Fossil

*******************************************************************************
**
** This file contains code to compute a revision history graph.
*/
#include "config.h"
#include "graph.h"
#include <assert.h>

/* Notes:
**
** The graph is laid out in 1 or more "rails".  A "rail" is a vertical
** band in the graph in which one can place nodes or arrows connecting
** nodes.  There can be between 1 and GR_MAX_RAIL rails.  If the graph
** is to complex to be displayed in GR_MAX_RAIL rails, it is omitted.
**
** A "riser" is the thick line that comes out of the top of a node and
** goes up to the next node on the branch, or to the top of the screen.
** A "descender" is a thick line that comes out of the bottom of a node
** and proceeds down to the bottom of the page.
**
** Invoke graph_init() to create a new GraphContext object.  Then
** call graph_add_row() to add nodes, one by one, to the graph.
** Nodes must be added in display order, from top to bottom.
** Then invoke graph_render() to run the layout algorithm.  The
** layout algorithm computes which rails all of the nodes sit on, and
** the rails used for merge arrows.
*/

#if INTERFACE

#define GR_MAX_RAIL   40      /* Max number of "rails" to display */

/* The graph appears vertically beside a timeline.  Each row in the
** timeline corresponds to a row in the graph.  GraphRow.idx is 0 for
** the top-most row and increases moving down.  Hence (in the absence of
** time skew) parents have a larger index than their children.
**
** The nParent field is -1 for entires that do not participate in the graph
** but which are included just so that we can capture their background color.
*/
struct GraphRow {
  int rid;                    /* The rid for the check-in */
  i8 nParent;                 /* Number of parents. */
  i8 nCherrypick;             /* Subset of aParent that are cherrypicks */
  i8 nNonCherrypick;          /* Number of non-cherrypick parents */
  int *aParent;               /* Array of parents.  0 element is primary .*/
  char *zBranch;              /* Branch name */
  char *zBgClr;               /* Background Color */
  char zUuid[HNAME_MAX+1];    /* Check-in for file ID */

  GraphRow *pNext;            /* Next row down in the list of all rows */
  GraphRow *pPrev;            /* Previous row */

  int idx;                    /* Row index.  Top row is smallest. */
  int idxTop;                 /* Direct descendent highest up on the graph */
  GraphRow *pChild;           /* Child immediately above this node */
  u8 isDup;                   /* True if this is duplicate of a prior entry */
  u8 isLeaf;                  /* True if this is a leaf node */
  u8 isStepParent;            /* pChild is actually a step-child */
  u8 hasNormalOutMerge;       /* Is parent of at laest 1 non-cherrypick merge */
  u8 timeWarp;                /* Child is earlier in time */
  u8 bDescender;              /* True if riser from bottom of graph to here. */
  i8 iRail;                   /* Which rail this check-in appears on. 0-based.*/
  i8 mergeOut;                /* Merge out to this rail.  -1 if no merge-out */
  u8 mergeIn[GR_MAX_RAIL];    /* Merge in from non-zero rails */
  int aiRiser[GR_MAX_RAIL];   /* Risers from this node to a higher row. */
  int mergeUpto;              /* Draw the mergeOut rail up to this level */
  int cherrypickUpto;         /* Continue the mergeOut rail up to here */
  u64 mergeDown;              /* Draw merge lines up from bottom of graph */
  u64 cherrypickDown;         /* Draw cherrypick lines up from bottom */

  u64 railInUse;              /* Mask of occupied rails at this row */
};

/* Context while building a graph
*/
struct GraphContext {
  int nErr;                  /* Number of errors encountered */

  GraphRow **apHash;         /* Hash table of GraphRow objects.  Key: rid */
};

#endif

/* The N-th bit */
#define BIT(N)  (((u64)1)<<(N))

/*
** Number of rows before and answer a node with a riser or descender
** that goes off-screen before we can reuse that rail.
*/
#define RISER_MARGIN 4


