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c1a9b12d 1// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
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2// file at the top-level directory of this distribution and at
3// http://rust-lang.org/COPYRIGHT.
4//
5// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8// option. This file may not be copied, modified, or distributed
9// except according to those terms.
10
11//! Generate files suitable for use with [Graphviz](http://www.graphviz.org/)
12//!
13//! The `render` function generates output (e.g. an `output.dot` file) for
14//! use with [Graphviz](http://www.graphviz.org/) by walking a labelled
15//! graph. (Graphviz can then automatically lay out the nodes and edges
16//! of the graph, and also optionally render the graph as an image or
17//! other [output formats](
18//! http://www.graphviz.org/content/output-formats), such as SVG.)
19//!
20//! Rather than impose some particular graph data structure on clients,
21//! this library exposes two traits that clients can implement on their
22//! own structs before handing them over to the rendering function.
23//!
24//! Note: This library does not yet provide access to the full
25//! expressiveness of the [DOT language](
26//! http://www.graphviz.org/doc/info/lang.html). For example, there are
27//! many [attributes](http://www.graphviz.org/content/attrs) related to
28//! providing layout hints (e.g. left-to-right versus top-down, which
29//! algorithm to use, etc). The current intention of this library is to
30//! emit a human-readable .dot file with very regular structure suitable
31//! for easy post-processing.
32//!
33//! # Examples
34//!
35//! The first example uses a very simple graph representation: a list of
36//! pairs of ints, representing the edges (the node set is implicit).
37//! Each node label is derived directly from the int representing the node,
38//! while the edge labels are all empty strings.
39//!
c34b1796 40//! This example also illustrates how to use `Cow<[T]>` to return
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41//! an owned vector or a borrowed slice as appropriate: we construct the
42//! node vector from scratch, but borrow the edge list (rather than
43//! constructing a copy of all the edges from scratch).
44//!
45//! The output from this example renders five nodes, with the first four
46//! forming a diamond-shaped acyclic graph and then pointing to the fifth
47//! which is cyclic.
48//!
49//! ```rust
9cc50fc6 50//! #![feature(rustc_private)]
c1a9b12d 51//!
9cc50fc6 52//! use graphviz::IntoCow;
c34b1796 53//! use std::io::Write;
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54//! use graphviz as dot;
55//!
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56//! type Nd = isize;
57//! type Ed = (isize,isize);
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58//! struct Edges(Vec<Ed>);
59//!
c34b1796 60//! pub fn render_to<W: Write>(output: &mut W) {
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61//! let edges = Edges(vec!((0,1), (0,2), (1,3), (2,3), (3,4), (4,4)));
62//! dot::render(&edges, output).unwrap()
63//! }
64//!
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65//! impl<'a> dot::Labeller<'a> for Edges {
66//! type Node = Nd;
67//! type Edge = Ed;
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68//! fn graph_id(&'a self) -> dot::Id<'a> { dot::Id::new("example1").unwrap() }
69//!
70//! fn node_id(&'a self, n: &Nd) -> dot::Id<'a> {
71//! dot::Id::new(format!("N{}", *n)).unwrap()
72//! }
73//! }
74//!
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75//! impl<'a> dot::GraphWalk<'a> for Edges {
76//! type Node = Nd;
77//! type Edge = Ed;
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78//! fn nodes(&self) -> dot::Nodes<'a,Nd> {
79//! // (assumes that |N| \approxeq |E|)
80//! let &Edges(ref v) = self;
81//! let mut nodes = Vec::with_capacity(v.len());
62682a34 82//! for &(s,t) in v {
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83//! nodes.push(s); nodes.push(t);
84//! }
85//! nodes.sort();
86//! nodes.dedup();
87//! nodes.into_cow()
88//! }
89//!
90//! fn edges(&'a self) -> dot::Edges<'a,Ed> {
91//! let &Edges(ref edges) = self;
c34b1796 92//! (&edges[..]).into_cow()
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93//! }
94//!
95//! fn source(&self, e: &Ed) -> Nd { let &(s,_) = e; s }
96//!
97//! fn target(&self, e: &Ed) -> Nd { let &(_,t) = e; t }
98//! }
99//!
100//! # pub fn main() { render_to(&mut Vec::new()) }
101//! ```
102//!
103//! ```no_run
c34b1796 104//! # pub fn render_to<W:std::io::Write>(output: &mut W) { unimplemented!() }
1a4d82fc 105//! pub fn main() {
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106//! use std::fs::File;
107//! let mut f = File::create("example1.dot").unwrap();
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108//! render_to(&mut f)
109//! }
110//! ```
111//!
112//! Output from first example (in `example1.dot`):
113//!
114//! ```ignore
115//! digraph example1 {
116//! N0[label="N0"];
117//! N1[label="N1"];
118//! N2[label="N2"];
119//! N3[label="N3"];
120//! N4[label="N4"];
121//! N0 -> N1[label=""];
122//! N0 -> N2[label=""];
123//! N1 -> N3[label=""];
124//! N2 -> N3[label=""];
125//! N3 -> N4[label=""];
126//! N4 -> N4[label=""];
127//! }
128//! ```
129//!
130//! The second example illustrates using `node_label` and `edge_label` to
131//! add labels to the nodes and edges in the rendered graph. The graph
132//! here carries both `nodes` (the label text to use for rendering a
133//! particular node), and `edges` (again a list of `(source,target)`
134//! indices).
