-- FTPProtocol.mesa, Edit: HGM July 31, 1980 11:05 PM
-- Copyright Xerox Corporation 1979, 1980
DIRECTORY
FTPDefs,
FTPPrivateDefs,
String USING [AppendChar, AppendString, EquivalentString, StringBoundsFault],
Storage USING [Node, String, Free, FreeStringNil];
FTPProtocol: PROGRAM
-- import list
IMPORTS String, Storage, FTPPrivateDefs
-- export list
EXPORTS FTPPrivateDefs
-- share list
SHARES FTPDefs =
BEGIN OPEN FTPDefs, FTPPrivateDefs;
-- **********************! Constants !***********************
ftpsystem: POINTER TO FTPSystem = LocateFtpSystemObject[];
-- **********************! Command/Response Shorthands !***********************
PutGetVersion: PUBLIC PROCEDURE [ftper: FTPer, version: Byte] =
BEGIN
-- Note: Obtains local command string from ftper.outputString;
-- returns remote command string in ftper.inputString.
-- local variables
mark, code: Byte;
-- send IAmVersion command and EOC
PutCommandAndEOC[ftper, markIAmVersion, version];
-- receive echoing IAmVersion command and EOC in response
[mark, code] ← GetCommandAndEOC[ftper];
IF mark # markIAmVersion THEN Abort[illegalProtocolSequence];
-- verify protocol version number
IF code # version THEN Abort[protocolVersionMismatch];
END;
GetAnswerAndEOC: PUBLIC PROCEDURE [ftper: FTPer] RETURNS [answer: BOOLEAN] =
BEGIN
-- local variables
mark, code: Byte;
-- receive command and EOC
[mark, code] ← GetCommandAndEOC[ftper];
-- decode answer
SELECT mark FROM
markYes => answer ← TRUE;
markNo => answer ← FALSE;
ENDCASE => Abort[illegalProtocolSequence];
END;
GetYesAndEOC: PUBLIC PROCEDURE [ftper: FTPer] =
BEGIN
-- receive Yes command
GetSpecificCommand[ftper, markYes];
-- receive EOC
GetEOC[ftper];
END;
GetSpecificCommand: PUBLIC PROCEDURE [ftper: FTPer, specificMark: Byte] =
BEGIN
-- Note: If a No command is encountered, flushes the EOC that follows
-- and uses No's parameters as the basis for an abort.
-- local variables
mark, code: Byte;
-- receive command
[mark, code] ← GetCommand[ftper];
-- verify that expected command received
SELECT mark FROM
specificMark => NULL;
markNo =>
BEGIN
-- receive EOC
GetEOC[ftper];
-- abort
AbortWithExplanation[CodeToSignal[code], ftper.inputString];
END;
ENDCASE => Abort[illegalProtocolSequence];
END;
PutCommandAndEOC: PUBLIC PROCEDURE [ftper: FTPer, mark, code: Byte] =
BEGIN
-- send command
PutCommand[ftper, mark, code];
-- send EOC
PutEOC[ftper];
END;
GetCommandAndEOC: PUBLIC PROCEDURE [ftper: FTPer] RETURNS [mark, code: Byte] =
BEGIN
-- receive command
[mark, code] ← GetCommand[ftper];
-- receive EOC
GetEOC[ftper];
END;
PutEOC: PUBLIC PROCEDURE [ftper: FTPer] =
BEGIN OPEN ftper;
-- Note: Forces transmission.
-- send EOC
PutCommand[ftper, markEndOfCommand, 0];
-- force its transmission
communicationPrimitives.ForceOutput[communicationSystem, connection];
END;
GetEOC: PUBLIC PROCEDURE [ftper: FTPer] =
BEGIN
-- receive EOC
GetSpecificCommand[ftper, markEndOfCommand];
END;
-- **********************! Command/Response Primitives !***********************
PutCommand: PUBLIC PROCEDURE [ftper: FTPer, mark, code: Byte] =
BEGIN OPEN ftper;
-- Note: Obtains command string, whenever appropriate, from ftper.outputString.
