NAME

src/io/io.c - Generic IO

DESCRIPTION

The Parrot IO subsystem uses a per-interpreter stack to provide a layer-based approach to IO. Each layer implements a subset of the ParrotIOLayerAPI vtable. To find an IO function, Parrot searches the layer stack downwards until it finds a non-NULL function pointer for that particular slot.

This file implements the generic functionality. Specific layers are in separate files: src/io/io_buf.c, src/io/io_stdio.c, src/io/io_unix.c, src/io/io_win32.c, and src/io/io_layers.c.

The ParrotIO PMC provides the class-based interface that is used in Parrot ops. The ParrotIO struct is defined in src/io/io_private.h.

Resource Functions

PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL PMC *new_io_pmc(PARROT_INTERP, NULLOK(ParrotIO *io)): Creates and returns a new ParrotIO PMC.
PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL STRING *PIO_make_io_string(PARROT_INTERP, NOTNULL(STRING **buf), size_t len): Creates a STRING* suitable for returning results from IO read functions. The passed in buf parameter can:; In the third case, the buffer or STRING must be able to hold the required amount of data. For cases 1 and 2, a NULL strstart tells this function to allocate the STRING memory.
PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL ParrotIO *PIO_new(PARROT_INTERP, SHIM(INTVAL iotype), INTVAL flags, INTVAL mode): Creates a new IO stream.; The values of flags and mode are set in the returned ParrotIO.; Currently iotype is unused.
PARROT_API void PIO_destroy(SHIM_INTERP, NOTNULL(PMC *pmc)): Destroys the IO stream. At the moment, this only frees the memory and removes the pointers from the PMC.
PARROT_API void PIO_init(PARROT_INTERP): Sets up the interpreter's layer stack and creates the STD* handles.; Called when creating an interpreter.
PARROT_API void PIO_finish(PARROT_INTERP): Closes the interpreter's IO resourses. Called during its interpreter destruction.
PARROT_API void PIO_internal_shutdown(SHIM_INTERP): IO system destructor, called on destruction of the last interpreter.
PARROT_API INTVAL PIO_init_stacks(PARROT_INTERP): Initializes the interpreter's default IO stack by pushing on the IO layers (OS-specific first).
PARROT_API INTVAL PIO_base_init(SHIM_INTERP, SHIM(ParrotIOLayer *l)): Init routine called once for each layer at interpreter creation time. This is similar to a Perl module INIT {} block.; This default implementation does nothing and returns 0.

Generic top-level `ParrotIO` interface

PARROT_API PARROT_WARN_UNUSED_RESULT INTVAL PIO_parse_open_flags(NULLOK(const char *flagstr)): Parses *flagstr for Perl-style file open mode flags (<, >, >>, +<, +>) and returns the combined generic bit flags.; The low level OS layers may then interpret the generic bits differently depending on platform.; XXX BD Should this be static?
PARROT_API INTVAL PIO_peek(PARROT_INTERP, NOTNULL(PMC *pmc), NOTNULL(STRING **buffer)): Iterates down the stack to the first layer implementing "Peek" API.
PARROT_API INTVAL PIO_pioctl(PARROT_INTERP, NOTNULL(PMC *pmc), INTVAL cmd, INTVAL arg): General purpose interface for manipulating IO objects and layer attributes.; Refer to the PIOCTL* values in include/parrot/io.h.; All set operations return 0 on success and a negative value on error. get operations use the return value as the value requested, but should always be >= 0. A negative value indicates an error. This may be too limited, but we will see. --Melvin
PARROT_API INTVAL PIO_setbuf(PARROT_INTERP, NOTNULL(PMC *pmc), size_t bufsize): Sets the buffer size for *pmc to bufsize. Returns 0 if the buffering was enabled.
PARROT_API INTVAL PIO_setlinebuf(PARROT_INTERP, NOTNULL(PMC *pmc)): Enables line buffering for *pmc. Returns 0 if line buffering was successfully set, or already enabled.
PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL PMC *PIO_open(PARROT_INTERP, NULLOK(ParrotIOLayer *layer), NOTNULL(const char *spath), NOTNULL(const char *sflags)): Creates and returns a ParrotIO PMC for *spath.
PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL PMC *PIO_fdopen(PARROT_INTERP, NULLOK(ParrotIOLayer *layer), PIOHANDLE fd, NOTNULL(const char *sflags)): Creates and returns a ParrotIO PMC for *spath on an existing, open file descriptor.; This is used particularly to initialize the STD* IO handles onto the OS IO handles (0, 1, 2).
PARROT_API INTVAL PIO_close(PARROT_INTERP, NULLOK(PMC *pmc)): Flushes, closes, and destroys the ParrotIO PMC *pmc.
PARROT_API void PIO_flush(PARROT_INTERP, NOTNULL(PMC *pmc)): Flushes the ParrotIO PMC *pmc.
PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL STRING *PIO_reads(PARROT_INTERP, NOTNULL(PMC *pmc), size_t len): Return a new STRING* holding up to len bytes.
PARROT_API PARROT_WARN_UNUSED_RESULT INTVAL PIO_read(PARROT_INTERP, NOTNULL(PMC *pmc), NOTNULL(char *buffer), size_t len): Reads up to len bytes from *pmc and copies them into *buffer.
PARROT_API PARROT_WARN_UNUSED_RESULT INTVAL PIO_write(PARROT_INTERP, NOTNULL(PMC *pmc), NOTNULL(const void *buffer), size_t len): Writes len bytes from *buffer to *pmc.
PARROT_API PARROT_WARN_UNUSED_RESULT PIOOFF_T PIO_seek(PARROT_INTERP, NOTNULL(PMC *pmc), PIOOFF_T offset, INTVAL w): Moves the read/write position of *pmc to offset bytes from the position indicated by w. Typically w will be 0 for the start of the file, 1 for the current position, and 2 for the end.
PARROT_API PARROT_WARN_UNUSED_RESULT PIOOFF_T PIO_tell(PARROT_INTERP, NOTNULL(PMC *pmc)): Returns the current read/write position of *pmc.
PARROT_API PARROT_WARN_UNUSED_RESULT INTVAL PIO_eof(SHIM_INTERP, NOTNULL(PMC *pmc)): Returns a boolean value indication whether *pmc's current read/write position is EOF.
PARROT_API INTVAL PIO_puts(PARROT_INTERP, NOTNULL(PMC *pmc), NOTNULL(const char *s)): Writes *s tp *pmc. C string version.
PARROT_API INTVAL PIO_putps(PARROT_INTERP, NOTNULL(PMC *pmc), NULLOK(STRING *s)): Writes *s to *pmc. Parrot string version.
PARROT_API INTVAL PIO_fprintf(PARROT_INTERP, NOTNULL(PMC *pmc), NOTNULL(const char *s), ...): Writes a C string format with varargs to *pmc.
PARROT_API INTVAL PIO_printf(PARROT_INTERP, NOTNULL(const char *s), ...): Writes a C string format with varargs to stdout.
PARROT_API INTVAL PIO_eprintf(NULLOK(PARROT_INTERP), NOTNULL(const char *s), ...): Writes a C string format with varargs to stderr.
PARROT_API PARROT_WARN_UNUSED_RESULT PIOHANDLE PIO_getfd(SHIM_INTERP, NOTNULL(PMC *pmc)): Returns *pmc's file descriptor, or 0 if it is not defined.

