    indexing
    	description: "A medium poller for asynchronous IO on IO_MEDIUMs"
    	legal: "See notice at end of class."
    	status: "See notice at end of class."
    	date: "$Date: 2006-01-22 18:25:44 -0800 (Sun, 22 Jan 2006) $"
    	revision: "$Revision: 56675 $"

    class interface
    	MEDIUM_POLLER

    create
    	make
    			-- Create poller for multi-event polling.

    	make_read_only
    			-- Create poller for read events only.

    	make_write_only
    			-- Create poller for write events only.

    	make_exception_only
    			-- Create poller for exception events only.

    feature -- Initialization

    	make
    			-- Create poller for multi-event polling.

    	make_exception_only
    			-- Create poller for exception events only.

    	make_read_only
    			-- Create poller for read events only.

    	make_write_only
    			-- Create poller for write events only.

    feature -- Access

    	generating_type: STRING_8
    			-- Name of current object's generating type
    			-- (type of which it is a direct instance)
    			-- (from ANY)

    	generator: STRING_8
    			-- Name of current object's generating class
    			-- (base class of the type of which it is a direct instance)
    			-- (from ANY)

    feature -- Comparison

    	frozen deep_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void
    			-- or attached to isomorphic object structures?
    			-- (from ANY)
    		ensure -- from ANY
    			shallow_implies_deep: standard_equal (some, other) implies Result
    			both_or_none_void: (some = Void) implies (Result = (other = Void))
    			same_type: (Result and (some /= Void)) implies some.same_type (other)
    			symmetric: Result implies deep_equal (other, some)

    	frozen equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void or attached
    			-- to objects considered equal?
    			-- (from ANY)
    		ensure -- from ANY
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.is_equal (other))

    	is_equal (other: like Current): BOOLEAN
    			-- Is `other' attached to an object considered
    			-- equal to current object?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			symmetric: Result implies other.is_equal (Current)
    			consistent: standard_is_equal (other) implies Result

    	frozen standard_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void or attached to
    			-- field-by-field identical objects of the same type?
    			-- Always uses default object comparison criterion.
    			-- (from ANY)
    		ensure -- from ANY
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.standard_is_equal (other))

    	frozen standard_is_equal (other: like Current): BOOLEAN
    			-- Is `other' attached to an object of the same type
    			-- as current object, and field-by-field identical to it?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			same_type: Result implies same_type (other)
    			symmetric: Result implies other.standard_is_equal (Current)

    feature -- Status report

    	address_in_use: BOOLEAN
    			-- Address is in use by another socket.
    			-- (from SOCKET_RESOURCES)

    	address_not_readable: BOOLEAN
    			-- Unreadable address
    			-- (from SOCKET_RESOURCES)

    	already_bound: BOOLEAN
    			-- Socket has already been bound.
    			-- (from SOCKET_RESOURCES)

    	bad_socket_handle: BOOLEAN
    			-- Socket descriptor is bad.
    			-- (from SOCKET_RESOURCES)

    	conforms_to (other: ANY): BOOLEAN
    			-- Does type of current object conform to type
    			-- of `other' (as per Eiffel: The Language, chapter 13)?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void

    	connect_in_progress: BOOLEAN
    			-- Call to connect returned on a non-blocking socket.
    			-- (from SOCKET_RESOURCES)

    	connection_refused: BOOLEAN
    			-- Connection is refused (possibly due to security).
    			-- (from SOCKET_RESOURCES)

    	dtable_full: BOOLEAN
    			-- Descriptor table is full
    			-- (from SOCKET_RESOURCES)

    	error: STRING_8
    			-- Output a related error message.
    			-- (from SOCKET_RESOURCES)

    	error_number: INTEGER_32
    			-- Returned error number
    			-- (from SOCKET_RESOURCES)

    	expired_socket: BOOLEAN
    			-- Socket connection has expired.
    			-- (from SOCKET_RESOURCES)

    	invalid_address: BOOLEAN
    			-- Address is not valid.
    			-- (from SOCKET_RESOURCES)

    	invalid_socket_handle: BOOLEAN
    			-- Socket descriptor is not valid.
    			-- (from SOCKET_RESOURCES)

    	network: BOOLEAN
    			-- Socket failed due to network problems.
    			-- (from SOCKET_RESOURCES)

    	no_buffers: BOOLEAN
    			-- No more buffers available
    			-- (from SOCKET_RESOURCES)

    	no_permission: BOOLEAN
    			-- No permission is given to user for this socket.
    			-- (from SOCKET_RESOURCES)

    	not_connected: BOOLEAN
    			-- Socket is not connect.
    			-- (from SOCKET_RESOURCES)

    	protected_address: BOOLEAN
    			-- No access to this address is allowed.
    			-- (from SOCKET_RESOURCES)

    	protocol_not_supported: BOOLEAN
    			-- Protocol is not supported on this platform.
    			-- (from SOCKET_RESOURCES)