-- local variables
codeAppropriate, stringAppropriate: BOOLEAN;
-- trace change of direction (if any) and mark
IF tracing THEN TraceOut[ftper, mark];
-- send and classify mark
communicationPrimitives.ProduceDiscontinuity[communicationSystem, connection];
communicationPrimitives.SendByte[communicationSystem, connection, mark];
[codeAppropriate, stringAppropriate] ← ClassifyCommand[mark];
-- send code if any (which is traced by PutCharacter)
IF codeAppropriate THEN PutCharacter[ftper, code];
-- send string if any (which is traced by PutString)
IF stringAppropriate AND outputString.length # 0 THEN
BEGIN PutString[ftper, outputString]; outputString.length ← 0; END;
END;
GetCommand: PUBLIC PROCEDURE [ftper: FTPer] RETURNS [mark, code: Byte] =
BEGIN OPEN ftper;
-- Note: Flushes comments; returns zero if no code;
-- returns command string, whenever appropriate, in ftper.inputString.
-- local variables
settledForNone: BOOLEAN;
codeAppropriate, stringAppropriate: BOOLEAN;
-- trace change of direction (if any)
IF tracing THEN TraceIn[ftper];
-- initialize code to none
code ← 0;
-- receive commands until non-comment encountered
mark ← markComment;
WHILE mark = markComment DO
-- flush until next mark
[, settledForNone] ← communicationPrimitives.ReceiveByte[
communicationSystem, connection, TRUE];
IF ~settledForNone THEN SkipThingsFaster[ftper];
communicationPrimitives.ConsumeDiscontinuity[
communicationSystem, connection];
-- receive and classify mark
mark ← GetCharacter[ftper, FALSE];
[codeAppropriate, stringAppropriate] ← ClassifyCommand[mark];
-- receive code if any
IF codeAppropriate THEN code ← GetCharacter[ftper, FALSE];
-- receive string if any
IF stringAppropriate THEN GetString[ftper, inputString, 0];
ENDLOOP;
END;
-- Used to skip to the end of a file if we abort during a transfer
SkipThingsFaster: PROCEDURE [ftper: FTPer] =
BEGIN OPEN ftper;
trash: ARRAY [0..100) OF WORD;
bpo: BytePointerObject;
DO
bpo ← [@trash, FALSE, 2*100];
communicationPrimitives.ReceiveBytes[
communicationSystem, connection, @bpo, FALSE];
IF bpo.count # 0 THEN EXIT;
ENDLOOP;
END;
ClassifyCommand: PROCEDURE [mark: Byte]
RETURNS [codeAppropriate, stringAppropriate: BOOLEAN] =
BEGIN
-- initialize classification
codeAppropriate ← stringAppropriate ← FALSE;
-- interpret mark
SELECT mark FROM
~IN [markMinimum..markMaximum] => Abort[functionNotImplemented];
markYes, markNo, markIAmVersion, markMailboxException =>
codeAppropriate ← stringAppropriate ← TRUE;
markComment, markYouAreUser, markAbort => stringAppropriate ← TRUE;
ENDCASE;
END;
PutPropertyList: PUBLIC PROCEDURE [ftper: FTPer, propertyList: PropertyList] =
BEGIN
-- PutProperty procedure
PutProperty: PROCEDURE [property: Property, value: STRING] =
BEGIN
-- local constants
encodedValue: STRING = [maxStringLength];
-- local variables
i: CARDINAL;
-- send left delimiter
PutCharacter[ftper, propertyLeftDelimiter];
-- send property name
PutString[ftper, ftpsystem.propertyNames[property]];
-- send separator
PutCharacter[ftper, propertyNameValueSeparator];
-- precede reserved characters with escape
FOR i IN [0..value.length) DO
SELECT value[i] FROM
propertyLeftDelimiter, propertyRightDelimiter, propertyEscape =>
String.AppendChar[encodedValue, propertyEscape];
ENDCASE;
String.AppendChar[encodedValue, value[i]];
ENDLOOP;
-- send property value
PutString[ftper, encodedValue];
-- send right delimiter
PutCharacter[ftper, propertyRightDelimiter];
END;
-- local variables
property: Property;
-- send left delimiter
PutCharacter[ftper, propertyListLeftDelimiter];
-- send properties
FOR property IN Property DO
IF propertyList[property] # NIL THEN
PutProperty[property, propertyList[property]];
ENDLOOP;
-- send right delimiter
PutCharacter[ftper, propertyListRightDelimiter];
END;
GetPropertyList: PUBLIC PROCEDURE [ftper: FTPer, propertyList: PropertyList] =
BEGIN
-- Note: Caller may handle optional property list case
-- by intercepting protocolParameterListMissing.