/*
** Malloc for zeroed space.  Panic if unable to provide the
** requested space.
*/
void *safeMalloc(int nByte){
  void *p = fossil_malloc(nByte);

  int iBestDist = 9999;
  u64 inUseMask = 0;
  for(pRow=p->pFirst; pRow && pRow->idx<top; pRow=pRow->pNext){}
  while( pRow && pRow->idx<=btm ){
    inUseMask |= pRow->railInUse;
    pRow = pRow->pNext;
  }
  for(i=0; i<GR_MAX_RAIL; i++){
    if( (inUseMask & BIT(i))==0 ){
      int dist;
      if( iNearto<=0 ){
        return i;
      }
      dist = i - iNearto;
      if( dist<0 ) dist = -dist;

  if( iBest>p->mxRail ) p->mxRail = iBest;
  return iBest;
}

/*
** Assign all children of node pBottom to the same rail as pBottom.
*/
static void assignChildrenToRail(GraphRow *pBottom, u32 tmFlags){
  int iRail = pBottom->iRail;
  GraphRow *pCurrent;
  GraphRow *pPrior;
  u64 mask = ((u64)1)<<iRail;

  pBottom->railInUse |= mask;
  pPrior = pBottom;
  for(pCurrent=pBottom->pChild; pCurrent; pCurrent=pCurrent->pChild){
    assert( pPrior->idx > pCurrent->idx );
    assert( pCurrent->iRail<0 );
    pCurrent->iRail = iRail;
    pCurrent->railInUse |= mask;
    pPrior->aiRiser[iRail] = pCurrent->idx;
    while( pPrior->idx > pCurrent->idx ){
      pPrior->railInUse |= mask;
      pPrior = pPrior->pPrev;
      assert( pPrior!=0 );
    }
  }
  /* Mask of additional rows for the riser to infinity */
  if( !pPrior->isLeaf && (tmFlags & TIMELINE_DISJOINT)==0 ){
    int n = RISER_MARGIN;
    GraphRow *p;
    for(p=pPrior; p && (n--)>0; p=p->pPrev){
      p->railInUse |= mask;
    }
  }
}

/*
** Create a merge-arrow riser going from pParent up to pChild.
*/
static void createMergeRiser(
  GraphContext *p,
  GraphRow *pParent,
  GraphRow *pChild,
  int isCherrypick
){
  int u;
  u64 mask;
  GraphRow *pLoop;

  if( pParent->mergeOut<0 ){
    u = pParent->aiRiser[pParent->iRail];
    if( u>0 && u<pChild->idx ){
      /* The thick arrow up to the next primary child of pDesc goes
      ** further up than the thin merge arrow riser, so draw them both
      ** on the same rail. */
      pParent->mergeOut = pParent->iRail;
    }else{
      /* The thin merge arrow riser is taller than the thick primary
      ** child riser, so use separate rails. */
      int iTarget = pParent->iRail;
      int iBtm = pParent->idx - (u==0 ? RISER_MARGIN : 1);
      pParent->mergeOut = findFreeRail(p, pChild->idx, iBtm, iTarget);
      mask = BIT(pParent->mergeOut);
      for(pLoop=pChild->pNext; pLoop && pLoop->rid!=pParent->rid;
           pLoop=pLoop->pNext){
        pLoop->railInUse |= mask;
      }
    }
  }

    ){
      p->mxRail++;
    }
  }
}

/*
** Draw a riser from pRow upward to indicate that it is going
** to a node that is off the graph to the top.
*/
static void riser_to_top(GraphRow *pRow){
  u64 mask = BIT(pRow->iRail);
  int n = RISER_MARGIN;
  pRow->aiRiser[pRow->iRail] = 0;
  while( pRow && (n--)>0 ){
    pRow->railInUse |= mask;
    pRow = pRow->pPrev;
  }
}


/*

    if( pRow->idxTop < pParent->idxTop ){
      pParent->pChild = pRow;
      pParent->idxTop = pRow->idxTop;
    }
  }

  if( tmFlags & TIMELINE_FILLGAPS ){
    /* If a node has no pChild but there is a node higher up in the graph
    ** that is in the same branch and that other node has no parent in
    ** the graph, the lower node a step-child of the upper node.  This will
    ** be represented on the graph by a thick dotted line without an arrowhead.
    */
    for(pRow=p->pFirst; pRow; pRow=pRow->pNext){
      if( pRow->pChild ) continue;
      for(pLoop=pRow->pPrev; pLoop; pLoop=pLoop->pPrev){
        if( pLoop->nParent>0
         && pLoop->zBranch==pRow->zBranch
         && hashFind(p,pLoop->aParent[0])==0
        ){
          pRow->pChild = pLoop;
          pRow->idxTop = pLoop->idxTop;
          pRow->isStepParent = 1;
          pLoop->aParent[0] = pRow->rid;
          break;
        }
      }
    }
  }