    	same_type (other: ANY): BOOLEAN
    			-- Is type of current object identical to type of `other'?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			definition: Result = (conforms_to (other) and other.conforms_to (Current))

    	socket_family_not_supported: BOOLEAN
    			-- Requested family is not supported.
    			-- (from SOCKET_RESOURCES)

    	socket_in_use: BOOLEAN
    			-- Socket is already in use.
    			-- (from SOCKET_RESOURCES)

    	socket_ok: BOOLEAN
    			-- No error
    			-- (from SOCKET_RESOURCES)

    	socket_would_block: BOOLEAN
    			-- Call to read, write, etc would have blocked.
    			-- (from SOCKET_RESOURCES)

    	zero_option: BOOLEAN
    			-- No options provided
    			-- (from SOCKET_RESOURCES)

    feature -- Duplication

    	copy (other: like Current)
    			-- Update current object using fields of object attached
    			-- to `other', so as to yield equal objects.
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    			type_identity: same_type (other)
    		ensure -- from ANY
    			is_equal: is_equal (other)

    	frozen deep_copy (other: like Current)
    			-- Effect equivalent to that of:
    			--		copy (`other' . deep_twin)
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			deep_equal: deep_equal (Current, other)

    	frozen deep_twin: like Current
    			-- New object structure recursively duplicated from Current.
    			-- (from ANY)
    		ensure -- from ANY
    			deep_equal: deep_equal (Current, Result)

    	frozen standard_copy (other: like Current)
    			-- Copy every field of `other' onto corresponding field
    			-- of current object.
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    			type_identity: same_type (other)
    		ensure -- from ANY
    			is_standard_equal: standard_is_equal (other)

    	frozen standard_twin: like Current
    			-- New object field-by-field identical to `other'.
    			-- Always uses default copying semantics.
    			-- (from ANY)
    		ensure -- from ANY
    			standard_twin_not_void: Result /= Void
    			equal: standard_equal (Result, Current)

    	frozen twin: like Current
    			-- New object equal to `Current'
    			-- twin calls copy; to change copying/twining semantics, redefine copy.
    			-- (from ANY)
    		ensure -- from ANY
    			twin_not_void: Result /= Void
    			is_equal: Result.is_equal (Current)

    feature -- Basic operations

    	frozen default: like Current
    			-- Default value of object's type
    			-- (from ANY)

    	frozen default_pointer: POINTER
    			-- Default value of type `POINTER'
    			-- (Avoid the need to write `p'.default for
    			-- some `p' of type `POINTER'.)
    			-- (from ANY)

    	default_rescue
    			-- Process exception for routines with no Rescue clause.
    			-- (Default: do nothing.)
    			-- (from ANY)

    	frozen do_nothing
    			-- Execute a null action.
    			-- (from ANY)

    feature

    	execute (max_des, time_out_msec: INTEGER_32)
    			-- Poll io_medium's whose descriptor is less than
    			-- `max_des' and process ready media.
    			-- If no medium is ready, wait the 'time_out..'
    			-- time before returning.
    		require
    			valid_number: max_des > 0

    	medium_select (number_to_check, time_out_msec: INTEGER_32): INTEGER_32
    			-- Check the multiplexing masks for the
    			-- read, write, and exception medium reception
    			-- and return the number of mediums waiting
    			-- after 'time_out...' time

    feature --  blocking features

    	set_wait
    			-- Set poller to block.
    		ensure
    			wait_set: wait

    	unset_wait
    			-- Set poller to return after timeout.
    		ensure
    			wait_not_set: not wait

    	wait: BOOLEAN
    			-- Poller blocks until event?
    			-- (otherwise, returns after timeout)

    feature -- Externals: flags for send, sendto recv and recvfrom socket calls

    	c_msgdontroute: INTEGER_32
    			-- Do not route message
    			-- (from SOCKET_RESOURCES)

    	c_oobmsg: INTEGER_32
    			-- Out of bound message
    			-- (from SOCKET_RESOURCES)

    	c_peekmsg: INTEGER_32
    			-- Peek message
    			-- (from SOCKET_RESOURCES)

    feature -- Output

    	io: STD_FILES
    			-- Handle to standard file setup
    			-- (from ANY)

    	out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of tagged_out.
    			-- (from ANY)

    	print (some: ANY)
    			-- Write terse external representation of `some'
    			-- on standard output.
    			-- (from ANY)

    	frozen tagged_out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of out.
    			-- (from ANY)

    feature -- Platform

    	operating_environment: OPERATING_ENVIRONMENT
    			-- Objects available from the operating system
    			-- (from ANY)

    feature -- booleans to decide whether to include each mask in the select call

    	ignore_exception: BOOLEAN
    			-- Is Exception mask ignored?

    	ignore_read: BOOLEAN
    			-- Is read mask ignored?

    	ignore_write: BOOLEAN
    			-- Is write mask ignored?