-- GetProperty procedure
GetProperty: PROCEDURE [value: STRING] RETURNS [property: Property] =
BEGIN OPEN ftper;
-- local constants
name: STRING = [maxStringLength];
-- local variables
character: CHARACTER;
-- left delimiter received by GetPropertyList
-- receive property name and separator
GetString[ftper, name, propertyNameValueSeparator];
-- receive property value and right delimiter
value.length ← 0;
UNTIL (character ← GetCharacter[ftper, FALSE]) = propertyRightDelimiter DO
IF character = propertyEscape THEN character ← GetCharacter[ftper, FALSE];
String.AppendChar[
value, character ! String.StringBoundsFault => Abort[stringTooLong]];
ENDLOOP;
-- search for name among property names
FOR property IN Property DO
IF String.EquivalentString[name, ftpsystem.propertyNames[property]] THEN
RETURN;
ENDLOOP;
-- abort if not found
Abort[unrecognizedProtocolParameter];
END;
-- local constants
value: STRING = [maxStringLength];
-- local variables
property: Property;
-- initialize property list to empty
ResetPropertyList[propertyList];
-- receive left delimiter
IF GetCharacter[ftper, TRUE] # propertyListLeftDelimiter THEN
Abort[protocolParameterListMissing];
-- receive properties until right delimiter encountered
DO
SELECT GetCharacter[ftper, FALSE] FROM
propertyLeftDelimiter =>
IF propertyList[property ← GetProperty[value]] # NIL THEN
Abort[duplicateProtocolParameter]
ELSE WriteProperty[propertyList, property, value];
propertyListRightDelimiter => EXIT;
ENDCASE => Abort[illegalProtocolParameterList];
ENDLOOP;
END;
PutString: PUBLIC PROCEDURE [ftper: FTPer, string: STRING] =
BEGIN OPEN ftper;
-- local variables
bytePointerObject: BytePointerObject ← [@string.text, FALSE, string.length];
-- trace string
IF tracing THEN TraceString[ftper, string];
-- send string
communicationPrimitives.SendBytes[
communicationSystem, connection, @bytePointerObject];
END;
GetString: PUBLIC PROCEDURE [
ftper: FTPer, string: STRING, terminator: UNSPECIFIED] =
BEGIN OPEN ftper;
-- Note: Declaring terminator UNSPECIFIED admits both CHARACTER and Byte;
-- null teminator implies mark.
-- local constants
rathole: STRING = [maxStringLength];
-- local variables
byte: Byte;
character: CHARACTER;
bytePointerObject: BytePointerObject;
-- initialize string
IF string = NIL THEN string ← rathole ELSE string.length ← 0;
-- receive characters until terminating character encountered
IF terminator # 0 THEN
BEGIN
-- receive string and terminator
DO
[byte, ] ← communicationPrimitives.ReceiveByte[
communicationSystem, connection, FALSE];
IF (character ← LOOPHOLE[byte]) = terminator THEN EXIT;
String.AppendChar[
string, character ! String.StringBoundsFault => Abort[stringTooLong]];
ENDLOOP;
-- trace string and terminator
IF tracing THEN
BEGIN TraceString[ftper, string]; TraceCharacter[ftper, character]; END;
END
-- receive characters until mark encountered
ELSE
BEGIN
-- receive string
bytePointerObject ← [@string.text, FALSE, string.maxlength];
communicationPrimitives.ReceiveBytes[
communicationSystem, connection, @bytePointerObject, TRUE];
string.length ← string.maxlength - bytePointerObject.count;
-- trace string
IF tracing THEN TraceString[ftper, string];
-- abort if string too long
IF string.length = string.maxlength AND GetCharacter[ftper, TRUE] # 0 THEN
Abort[stringTooLong];
END;
END;
PutCharacter: PROCEDURE [ftper: FTPer, character: UNSPECIFIED] =
BEGIN OPEN ftper;
-- Note: Declaring character UNSPECIFIED admits both CHARACTER and Byte.