`PIO_STD*` Functions

PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL PMC *PIO_STDIN(PARROT_INTERP): Returns the ParrotIO PMC for stdin.
PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL PMC *PIO_STDOUT(PARROT_INTERP): Returns the ParrotIO PMC for stdout.
PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL PMC *PIO_STDERR(PARROT_INTERP): Returns the ParrotIO PMC for stderr.

DOD-related Functions

PARROT_API void Parrot_IOData_mark(PARROT_INTERP, NOTNULL(ParrotIOData *piodata)): Called from trace_active_PMCs() to mark the IO data live.

Offset Functions

These are used to create offsets for the seek op.

PIOOFF_T PIO_make_offset(INTVAL offset): Returns offset.
PIOOFF_T PIO_make_offset32(INTVAL hi, INTVAL lo): hi is shifted 32 bytes to the left and ored together with lo. This allows 64-bit seeks with only 32-bit INTVALS.
PIOOFF_T PIO_make_offset_pmc(PARROT_INTERP, NOTNULL(PMC *pmc)): Returns the return value of the get_integer vtable method on *pmc.

Networking Functions

PARROT_API INTVAL PIO_poll(PARROT_INTERP, NOTNULL(PMC *pmc), INTVAL which, INTVAL sec, INTVAL usec): Polls *pmc for the events in which every sec seconds + usec microseconds.
PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CANNOT_RETURN_NULL PMC *PIO_socket(PARROT_INTERP, INTVAL fam, INTVAL type, INTVAL proto): Creates and returns a socket using the specified address family, socket type, and protocol number. Check the returned PMC with a boolean test to see whether the socket was successfully created.
PARROT_API INTVAL PIO_recv(PARROT_INTERP, NOTNULL(PMC *pmc), NOTNULL(STRING **buf)): Receives a message from the connected socket *pmc in *buf. Returns -1 if it fails.
PARROT_API PARROT_WARN_UNUSED_RESULT INTVAL PIO_send(PARROT_INTERP, NOTNULL(PMC *pmc), NOTNULL(STRING *buf)): Sends the message *buf to the connected socket *pmc. Returns -1 if it cannot send the message.
PARROT_API INTVAL PIO_connect(PARROT_INTERP, NOTNULL(PMC *pmc), NOTNULL(STRING *address)): Connects *pmc to *address. Returns -1 on failure.
PARROT_API INTVAL PIO_bind(PARROT_INTERP, NOTNULL(PMC *pmc), NOTNULL(STRING *address)): Binds *pmc's socket to the local address and port specified by *address. Returns -1 on failure.
PARROT_API PARROT_WARN_UNUSED_RESULT INTVAL PIO_listen(PARROT_INTERP, NOTNULL(PMC *pmc), INTVAL backlog): Listens for new connections on socket *pmc. Returns -1 on failure.
PARROT_API PARROT_WARN_UNUSED_RESULT PARROT_CAN_RETURN_NULL PMC *PIO_accept(PARROT_INTERP, NOTNULL(PMC *pmc)): Accepts a new connection and returns a newly created ParrotIO socket. Returns NULL on failure.
PARROT_API PARROT_WARN_UNUSED_RESULT INTVAL PIO_isatty(SHIM_INTERP, NOTNULL(PMC *pmc)): Returns a boolean value indicating whether *pmc is a console/tty.

HISTORY

Initially written by Melvin Smith.

Some ideas and goals from Perl 5.7 and Nick Ing-Simmons' work.

TODO

Rework to use copy-on-write IO stacks rather than creating a new stack for each IO stream.

Add support for loadable layers in Parrot bytecode.

parrotcode: Generic IO
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