indexing
	description: "The FILE protocol"
	legal: "See notice at end of class."
	status: "See notice at end of class."
	date: "$Date: 2006-05-08 15:57:22 -0700 (Mon, 08 May 2006) $"
	revision: "$Revision: 58769 $"

class interface
	FILE_PROTOCOL

create 
	make (addr: like address)
			-- Create protocol.
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			address_exists: addr /= Void
		ensure -- from DATA_RESOURCE
			address_set: address = addr

feature -- Access

	address: FILE_URL
			-- Associated address

	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)

	hash_code: INTEGER_32
			-- Hash function
			-- (from DATA_RESOURCE)
		ensure -- from HASHABLE
			good_hash_value: Result >= 0

	last_packet: STRING_8
			-- Last packet read
			-- (from DATA_RESOURCE)

	location: STRING_8
			-- Location of resource
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			address_exists: address /= Void

	mode: INTEGER_32
			-- Current mode
			-- (from DATA_RESOURCE)

	port: INTEGER_32
			-- Port used by service
			-- (from DATA_RESOURCE)
		ensure -- from DATA_RESOURCE
			result_non_negative: Result >= 0

	proxy_host: STRING_8
			-- Name or address of proxy host
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			proxy_supported: is_proxy_supported
			proxy_used: is_proxy_used
		ensure -- from DATA_RESOURCE
			result_not_empty: Result /= Void and then not Result.is_empty

	proxy_port: INTEGER_32
			-- Port of proxy
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			proxy_supported: is_proxy_supported
			proxy_used: is_proxy_used
		ensure -- from DATA_RESOURCE
			result_non_negative: Result >= 0

	service: STRING_8
			-- Name of service
			-- (from DATA_RESOURCE)
	
feature -- Measurement

	bytes_transferred: INTEGER_32
			-- Number of transferred bytes

	count: INTEGER_32
			-- Size of data resource

	last_packet_size: INTEGER_32
			-- Size of last packet

	read_buffer_size: INTEGER_32
			-- Size of read buffer
	
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 resource equal to `other'?
			-- (from DATA_RESOURCE)
		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_exists: BOOLEAN
			-- Does address exist?

	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

	error: BOOLEAN
			-- Has an error occurred?
			-- (from DATA_RESOURCE)

	error_code: INTEGER_32
			-- Code of error
			-- (from DATA_RESOURCE)

	error_text (code: INTEGER_32): STRING_8
			-- Textual description of error
			-- (from DATA_RESOURCE_ERROR_CONSTANTS)
		require -- from DATA_RESOURCE_ERROR_CONSTANTS
			positive_code: code > 0

	has_packet: BOOLEAN
			-- Is there a packet available in last_packet?
			-- (from DATA_RESOURCE)

	is_count_valid: BOOLEAN is True
			-- Is value in count valid? (Answer: yes)

	is_hashable: BOOLEAN
			-- Are objects of current type hashable?
			-- (from DATA_RESOURCE)
		ensure -- from HASHABLE
			ok_if_not_default: Result implies (Current /= default)

	is_local: BOOLEAN is True
			-- Is protocol not networked? (Answer: yes)

	is_mode_set: BOOLEAN
			-- Has resource mode been set?
			-- (from DATA_RESOURCE)

	is_open: BOOLEAN
			-- Is resource open?

	is_packet_pending: BOOLEAN
			-- Can another packet currently be read out?

	is_proxy_supported: BOOLEAN
			-- Is proxy supported by resource?
			-- (from DATA_RESOURCE)

	is_proxy_used: BOOLEAN is False
			-- Does resource use a proxy? (Answer: no)

	is_readable: BOOLEAN
			-- Is it possible to open in read mode currently?
		ensure -- from DATA_RESOURCE
			mode_unchanged: mode = old mode

	is_writable: BOOLEAN
			-- Is it possible to open in write mode currently?
		ensure -- from DATA_RESOURCE
			mode_unchanged: mode = old mode

	read_mode: BOOLEAN
			-- Is read mode set?

	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))

	supports_multiple_transactions: BOOLEAN is False
			-- Does resource support multiple tranactions per connection?
			-- (Answer: no)

	timeout: INTEGER_32
			-- Connection timeout
			-- (from DATA_RESOURCE)

	transfer_initiated: BOOLEAN
			-- Has transfer being initiated.
			-- (from DATA_RESOURCE)

	valid_mode (n: INTEGER_32): BOOLEAN
			-- Is mode `n' valid?

	write_mode: BOOLEAN
			-- Is write mode set?
	