-- trace character
IF tracing THEN TraceCharacter[ftper, character];
-- send character
communicationPrimitives.SendByte[communicationSystem, connection, character];
END;
GetCharacter: PROCEDURE [ftper: FTPer, settleForNone: BOOLEAN]
RETURNS [character: UNSPECIFIED] =
BEGIN OPEN ftper;
-- Note: Declaring character UNSPECIFIED admits both CHARACTER and Byte;
-- returns null character if mark pending.
-- local variables
settledForNone: BOOLEAN;
-- receive character or discover mark pending
[character, settledForNone] ← communicationPrimitives.ReceiveByte[
communicationSystem, connection, settleForNone];
-- trace character or supply null character
IF settledForNone THEN character ← 0
ELSE IF tracing THEN TraceCharacter[ftper, character];
END;
-- **********************! Property List Primitives !***********************
CreatePropertyList: PUBLIC PROCEDURE RETURNS [propertyList: PropertyList] =
BEGIN
-- local variables
property: Property;
pointer: POINTER TO PropertyListObject;
-- allocate property list object
pointer ← Storage.Node[SIZE[PropertyListObject]];
propertyList ← DESCRIPTOR[pointer↑];
-- initialize property list to empty
FOR property IN Property DO propertyList[property] ← NIL; ENDLOOP;
END;
DestroyPropertyList: PUBLIC PROCEDURE [propertyList: PropertyList] =
BEGIN
-- release property list values
ResetPropertyList[propertyList];
-- release property list object
Storage.Free[BASE[propertyList]];
END;
CopyPropertyList: PUBLIC PROCEDURE [
srcPropertyList, dstPropertyList: PropertyList] =
BEGIN
-- local variables
property: Property;
-- copy property values
FOR property IN Property DO
WriteProperty[dstPropertyList, property, srcPropertyList[property]];
ENDLOOP;
END;
ResetPropertyList: PUBLIC PROCEDURE [propertyList: PropertyList] =
BEGIN
-- local variables
property: Property;
-- release property values and reset to NIL
FOR property IN Property DO
propertyList[property] ← Storage.FreeStringNil[propertyList[property]];
ENDLOOP;
END;
WriteProperty: PUBLIC PROCEDURE [
propertyList: PropertyList, property: Property, value: STRING] =
BEGIN
-- set property value to NIL
IF value = NIL OR value.length = 0 THEN
-- release current property value
propertyList[property] ← Storage.FreeStringNil[propertyList[property]]
-- set property value to string
ELSE
BEGIN
-- allocate string to hold new property value
IF propertyList[property] = NIL THEN
propertyList[property] ← Storage.String[value.length]
-- use current string if possible
ELSE
IF value.length > propertyList[property].maxlength THEN
BEGIN
propertyList[property] ← Storage.FreeStringNil[propertyList[property]];
propertyList[property] ← Storage.String[value.length];
END
ELSE propertyList[property].length ← 0;
-- record new property value
String.AppendString[propertyList[property], value];
END;
END;
EncodeBooleanProperty: PUBLIC PROCEDURE [boolean: BOOLEAN, property: STRING] =
BEGIN
-- Note: Defaults to FALSE.
-- encode boolean property
property.length ← 0;
IF boolean THEN String.AppendString[property, "Yes"L];
END;
DecodeBooleanProperty: PUBLIC PROCEDURE [property: STRING]
RETURNS [boolean: BOOLEAN] =
BEGIN
-- Note: Defaults to FALSE.
-- decode boolean property
SELECT TRUE FROM
(property = NIL), String.EquivalentString[property, "No"L] =>
boolean ← FALSE;
String.EquivalentString[property, "Yes"L] => boolean ← TRUE;
ENDCASE => Abort[illegalBooleanParameter];
END;
END. -- of FTPProtocol