Method RenderGraphvizDot

db/revtree.go:662–762

Render the RevTree in Graphviz Dot format, which can then be used to generate a PNG diagram like http://cbmobile-bucket.s3.amazonaws.com/diagrams/example-sync-gateway-revtrees/three_branches.png using the command: dot -Tpng revtree.dot > revtree.png or an online tool such as webgraphviz.com

()

// like http://cbmobile-bucket.s3.amazonaws.com/diagrams/example-sync-gateway-revtrees/three_branches.png
// using the command: dot -Tpng revtree.dot > revtree.png or an online tool such as webgraphviz.com
func (tree RevTree) RenderGraphvizDot() string {

	resultBuffer := bytes.Buffer{}

	// Helper func to surround graph node w/ double quotes
	surroundWithDoubleQuotes := func(orig string) string {
		return fmt.Sprintf(`"%s"`, orig)
	}

	// Helper func to get the graphviz dot representation of a node
	dotRepresentation := func(node *RevInfo) string {
		switch node.Deleted {
		case false:
			return fmt.Sprintf(
				"%s -> %s; ",
				surroundWithDoubleQuotes(node.Parent),
				surroundWithDoubleQuotes(node.ID),
			)
		default:
			multilineResult := bytes.Buffer{}
			multilineResult.WriteString(
				fmt.Sprintf(
					`%s [fontcolor=red];`,
					surroundWithDoubleQuotes(node.ID),
				),
			)
			multilineResult.WriteString(
				fmt.Sprintf(
					`%s -> %s [label="Tombstone", fontcolor=red];`,
					surroundWithDoubleQuotes(node.Parent),
					surroundWithDoubleQuotes(node.ID),
				),
			)

			return multilineResult.String()
		}

	}

	// Helper func to append node to result: parent -> child;
	dupes := base.Set{}
	appendNodeToResult := func(node *RevInfo) {
		nodeAsDotText := dotRepresentation(node)
		if dupes.Contains(nodeAsDotText) {
			return
		} else {
			dupes[nodeAsDotText] = struct{}{}
		}
		resultBuffer.WriteString(nodeAsDotText)
	}

	// Start graphviz dot file
	resultBuffer.WriteString("digraph graphname{")

	// This function will be called back for every leaf node in tree
	leafProcessor := func(leaf *RevInfo) {

		// Append the leaf to the output