.

wcfs/internal/xbtree.py

@@ -78,7 +78,7 @@ in left-to-right order.
 from __future__ import print_function, absolute_import
 
 from BTrees import check as bcheck
-from golang import panic
+from golang import func, panic
 from golang.gcompat import qq
 import itertools
 import re
@@ -198,6 +198,19 @@ def TopoEncode(tree):
     topo = ''
 
     # breadth-first traversal of the tree with '/' injected in between layers
+    for nodev in _walkBFS(tree):
+        if len(topo) != 0:
+            topo += '/'
+        tnodev = []
+        for node in nodev:
+            assert isinstance(node, (Tree, Bucket))
+            tnode = ('T' if isinstance(node, Tree) else 'B') + \
+                        (','.join(['%d' % _ for _ in node.keyv]))
+            tnodev.append(tnode)
+        topo += '-'.join(tnodev)
+
+
+    """
     queue  = [tree, '/']
     while 1:
         x = queue.pop(0)
@@ -218,6 +231,7 @@ def TopoEncode(tree):
 
         if isinstance(node, Tree):
             queue += node.children
+    """
 
     if 1: # make sure that every topology we emit, can be loaded back
         t2 = TopoDecode(topo)
@@ -226,6 +240,23 @@ def TopoEncode(tree):
     return topo
 
 
+# _walkBFS walks tree in breadth-first order layer by layer.
+def _walkBFS(tree): # i[] of [](of nodes on each level)
+    assert isinstance(tree, Tree)
+    currentv = []
+    nextq    = [tree]
+    while len(nextq) > 0:
+        yield tuple(nextq)
+        currentq = nextq
+        nextq    = []
+        while len(currentq) > 0:
+            node = currentq.pop(0)
+            assert isinstance(node, (Tree, Bucket))
+            if isinstance(node, Tree):
+                nextq += node.children
+
+
+
 # TopoDecode decodes topology-encoded text into Tree structure.
 #
 # See top-level docstring for description of topology encoding.
@@ -392,3 +423,87 @@ def _assertIncv(v):
         if not (v[i] > prev):
             panic("assert incv: [%d] not ↑: %s -> %s" % (i, v[i], prev))
         prev = v[i]
+
+
+
+
+
+# ----------------------------------------
+
+import sys
+
+# graphviz returns tree graph representation in dot language.
+@func(Tree)
+def graphviz(t):
+    assert isinstance(t, Tree)
+
+    symtab = {} # node -> name
+
+    outv = []
+    def emit(line):
+        outv.append(line)
+
+    emit('digraph {')
+    emit('  splines=false')
+
+    for (level, nodev) in enumerate(_walkBFS(t)):
+        for (i, node) in enumerate(nodev):
+            assert isinstance(node, (Tree,Bucket))
+
+            # register node insymtab
+            assert node not in symtab
+            kind = ('T' if isinstance(node, Tree) else 'B')
+            symtab[node] = '%s%d:%d' % (kind, level, i)
+
+            # emit node itself
+            # approach based on https://github.com/Felerius/btree-generator
+            emit('  %s' % qq(symtab[node]))
+            emit('  [')
+            emit('    shape = none')
+            emit('    label = <<table border="1" cellborder="0" cellspacing="0">')
+            emit('                <tr>')
+            for (j,key) in enumerate(node.keyv):
+                if kind == 'T':
+                    emit('                  <td port="con%d"></td>' % j)
+                if 1:
+                    emit('                  <td port="key%d">%d</td>' % (j,key))
+            emit('                  <td port="con%d"></td>' % len(node.keyv))
+
+            emit('                </tr>')
+            emit('             </table>>')
+            emit('  ]')
+
+    # second pass: emit links + node ranks
+    for nodev in _walkBFS(t):
+        # same rank for nodes on the same level
+        emit('')
+        emit('  {rank=same; %s}' % ' '.join([qq(symtab[_]) for _ in nodev]))
+        # links
+        for node in nodev:
+            if not isinstance(node, Tree):
+                continue
+            for (j,child) in enumerate(node.children):
+                emit('%s:"con%d" -> %s' % (qq(symtab[node]), j, qq(symtab[child])))
+
+    emit('}')
+    emit('')
+    return '\n'.join(outv)
+
+
+# topoview display topologies provided in argv.
+def topoview(argv):
+    if len(argv) == 0:
+        raise RuntimeError('E: empty argument')
+
+    topov = [TopoDecode(_) for _ in argv]
+
+    import graphviz as gv
+    #g = gv.Digraph(comment='AAA')
+    #print(g.render(format='pdf', view=True))
+    g = gv.Source(topov[0].graphviz())
+    print(g.source)
+    g.view()
+
+
+if __name__ == '__main__':
+    topoview(sys.argv[1:])