guix-kreyren/guix/graph.scm
Ludovic Courtès 16155bbeb8
graph: Don't insist on "Helvetica" in the Graphviz backend.
Suggested by Fulbert <fulbert@bluewin.ch>.

* guix/graph.scm (emit-node): Use "sans" instead of "Helvetica".
2020-10-22 17:10:21 +02:00

376 lines
13 KiB
Scheme
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2015, 2016, 2020 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016 Ricardo Wurmus <rekado@elephly.net>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix graph)
#:use-module (guix store)
#:use-module (guix monads)
#:use-module (guix records)
#:use-module (guix sets)
#:use-module (rnrs io ports)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-26)
#:use-module (ice-9 match)
#:use-module (ice-9 vlist)
#:export (node-type
node-type?
node-type-identifier
node-type-label
node-type-edges
node-type-convert
node-type-name
node-type-description
node-edges
node-back-edges
traverse/depth-first
node-transitive-edges
node-reachable-count
shortest-path
%graph-backends
%d3js-backend
%graphviz-backend
graph-backend?
graph-backend
graph-backend-name
graph-backend-description
export-graph))
;;; Commentary:
;;;
;;; This module provides an abstract way to represent graphs and to manipulate
;;; them. It comes with several such representations for packages,
;;; derivations, and store items. It also provides a generic interface for
;;; exporting graphs in an external format, including a Graphviz
;;; implementation thereof.
;;;
;;; Code:
;;;
;;; Node types.
;;;
(define-record-type* <node-type> node-type make-node-type
node-type?
(identifier node-type-identifier) ;node -> M identifier
(label node-type-label) ;node -> string
(edges node-type-edges) ;node -> M list of nodes
(convert node-type-convert ;any -> M list of nodes
(default (lift1 list %store-monad)))
(name node-type-name) ;string
(description node-type-description)) ;string
(define (%node-edges type nodes cons-edge)
(with-monad %store-monad
(match type
(($ <node-type> identifier label node-edges)
(define (add-edge node edges)
(>>= (node-edges node)
(lambda (nodes)
(return (fold (cut cons-edge node <> <>)
edges nodes)))))
(mlet %store-monad ((edges (foldm %store-monad
add-edge vlist-null nodes)))
(return (lambda (node)
(reverse (vhash-foldq* cons '() node edges)))))))))
(define (node-edges type nodes)
"Return, as a monadic value, a one-argument procedure that, given a node of TYPE,
returns its edges. NODES is taken to be the sinks of the global graph."
(%node-edges type nodes
(lambda (source target edges)
(vhash-consq source target edges))))
(define (node-back-edges type nodes)
"Return, as a monadic value, a one-argument procedure that, given a node of TYPE,
returns its back edges. NODES is taken to be the sinks of the global graph."
(%node-edges type nodes
(lambda (source target edges)
(vhash-consq target source edges))))
(define (traverse/depth-first proc seed nodes node-edges)
"Do a depth-first traversal of NODES along NODE-EDGES, calling PROC with
each node and the current result, and visiting each reachable node exactly
once. NODES must be a list of nodes, and NODE-EDGES must be a one-argument
procedure as returned by 'node-edges' or 'node-back-edges'."
(let loop ((nodes (append-map node-edges nodes))
(result seed)
(visited (setq)))
(match nodes
(()
result)
((head . tail)
(if (set-contains? visited head)
(loop tail result visited)
(let ((edges (node-edges head)))
(loop (append edges tail)
(proc head result)
(set-insert head visited))))))))
(define (node-transitive-edges nodes node-edges)
"Return the list of nodes directly or indirectly connected to NODES
according to the NODE-EDGES procedure. NODE-EDGES must be a one-argument
procedure that, given a node, returns its list of direct dependents; it is
typically returned by 'node-edges' or 'node-back-edges'."
(traverse/depth-first cons '() nodes node-edges))
(define (node-reachable-count nodes node-edges)
"Return the number of nodes reachable from NODES along NODE-EDGES."
(traverse/depth-first (lambda (_ count)
(+ 1 count))
0
nodes node-edges))
(define (shortest-path node1 node2 type)
"Return as a monadic value the shortest path, represented as a list, from
NODE1 to NODE2 of the given TYPE. Return #f when there is no path."
(define node-edges
(node-type-edges type))
(define (find-shortest lst)
;; Return the shortest path among LST, where each path is represented as a
;; vlist.
(let loop ((lst lst)
(best +inf.0)
(shortest #f))
(match lst
(()
shortest)
((head . tail)
(let ((len (vlist-length head)))
(if (< len best)
(loop tail len head)
(loop tail best shortest)))))))
(define (find-path node path paths)
;; Return the a vhash that maps nodes to paths, with each path from the
;; given node to NODE2.
(define (augment-paths child paths)
;; When using %REFERENCE-NODE-TYPE, nodes can contain self references,
;; hence this test.
(if (eq? child node)
(store-return paths)
(find-path child vlist-null paths)))
(cond ((eq? node node2)
(store-return (vhash-consq node (vlist-cons node path)
paths)))
((vhash-assq node paths)
(store-return paths))
(else
;; XXX: We could stop recursing if one if CHILDREN is NODE2, but in
;; practice it's good enough.