feature -- Status setting

	close
			-- Close.
		require -- from DATA_RESOURCE
			open: is_open
		ensure -- from DATA_RESOURCE
			closed: not is_open
			mode_unchanged: mode = old mode
			no_packet_available: not (has_packet and is_packet_pending)

	initiate_transfer
			-- Initiate transfer.
		require -- from DATA_RESOURCE
			no_error_occurred: not error
			mode_set: is_mode_set
			open: is_open
			not_initiated: not transfer_initiated
		ensure -- from DATA_RESOURCE
			failure_means_error: not transfer_initiated implies error

	open
			-- Open file resource.
		require -- from DATA_RESOURCE
			no_error_occurred: not error
			mode_set: is_mode_set
		ensure -- from DATA_RESOURCE
			no_packet_available: not (has_packet and is_packet_pending)
			initiated_flag_reset: not transfer_initiated
			failure_means_error: not is_open implies error
		ensure then
			counter_reset: bytes_transferred = 0

	reset_error
			-- Reset error.
			-- (from DATA_RESOURCE)
		ensure -- from DATA_RESOURCE
			error_reset: not error

	reset_overwrite_mode
			-- Switch on file overwrite mode on.

	reset_proxy
			-- Reset proxy information.
			-- (from DATA_RESOURCE)
		ensure -- from DATA_RESOURCE
			proxy_reset: not address.is_proxy_used

	reuse_connection (other: DATA_RESOURCE)
			-- Reuse connection of `other'.
		require -- from DATA_RESOURCE
			other_exists: other /= Void
			same_type: same_type (other)
			supports_multiple_transactions: supports_multiple_transactions and other.supports_multiple_transactions
			other_opened: other.is_open

	set_overwrite_mode
			-- Switch on file overwrite mode on.

	set_password (pw: STRING_8)
			-- Set password to `pw'.
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			password_accepted: address.is_password_accepted
			non_empty_password: pw /= Void and then not pw.is_empty

	set_port (port_no: INTEGER_32)
			-- Set port number to `port_no'.
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			closed: not is_open
			non_negative_port_number: port_no >= 0
		ensure -- from DATA_RESOURCE
			port_set: port = port_no

	set_proxy (host: STRING_8; port_no: INTEGER_32)
			-- Set proxy host to `host' and port to `port_no'.
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			proxy_supported: is_proxy_supported
			closed: not is_open
			non_empty_host: host /= Void and then not host.is_empty
			host_ok: address.proxy_host_ok (host)
			non_negative_port: port_no >= 0
		ensure -- from DATA_RESOURCE
			proxy_set: address.is_proxy_used

	set_proxy_information (pi: PROXY_INFORMATION)
			-- Set proxy information to `pi'.
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			proxy_supported: is_proxy_supported
		ensure -- from DATA_RESOURCE
			proxy_set: address.is_proxy_used

	set_read_buffer_size (n: INTEGER_32)
			-- Set size of read buffer.
		require -- from DATA_RESOURCE
			size_positive: n > 0
		ensure -- from DATA_RESOURCE
			buffer_size_set: read_buffer_size = n
		ensure then
			buffer_size_correct: buffer.count = read_buffer_size

	set_read_mode
			-- Set read mode.
		ensure -- from DATA_RESOURCE
			read_mode_set: read_mode

	set_timeout (n: INTEGER_32)
			-- Set connection timeout to `n'.
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			non_negative: n >= 0
		ensure -- from DATA_RESOURCE
			timeout_set: timeout = n

	set_username (un: STRING_8)
			-- Set username to `un'.
			-- (from DATA_RESOURCE)
		require -- from DATA_RESOURCE
			username_accepted: address.has_username
			non_empty_username: un /= Void and then not un.is_empty

	set_write_mode
			-- Set write mode.
		ensure -- from DATA_RESOURCE
			write_mode_set: write_mode
	
feature -- Removal

	dispose
			-- Clean up resource.
			-- (from DATA_RESOURCE)
	
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 -- Input

	read
			-- Read packet.
		require -- from DATA_RESOURCE
			no_error_occurred: not error
			open: is_open
			transfer_initated: transfer_initiated
			readable: is_readable
			positive_read_buffer_size: read_buffer_size > 0
			packet_pending: is_packet_pending
		ensure -- from DATA_RESOURCE
			packet_received: is_packet_pending implies last_packet_size > 0
			counter_correct: not error implies bytes_transferred = old bytes_transferred + last_packet_size
	
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)

	put (other: DATA_RESOURCE)
			-- Write out resource `other'.
		require -- from DATA_RESOURCE
			no_error_occurred: not (error and other.error)
			other_resource_exists: other /= Void
			resources_open: is_open and other.is_open
			writable: is_writable
			transfer_initated: transfer_initiated

	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)
	
invariant
		-- from DATA_RESOURCE
	address_assigned: address /= Void
	timeout_non_negative: timeout >= 0
	packet_constraint: not (has_packet xor last_packet /= Void)
	pending_constraint: is_packet_pending implies (is_open and is_readable and transfer_initiated)
	error_definition: error = (error_code /= 0)
	valid_count_constraint: count > 0 implies is_count_valid
	mode_constraint: is_mode_set = read_mode xor write_mode

		-- 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 FILE_PROTOCOL