  /* Identify rows where the primary parent is off screen.  Assign
  ** each to a rail and draw descenders downward.
  **
  ** Strive to put the "trunk" branch on far left.
  */
  zTrunk = persistBranchName(p, "trunk");
  for(i=0; i<2; i++){
    for(pRow=p->pLast; pRow; pRow=pRow->pPrev){
      if( pRow->isDup ) continue;
      if( pRow->nParent<0 ) continue;
      if( i==0 ){
        if( pRow->zBranch!=zTrunk ) continue;
      }else {
        if( pRow->iRail>=0 ) continue;
      }
      if( pRow->nParent==0 || hashFind(p,pRow->aParent[0])==0 ){

        pRow->iRail = findFreeRail(p, pRow->idxTop, pRow->idx+RISER_MARGIN, 0);



        if( p->mxRail>=GR_MAX_RAIL ) return;
        mask = BIT(pRow->iRail);
        if( !omitDescenders ){
          int n = RISER_MARGIN;
          pRow->bDescender = pRow->nParent>0;
          for(pLoop=pRow; pLoop && (n--)>0; pLoop=pLoop->pNext){
            pLoop->railInUse |= mask;
          }
        }
        assignChildrenToRail(pRow, tmFlags);
      }
    }
  }

  /* Assign rails to all rows that are still unassigned.
  */
  for(pRow=p->pLast; pRow; pRow=pRow->pPrev){

          pLoop->railInUse |= mask;
        }
      }
    }
    mask = BIT(pRow->iRail);
    pRow->railInUse |= mask;
    if( pRow->pChild ){
      assignChildrenToRail(pRow, tmFlags);
    }else if( !omitDescenders && count_nonbranch_children(pRow->rid)!=0 ){
      if( !pRow->timeWarp ) riser_to_top(pRow);
    }
    if( pParent ){
      for(pLoop=pParent->pPrev; pLoop && pLoop!=pRow; pLoop=pLoop->pPrev){
        pLoop->railInUse |= mask;
      }

    var y0 = from.y + node.h/2;
    var y1 = Math.ceil(to.y + node.h + arw.h/2);
    drawLine(line,color,x,y0,null,y1);
    x = to.x + (node.w-arw.w)/2;
    var n = drawBox(arw.cls,null,x,y);
    if(color) n.style.borderBottomColor = color;
  }
  function drawDotted(from,to,color){
    var x = to.x + (node.w-line.w)/2;
    var y0 = from.y + node.h/2;
    var y1 = Math.ceil(to.y + node.h);
    drawLine(dotLine,color,x,y0,null,y1);
  }
  /* Draw thin horizontal or vertical lines representing merges */
  function drawMergeLine(x0,y0,x1,y1){

      var e = document.getElementById("mc"+p.id);
      if(e) e.style.backgroundColor = p.bg;
      e = document.getElementById("md"+p.id);
      if(e) e.style.backgroundColor = p.bg;
    }
    if( p.r<0 ) return;
    if( p.u>0 ) drawUpArrow(p,tx.rowinfo[p.u-tx.iTopRow],p.fg);
    if( p.sb>0 ) drawDotted(p,tx.rowinfo[p.sb-tx.iTopRow],null);
    var cls = node.cls;
    if( p.hasOwnProperty('mi') && p.mi.length ) cls += " merge";
    if( p.f&1 ) cls += " leaf";
    var n = drawBox(cls,p.bg,p.x,p.y);
    n.id = "tln"+p.id;
    n.onclick = clickOnNode;
    n.style.zIndex = 10;
    if( !tx.omitDescenders ){
      if( p.u==0 ){
        if( p.hasOwnProperty('mo') && p.r==p.mo ){
          var top = tx.rowinfo[p.mu-tx.iTopRow]
          drawUpArrow(p,{x: p.x, y: top.y-node.h}, p.fg);
        }else if( p.y>100 ){
          drawUpArrow(p,{x: p.x, y: p.y-50}, p.fg);
        }else{
          drawUpArrow(p,{x: p.x, y: 0},p.fg);
        }
      }
      if( p.hasOwnProperty('d') ){
        if( p.y + 150 >= btm ){
          drawUpArrow({x: p.x, y: btm - node.h/2},p,p.fg);
        }else{
          drawUpArrow({x: p.x, y: p.y+50},p,p.fg);
          drawDotted({x: p.x, y: p.y+63},{x: p.x, y: p.y+50-node.h/2},null);
        }
      }
    }
    if( p.hasOwnProperty('mo') ){
      var x0 = p.x + node.w/2;
      var x1 = p.mo*railPitch + node.w/2;
      var u = tx.rowinfo[p.mu-tx.iTopRow];
      var y1 = miLineY(u);
      if( p.u<0 || p.mo!=p.r ){