PFSCanonicalNamesImpl.mesa
Copyright Ó 1991 by Xerox Corporation. All rights reserved.
Carl Hauser, August 23, 1989 11:40:59 am PDT
Chauser, May 24, 1990 10:25 am PDT
Michael Plass, September 23, 1991 12:16 pm PDT
DIRECTORY
Ascii USING [NUL, SP, TAB],
Convert USING [CardFromRope, RopeFromCard],
IO USING [BreakProc, GetTokenRope, STREAM],
PFSBackdoor,
PFSNames,
PFSCanonicalNames,
Rope USING [Concat, Substr, Fetch, IsEmpty, Length];
PFSCanonicalNamesImpl: CEDAR PROGRAM
IMPORTS Convert, IO, Rope, PFSBackdoor, PFSNames
EXPORTS PFSCanonicalNames
SHARES PFSNames
~ BEGIN OPEN PFSNames;
Error: ERROR ~ CODE;
Unparsed: TYPE ~ RECORD [
canonicalUnparsing: ROPE ¬ NIL
];
UnparseName: PUBLIC PROC [name: PATH] RETURNS [fullFName: ROPE] ~ {
unparsed: REF Unparsed;
serverComponent: BOOL ¬ TRUE;
cproc: ComponentProc ~ {
fullFName ¬ Rope.Concat[fullFName, UnparseComponent[comp]];
IF serverComponent THEN {
IF NOT comp.name.len=0 THEN fullFName ¬ Rope.Concat[fullFName, ":"];
serverComponent ¬ FALSE;
}
};
sproc: SeparatorProc ~ {
IF NOT serverComponent THEN {
IF separatorPresent THEN fullFName ¬ Rope.Concat[fullFName, "/"];
}
ELSE {
IF NOT separatorPresent THEN serverComponent ¬ FALSE;
};
};
name ¬ PFSNames.NonNIL[name];
unparsed ¬ WITH name.GetUnparsingHint[] SELECT FROM
unp: REF Unparsed => unp,
ENDCASE => NIL;
IF unparsed#NIL THEN RETURN [unparsed.canonicalUnparsing];
Map[name, cproc, sproc];
};
UnparseComponent: PUBLIC PROC [component: Component] RETURNS [ROPE] ~ {
RETURN[Rope.Concat[
component.name.base.Substr[component.name.start, component.name.len], UnparseVersion[component.version]]];
};
UnparseVersion: PUBLIC PROC [version: Version] RETURNS [ROPE] ~ {
RETURN [ SELECT version.versionKind FROM
none => NIL,
lowest => "!L",
highest => "!H",
all => "!*",
numeric => Rope.Concat["!", Convert.RopeFromCard[version.version]],
ENDCASE => NIL
];
};
ParseName: PUBLIC PROC [name: ROPE] RETURNS [parsedName: PATH] ~ {
Canonical parsing.
absolute, directory: BOOL ¬ FALSE;
comps: LIST OF Component ¬ NIL;
IF name.IsEmpty[] THEN RETURN [NIL];
absolute ¬ name.Fetch[0]='/;
IF absolute THEN comps ¬ CONS[ [name~["", 0, 0]], comps ];
directory ¬ name.Fetch[name.Length[]-1]='/;
{
ENABLE Error => PFSBackdoor.ProduceError[invalidNameSyntax, Rope.Concat[name, " is syntactically invalid as a Unix-style file name"]];
pos: NAT ¬ IF absolute THEN 1 ELSE 0;
limit: NAT ¬ name.Length[];
firstComponent: BOOL ¬ TRUE;
ScanComponent: PROC [] RETURNS [] ~ {
nextComp: Component;
[nextComp, pos] ¬ ParseComponent[name, pos];
IF firstComponent AND NOT absolute THEN {
len: INT ¬ nextComp.name.len;
IF len > 0 THEN IF Rope.Fetch[nextComp.name.base, nextComp.name.start+len-1] = ': THEN {
absolute ¬ TRUE;
nextComp.name.len ¬ nextComp.name.len-1;
};
};
firstComponent ¬ FALSE;
comps ¬ CONS[nextComp, comps];
};
ScanSeparator: PROC [] RETURNS [] ~ {
IF name.Fetch[pos]#'/ THEN ERROR Error[];
pos ¬ pos+1;
};
DO
IF pos >= limit THEN EXIT;
ScanComponent[];
IF pos >= limit THEN EXIT;
ScanSeparator[];
ENDLOOP;
};
RETURN[ConstructName[components: comps, absolute: absolute, directory: directory, reverse: TRUE, unparsed: NEW[Unparsed ¬ [name]] ]];
};
ParseComponent: PUBLIC PROC [name: ROPE, first: NAT ¬ 0] RETURNS [component: Component ¬ [], next: NAT] ~ {
limit: NAT ¬ name.Length[];
next ¬ first;
DO
IF next >= limit THEN {
component.name ¬ [name, first, next-first];
EXIT;
};
SELECT name.Fetch[next] FROM
'! => {
component.name ¬ [name, first, next-first];
[component.version, next] ¬ ParseVersion[name, next];
EXIT;
};
'/ => {
component.name ¬ [name, first, next-first];
EXIT;
};
ENDCASE => next ¬ next+1;
ENDLOOP;
};
ParseVersion: PUBLIC PROC [v: ROPE, first: NAT ¬ 0] RETURNS [version: Version ¬ [none], next: NAT] ~ {
limit: NAT ¬ v.Length[];
next ¬ first;
IF next>=limit THEN RETURN;
IF v.Fetch[next]#'! THEN ERROR Error[];
next ¬ next+1;
IF next>=limit THEN RETURN;
SELECT v.Fetch[next] FROM
IN ['0..'9] => {
start: NAT ¬ next;
next ¬ next+1;
WHILE next < limit AND v.Fetch[next] IN ['0..'9] DO next ¬ next+1 ENDLOOP;
RETURN [ [numeric, Convert.CardFromRope[v.Substr[start, next-start]]], next ];
};
'H, 'h => RETURN[ [highest], next+1 ];
'L, 'l => RETURN[ [lowest], next+1 ];
'N, 'n => RETURN[ [next], next+1 ];
'* => RETURN[ [all], next+1 ];
ENDCASE => NULL;
ERROR Error[];
};
ParseNameFromStream: PUBLIC PROC [s: IO.STREAM] RETURNS [name: PATH] ~ {
A convenient way to read a whitespace-delimited name from a stream;
FileNameProc: IO.BreakProc ~ {
OPEN Ascii;
RETURN [ SELECT char FROM
NUL, SP, TAB => sepr,
ENDCASE => other ];
};
ropeName: ROPE ¬ IO.GetTokenRope[s, FileNameProc].token;
RETURN[ParseName[ropeName]];
};
END.