(mlet* %store-monad ((children (node-edges node))
(paths (foldm %store-monad
augment-paths
paths
children)))
(define sub-paths
(filter-map (lambda (child)
(match (vhash-assq child paths)
(#f #f)
((_ . path) path)))
children))
(match sub-paths
(()
(return (vhash-consq node #f paths)))
(lst
(return (vhash-consq node
(vlist-cons node (find-shortest sub-paths))
paths))))))))
(mlet %store-monad ((paths (find-path node1
(vlist-cons node1 vlist-null)
vlist-null)))
(return (match (vhash-assq node1 paths)
((_ . #f) #f)
((_ . path) (vlist->list path))))))
;;;
;;; Graphviz export.
;;;
(define-record-type <graph-backend>
(graph-backend name description prologue epilogue node edge)
graph-backend?
(name graph-backend-name)
(description graph-backend-description)
(prologue graph-backend-prologue)
(epilogue graph-backend-epilogue)
(node graph-backend-node)
(edge graph-backend-edge))
(define %colors
;; See colortbl.h in Graphviz.
#("red" "magenta" "blue" "cyan3" "darkseagreen"
"peachpuff4" "darkviolet" "dimgrey" "darkgoldenrod"))
(define (pop-color hint)
"Return a Graphviz color based on HINT, an arbitrary object."
(let ((index (hash hint (vector-length %colors))))
(vector-ref %colors index)))
(define (emit-prologue name port)
(format port "digraph \"Guix ~a\" {\n"
name))
(define (emit-epilogue port)
(display "\n}\n" port))
(define (emit-node id label port)
(format port " \"~a\" [label = \"~a\", shape = box, fontname = sans];~%"
id label))
(define (emit-edge id1 id2 port)
(format port " \"~a\" -> \"~a\" [color = ~a];~%"
id1 id2 (pop-color id1)))
(define %graphviz-backend
(graph-backend "graphviz"
"Generate graph in DOT format for use with Graphviz."
emit-prologue emit-epilogue
emit-node emit-edge))
;;;
;;; d3js export.
;;;
(define (emit-d3js-prologue name port)
(format port "\
<!DOCTYPE html>
<html>
<head>
<meta charset=\"utf-8\">
<style>
text {
font: 10px sans-serif;
pointer-events: none;
}
</style>
<script type=\"text/javascript\" src=\"~a\"></script>
</head>
<body>
<script type=\"text/javascript\">
var nodes = {},
nodeArray = [],
links = [];
" (search-path %load-path "d3.v3.js")))
(define (emit-d3js-epilogue port)
(format port "</script><script type=\"text/javascript\" src=\"~a\"></script></body></html>"
(search-path %load-path "graph.js")))
(define (emit-d3js-node id label port)
(format port "\
nodes[\"~a\"] = {\"id\": \"~a\", \"label\": \"~a\", \"index\": nodeArray.length};
nodeArray.push(nodes[\"~a\"]);~%"
id id label id))
(define (emit-d3js-edge id1 id2 port)
(format port "links.push({\"source\": \"~a\", \"target\": \"~a\"});~%"
id1 id2))
(define %d3js-backend
(graph-backend "d3js"
"Generate chord diagrams with d3js."
emit-d3js-prologue emit-d3js-epilogue
emit-d3js-node emit-d3js-edge))
;;;
;;; Cypher export.
;;;
(define (emit-cypher-prologue name port)
(format port ""))
(define (emit-cypher-epilogue port)
(format port ""))
(define (emit-cypher-node id label port)
(format port "MERGE (p:Package { id: ~s }) SET p.name = ~s;~%"
id label ))
(define (emit-cypher-edge id1 id2 port)
(format port "MERGE (a:Package { id: ~s });~%" id1)
(format port "MERGE (b:Package { id: ~s });~%" id2)
(format port "MATCH (a:Package { id: ~s }), (b:Package { id: ~s }) CREATE UNIQUE (a)-[:NEEDS]->(b);~%"
id1 id2))
(define %cypher-backend
(graph-backend "cypher"
"Generate Cypher queries."
emit-cypher-prologue emit-cypher-epilogue
emit-cypher-node emit-cypher-edge))
;;;
;;; Shared.
;;;
(define %graph-backends
(list %graphviz-backend
%d3js-backend
%cypher-backend))
(define* (export-graph sinks port
#:key
reverse-edges? node-type
(backend %graphviz-backend))
"Write to PORT the representation of the DAG with the given SINKS, using the
given BACKEND. Use NODE-TYPE to traverse the DAG. When REVERSE-EDGES? is
true, draw reverse arrows."
(match backend
(($ <graph-backend> _ _ emit-prologue emit-epilogue emit-node emit-edge)
(emit-prologue (node-type-name node-type) port)
(match node-type
(($ <node-type> node-identifier node-label node-edges)
(let loop ((nodes sinks)
(visited (set)))
(match nodes
(()
(with-monad %store-monad
(emit-epilogue port)
(store-return #t)))
((head . tail)
(mlet %store-monad ((id (node-identifier head)))
(if (set-contains? visited id)
(loop tail visited)
(mlet* %store-monad ((dependencies (node-edges head))
(ids (mapm %store-monad
node-identifier
dependencies)))
(emit-node id (node-label head) port)
(for-each (lambda (dependency dependency-id)
(if reverse-edges?
(emit-edge dependency-id id port)
(emit-edge id dependency-id port)))
dependencies ids)
(loop (append dependencies tail)
(set-insert id visited)))))))))))))
;;; graph.scm ends here