--  DirectoryInternal.mesa (last edited by: Keith on: October 8, 1980  11:06 PM)

DIRECTORY
  Directory USING [maxDirectoryNameLength, maxPathNameLength],
  Environment USING [wordsPerPage],
  File USING [Capability, nullCapability],
  Space USING [Handle, PageCount];

DirectoryInternal: DEFINITIONS =
-- this interface defines the global data types used by the directory system

BEGIN

  --  Monitor/Module Control

  DirectoryLock: MONITORLOCK;
  swapUnitSize: Space.PageCount = 1;  --  size of uniform swap units assigned by directory
  
  -- Directory B-Tree definitions
  
  DirectoryPageHandle: TYPE = LONG BASE POINTER TO DirectoryPage;
  PagePointer: TYPE = DirectoryPageHandle RELATIVE POINTER [0..65535] TO
    DirectoryPage;
  nilPagePointer: PagePointer = LAST[PagePointer];

  DirectoryEntryHandle: TYPE = LONG POINTER TO DirectoryEntry;
  
  DirectoryEntry: TYPE = MACHINE DEPENDENT RECORD [
    cap: File.Capability,
    pointer: PagePointer,
    name: StringBody _ [length: 0, maxlength: Directory.maxDirectoryNameLength, text:]];
  
  DirectoryPage: TYPE = MACHINE DEPENDENT RECORD [
    size(0:0..8): [0.. 256], -- number of words used in this page
    free(0:9.. 9): BOOLEAN,  -- TRUE if page is not in use
    filler(0: 10.. 15): [0.. 64),  --  used for B-Tree validation
    top(1:0..15): PagePointer,  -- if this is the first page, this field points to the root 
    parent(2:0..15): PagePointer, -- the parent of this page
    lastPointer(3:0..15): PagePointer, -- the last pointer in this page
    entries(emptySize:0..(Environment.wordsPerPage-emptySize)*16 - 1):
      ARRAY [0..Environment.wordsPerPage-emptySize) OF UNSPECIFIED -- the entries
    ];
  
  emptySize: CARDINAL = 4; -- the size of an empty page
  overhead: CARDINAL = SIZE[File.Capability] + SIZE[PagePointer];
  
  DirectoryDescriptor: TYPE = RECORD [
    base: DirectoryPageHandle _ NIL,
    top: PagePointer _ nilPagePointer,
    size: CARDINAL, -- in pages
    space: Space.Handle];
  
  -- Directory Tree Definitions
  -- The directory tree (or D-Tree) is a multiway tree which is used to store the subdirectory structure of
  -- a volume.  This way, we don't have to open up a bunch of directories in order to translate a path
  -- name.  The format of the tree is:
  --  Node 0 (top): level -1.  Son pointer points to RootDir, bro pointer to free node list.  Capability
  --    is capability of the directory tree file (with full permissions).  Name is empty.
  --  Node 1, level 0.  RootDir.  Bro pointer points to self, son pointer to first son.
  -- Subsequent nodes.  Son pointer points to first son, bro to sibling.  If no son, son pointer points to self.
  --    If no sibling, bro pointer points to parent.
  
  PDT: TYPE = LONG BASE POINTER TO DTNode;
  PDTNode: TYPE = PDT RELATIVE POINTER [0.. 65535] TO DTNode;
  pDTnil: PDTNode = LAST[PDTNode];
  
  DTNode: TYPE = RECORD [
      name: StringBody _ [length: 0, maxlength: Directory.maxDirectoryNameLength, text: ],
      array: PACKED ARRAY [0.. Directory.maxDirectoryNameLength) OF CHARACTER _ ALL [' ],
      cap: File.Capability _ File.nullCapability,
      son: PDTNode _ pDTnil,
      bro: PDTNode _ pDTnil,
      level: CARDINAL _ 0];
  
  -- Directory Contexts Definitions
  
  Context: TYPE = RECORD [
      wdName: StringBody _ [length: 0, maxlength: Directory.maxPathNameLength, text:],
      array: PACKED ARRAY [0.. Directory.maxPathNameLength) OF CHARACTER _ ALL [' ],
      pDC: CARDINAL _ 0,
      valid: BOOLEAN _ FALSE,
      pSP: LONG POINTER TO SPRecord _ NIL];
  
  SPRecord: TYPE = RECORD [
      spName: StringBody _ [length: 0, maxlength: Directory.maxPathNameLength, text:],
      array: PACKED ARRAY [0.. Directory.maxPathNameLength) OF CHARACTER _ ALL[' ],
      pSP: LONG POINTER TO SPRecord _ NIL,
      pDC: CARDINAL _ 0,  -- the SP element directory
      defined: BOOLEAN _ FALSE,
      v: SELECT type: * FROM
          noWD => NULL,
          withWD => [
              cap: File.Capability _ File.nullCapability,  -- what we think the WD cap is
              pWD: LONG POINTER TO Context  -- the qualifying working Directory-- ],
              ENDCASE
      ];

  -- Directory Leader Page Constants and others
  
  leaderPageSize: CARDINAL = 1;
  leaderPageOffset: CARDINAL = 64;  --  word in leader page at which the Directory Prop List starts
  initDirSize: Space.PageCount = 16; -- initial size of a directory
  initDTSize: Space.PageCount = 16; -- initial size of a directory tree file
  directoryIncrement: CARDINAL = 10;  --  number of pages the directories and D-Trees will grow
  maxDirSize: CARDINAL = 256 - leaderPageSize;  --  number of data pages in directory/D-Tree
  --  note that the module DirectoryTreesImpl makes the assumption  that
  --  maxDirSize = n * directoryIncrement + initDirSize (or initDTSize) for some integer n.
  
  END.


LOG

Time: August 21, 1980  10:52 AM By: Keith	Action:  Created File(1792)\4b17B6i53I226i73I15bi22BI72i50I9bi28BI559i33I28i5I4i22I38i28I36i56I39i23I43i29I142i11I41i25I207i9I35bi26BI5i299I7i134I7i18I10i219I498bi30BI6b7B907bi31BI1bi10BI70i65I41i27I40i38I36i59I47i211I13i
Time: October 6, 1980  5:34 PM By: Keith	Action:  Changed WD length in Context to maxPathNameLength.  Added documentation (!).\i71b7B