    	set_exception
    			-- Set exception mask to be looked up.
    		ensure
    			exception_used: not ignore_exception

    	set_ignore_exception
    			--  Ignore exception mask.
    		ensure
    			exception_not_used: ignore_exception

    	set_ignore_read
    			-- Ignore read mask.
    		ensure
    			read_not_used: ignore_read

    	set_ignore_write
    			-- Ignore write mask.
    		ensure
    			write_not_used: ignore_write

    	set_read
    			-- Set read mask to be looked up.
    		ensure
    			read_used: not ignore_read

    	set_write
    			-- Set write mask to be looked up.
    		ensure
    			write_used: not ignore_write

    feature -- commands to be executed

    	exception_command_list: ARRAY [POLL_COMMAND]
    			-- List of poll commands to be called
    			-- when their medium is selected for exception event.

    	put_exception_command (a_command: POLL_COMMAND)
    			-- Set `a_command' to be called when exception event
    			-- is selected on its io_medium.
    		require
    			valid_command: a_command /= Void
    			not_empty_medium: a_command.active_medium /= Void
    		ensure
    			command_added: exception_command_list.has (a_command)

    	put_read_command (a_command: POLL_COMMAND)
    			-- Set `a_command' to be called when read event is
    			-- selected on its io_medium.
    		require
    			valid_command: a_command /= Void
    			not_empty_medium: a_command.active_medium /= Void
    		ensure
    			command_added: read_command_list.has (a_command)

    	put_write_command (a_command: POLL_COMMAND)
    			-- Set `a_command' to be called when write event is
    			-- selected on its io_medium.
    		require
    			valid_command: a_command /= Void
    			not_empty_medium: a_command.active_medium /= Void
    		ensure
    			command_added: write_command_list.has (a_command)

    	read_command_list: ARRAY [POLL_COMMAND]
    			-- List of poll commands to be called
    			-- when their medium is selected for read event.

    	remove_associated_exception_command (s: IO_MEDIUM)
    			-- Remove command associated with medium `s' from
    			-- exception registered media.
    		require
    			has_command: exception_command_list.upper >= s.handle
    		ensure
    			command_removed: exception_command_list.item (s.handle) = Void

    	remove_associated_read_command (s: IO_MEDIUM)
    			-- Remove command associated with medium `s' from
    			-- read registered media.
    		require
    			has_command: read_command_list.upper >= s.handle
    		ensure
    			command_removed: read_command_list.item (s.handle) = Void

    	remove_associated_write_command (s: IO_MEDIUM)
    			-- Remove command associated with medium `s' from
    			-- write registered media.
    		require
    			has_command: write_command_list.upper >= s.handle
    		ensure
    			command_removed: write_command_list.item (s.handle) = Void

    	remove_exception_command (a_command: POLL_COMMAND)
    			-- Remove `a_command' from exception registered media.
    		require
    			has_command: exception_command_list.has (a_command)
    		ensure
    			command_removed: not exception_command_list.has (a_command)

    	remove_read_command (a_command: POLL_COMMAND)
    			-- Remove `a_command' from read registered media.
    		require
    			valid_command: a_command /= Void
    			has_command: read_command_list.has (a_command)
    			not_empty_medium: a_command.active_medium /= Void
    		ensure
    			command_removed: not read_command_list.has (a_command)

    	remove_write_command (a_command: POLL_COMMAND)
    			-- Remove `a_command' from write registered media.
    		require
    			has_command: write_command_list.has (a_command)
    		ensure
    			command_removed: not write_command_list.has (a_command)

    	write_command_list: ARRAY [POLL_COMMAND]
    			-- List of poll commands to be called
    			-- when their medium is selected for write event.

    feature -- medium masks

    	except_mask: POLL_MASK
    			-- Exception mask used by medium select

    	last_except_mask: POLL_MASK
    			-- Exception mask returned by medium select

    	last_read_mask: POLL_MASK
    			-- Read mask returned by medium select

    	last_write_mask: POLL_MASK
    			-- Write mask returned by medium select

    	read_mask: POLL_MASK
    			-- Read mask used by medium select

    	write_mask: POLL_MASK
    			-- Write mask used by medium select.

    feature -- process set commands

    	process_selected (number_of_selected: INTEGER_32)
    			-- Process commands for ready media.
    		require
    			valid_number: number_of_selected > 0

    invariant
    		-- from ANY
    	reflexive_equality: standard_is_equal (Current)
    	reflexive_conformance: conforms_to (Current)

    indexing
    	copyright: "Copyright (c) 1984-2006, Eiffel Software and others"
    	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
    	source: "[
    		Eiffel Software
    		356 Storke Road, Goleta, CA 93117 USA
    		Telephone 805-685-1006, Fax 805-685-6869
    		Website http://www.eiffel.com
    		Customer support http://support.eiffel.com
    	]"

    end -- class MEDIUM_POLLER