
+(define-custom-port-dispatcher write-wait-fd)
+(define-custom-port-dispatcher seek offset whence)
+(define-custom-port-dispatcher close)
+(define-custom-port-dispatcher get-natural-buffer-sizes read-size write-size)
+(define-custom-port-dispatcher random-access?)
+(define-custom-port-dispatcher input-waiting?)
+(define-custom-port-dispatcher truncate length)
+
+
+(eval-when (load)
+ (load-extension (string-append "libguile-" (effective-version))
+ "scm_init_custom_ports"))
+
+(define* (make-default-print #:key (id "custom-port"))
+ (lambda (port out-port)
+ (define mode
+ (cond
+ ((port-closed? port) "closed:")
+ ((input-port? port) (if (output-port? port) "input-output:" "input:"))
+ ((output-port? port) "output:")
+ (else "bogus:")))
+ (put-string out-port "#<")
+ (put-string out-port mode)
+ (put-string out-port id)
+ (put-string out-port " ")
+ (put-string out-port (number->string (object-address port) 16))
+ (put-string out-port ">")))
+
+(define (default-read-wait-fd port) #f)
+(define (default-write-wait-fd port) #f)
+
+(define (default-seek port offset whence)
+ (error "custom port did not define a seek method" port))
+
+(define (default-close port) (values))
+
+(define (default-get-natural-buffer-sizes port read-buf-size write-buf-size)
+ (values read-buf-size write-buf-size))
+
+(define (make-default-random-access? seek)
+ (if seek
+ (lambda (port) #t)
+ (lambda (port) #f)))
+
+(define (default-input-waiting? port) #t)
+(define (default-truncate port length)
+ (error "custom port did not define a truncate method" port))
+
+(define* (make-custom-port
+ #:key
+ read
+ write
+ (read-wait-fd default-read-wait-fd)
+ (input-waiting? (and read default-input-waiting?))
+ (write-wait-fd default-write-wait-fd)
+ (seek #f)
+ (random-access? #f)
+ (close #f)
+ (get-natural-buffer-sizes default-get-natural-buffer-sizes)
+ (id "custom-port")
+ (print (make-default-print #:id id))
+ (truncate default-truncate)
+ (encoding (string->symbol (fluid-ref %default-port-encoding)))
+ (conversion-strategy (fluid-ref %default-port-conversion-strategy))
+ (close-on-gc? #f))
+ "Create a custom port whose behavior is determined by the methods passed
+as keyword arguments. Supplying a @code{#:read} method will make an input
+port, passing @code{#:write} will make an output port, and passing them
+both will make an input/output port.
+
+See the manual for full documentation on the semantics of these
+methods."
+ (define (canonicalize-encoding encoding)
+ (match encoding
+ (#f 'ISO-8859-1)
+ ((or 'ISO-8859-1 'UTF-8
+ 'UTF-16 'UTF-16LE 'UTF-16BE
+ 'UTF-32 'UTF-32LE 'UTF-32BE) encoding)
+ ((? symbol?)
+ (string->symbol (string-upcase (symbol->string encoding))))))
+ (define (canonicalize-conversion-strategy conversion-strategy)
+ (match encoding
+ ('escape 'escape)
+ ('substitute 'substitute)
+ (_ 'error)))
+ (let ((seek (or seek default-seek))
+ (close (or close default-close))
+ (random-access? (or random-access?
+ (if seek (lambda (_) #t) (lambda (_) #f))))
+ (close-on-gc? (and close close-on-gc?)))
+ (define data
+ (make-custom-port-data print read write read-wait-fd write-wait-fd
+ seek close get-natural-buffer-sizes
+ random-access? input-waiting? truncate))
+ (unless (or read write)
+ (error "Must have at least one I/O method (#:read and #:write)"))
+ (%make-custom-port (->bool read) (->bool write) data
+ (canonicalize-encoding encoding)
+ (canonicalize-conversion-strategy conversion-strategy)
+ close-on-gc?)))
- [Guile-commits] branch wip-custom-ports updated (9df5a8dfb -> 233846379), Andy Wingo, 2023/05/30
- [Guile-commits] 02/05: Rewrite custom binary ports in Scheme, in terms of custom ports, Andy Wingo, 2023/05/30
- [Guile-commits] 03/05: Use custom binary output ports for make-chunked-output-port, Andy Wingo, 2023/05/30
- [Guile-commits] 01/05: Add "custom ports",
Andy Wingo <=
- [Guile-commits] 04/05: Rewrite soft ports in Scheme, Andy Wingo, 2023/05/30
- [Guile-commits] 05/05: Implement R6RS custom textual ports, Andy Wingo, 2023/05/30