-- File: DBNamesImpl.mesa
-- last edited by:
  -- Cattell, July 5, 1983 5:00 pm
  -- Donahue, July 28, 1983 3:13 pm
  -- Willie-sue, February 22, 1983 4:08 pm

DIRECTORY
  DB,
  DBEnvironment,
  DBNames,
  NutOps,
  Rope,
  ViewerOps;
  
DBNamesImpl: CEDAR PROGRAM
  IMPORTS Rope, DB, DBEnvironment, NutOps

  EXPORTS DBNames =

  BEGIN OPEN Rope, DB;
  
  Separator: PUBLIC CHAR _ '!;
  
  Sep: ROPE = Rope.FromChar[Separator];
  
  EntityToName: PUBLIC PROC[ e: Entity, seg: DB.Segment _ NIL ] RETURNS[ name: ROPE ] = {
    IF NOT NutOps.IsSystemDomain[d: DomainOf[e]] THEN seg _ DB.SegmentOf[e];
    name _ Rope.Cat[ DB.GetSegmentInfo[seg].filePath,
                           Sep, NameOf[DomainOf[e]], Sep, NameOf[e] ]};
                           
  MakeName: PUBLIC PROC[seg: DB.Segment, d: Domain, eName: ROPE] RETURNS[name: ROPE] =
  { name _ Rope.Cat[GetSegmentInfo[seg].filePath, Sep, NameOf[d], Sep, eName]};
  
  NameToEntity: PUBLIC PROC[name: ROPE, create: BOOL _ FALSE] RETURNS[e: Entity] = {
    segName, domainName, entityName: ROPE;
    domain: Domain;
    segment: DB.Segment;
    [segName, domainName, entityName] _ DecomposeName[name];
    segment _ NutOps.AtomFromSegment[segName];
    -- check to make sure that this is the right segment for the entity
    IF NOT Rope.Equal[DB.GetSegmentInfo[segment].filePath, segName] THEN RETURN[NIL];
    domain _ DeclareDomain[ domainName, segment, Version[OldOnly] ! 
                 DBEnvironment.Error => CHECKED { domain _ NIL; CONTINUE } ];
    e _ IF domain = NIL THEN NIL
         ELSE FetchEntity[ domain, entityName, segment ];
    IF e = NIL AND domain # NIL AND create THEN
      e _ DeclareEntity[ domain, entityName ! DB.Error => CONTINUE ] };
                
  SegmentOf: PUBLIC PROC[ name: ROPE ] RETURNS[ segment: DB.Segment ] = {
    segNameLength: INT = Rope.Find[name, Sep];
    segName: ROPE = Rope.Substr[name, 0, segNameLength];
    RETURN[ NutOps.AtomFromSegment[ segName ] ] };
  
  DecomposeName: PUBLIC PROC[ name: ROPE ] RETURNS[ segment, domain, entity: ROPE ] =
     BEGIN
     segNameLength: INT = Rope.Find[ name, Sep ];
     domainNameLength: INT = Rope.Find[ name, Sep, segNameLength+1 ] - segNameLength - 1;
     segment_ Rope.Substr[ name, 0, segNameLength ];
     domain_ Rope.Substr[ name, segNameLength+1, domainNameLength ];
     entity_ Rope.Substr[ name, segNameLength+domainNameLength+2 ];
     END;

END. . .