135//!
136//! This example also illustrates how to use a type (in this case the edge
137//! type) that shares substructure with the graph: the edge type here is a
138//! direct reference to the `(source,target)` pair stored in the graph's
139//! internal vector (rather than passing around a copy of the pair
140//! itself). Note that this implies that `fn edges(&'a self)` must
c34b1796 141//! construct a fresh `Vec<&'a (usize,usize)>` from the `Vec<(usize,usize)>`
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142//! edges stored in `self`.
143//!
144//! Since both the set of nodes and the set of edges are always
145//! constructed from scratch via iterators, we use the `collect()` method
146//! from the `Iterator` trait to collect the nodes and edges into freshly
147//! constructed growable `Vec` values (rather use the `into_cow`
148//! from the `IntoCow` trait as was used in the first example
149//! above).
150//!
151//! The output from this example renders four nodes that make up the
152//! Hasse-diagram for the subsets of the set `{x, y}`. Each edge is
153//! labelled with the &sube; character (specified using the HTML character
154//! entity `&sube`).
155//!
156//! ```rust
92a42be0 157//! #![feature(rustc_private)]
c1a9b12d 158//!
c34b1796 159//! use std::io::Write;
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160//! use graphviz as dot;
161//!
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162//! type Nd = usize;
163//! type Ed<'a> = &'a (usize, usize);
164//! struct Graph { nodes: Vec<&'static str>, edges: Vec<(usize,usize)> }
1a4d82fc 165//!
c34b1796 166//! pub fn render_to<W: Write>(output: &mut W) {
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167//! let nodes = vec!("{x,y}","{x}","{y}","{}");
168//! let edges = vec!((0,1), (0,2), (1,3), (2,3));
169//! let graph = Graph { nodes: nodes, edges: edges };
170//!
171//! dot::render(&graph, output).unwrap()
172//! }
173//!
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174//! impl<'a> dot::Labeller<'a> for Graph {
175//! type Node = Nd;
176//! type Edge = Ed<'a>;
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177//! fn graph_id(&'a self) -> dot::Id<'a> { dot::Id::new("example2").unwrap() }
178//! fn node_id(&'a self, n: &Nd) -> dot::Id<'a> {
179//! dot::Id::new(format!("N{}", n)).unwrap()
180//! }
181//! fn node_label<'b>(&'b self, n: &Nd) -> dot::LabelText<'b> {
92a42be0 182//! dot::LabelText::LabelStr(self.nodes[*n].into())
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183//! }
184//! fn edge_label<'b>(&'b self, _: &Ed) -> dot::LabelText<'b> {
92a42be0 185//! dot::LabelText::LabelStr("&sube;".into())
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186//! }
187//! }
188//!
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189//! impl<'a> dot::GraphWalk<'a> for Graph {
190//! type Node = Nd;
191//! type Edge = Ed<'a>;
85aaf69f 192//! fn nodes(&self) -> dot::Nodes<'a,Nd> { (0..self.nodes.len()).collect() }
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193//! fn edges(&'a self) -> dot::Edges<'a,Ed<'a>> { self.edges.iter().collect() }
194//! fn source(&self, e: &Ed) -> Nd { let & &(s,_) = e; s }
195//! fn target(&self, e: &Ed) -> Nd { let & &(_,t) = e; t }
196//! }
197//!
198//! # pub fn main() { render_to(&mut Vec::new()) }
199//! ```
200//!
201//! ```no_run
c34b1796 202//! # pub fn render_to<W:std::io::Write>(output: &mut W) { unimplemented!() }
1a4d82fc 203//! pub fn main() {
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204//! use std::fs::File;
205//! let mut f = File::create("example2.dot").unwrap();
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206//! render_to(&mut f)
207//! }
208//! ```
209//!
210//! The third example is similar to the second, except now each node and
211//! edge now carries a reference to the string label for each node as well
212//! as that node's index. (This is another illustration of how to share
213//! structure with the graph itself, and why one might want to do so.)
214//!
215//! The output from this example is the same as the second example: the
216//! Hasse-diagram for the subsets of the set `{x, y}`.
217//!
218//! ```rust
92a42be0 219//! #![feature(rustc_private)]
c1a9b12d 220//!
c34b1796 221//! use std::io::Write;
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222//! use graphviz as dot;
223//!
c34b1796 224//! type Nd<'a> = (usize, &'a str);
1a4d82fc 225//! type Ed<'a> = (Nd<'a>, Nd<'a>);
c34b1796 226//! struct Graph { nodes: Vec<&'static str>, edges: Vec<(usize,usize)> }
1a4d82fc 227//!
c34b1796 228//! pub fn render_to<W: Write>(output: &mut W) {
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229//! let nodes = vec!("{x,y}","{x}","{y}","{}");
230//! let edges = vec!((0,1), (0,2), (1,3), (2,3));
231//! let graph = Graph { nodes: nodes, edges: edges };
232//!
233//! dot::render(&graph, output).unwrap()
234//! }
235//!
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236//! impl<'a> dot::Labeller<'a> for Graph {
237//! type Node = Nd<'a>;
238//! type Edge = Ed<'a>;
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239//! fn graph_id(&'a self) -> dot::Id<'a> { dot::Id::new("example3").unwrap() }
240//! fn node_id(&'a self, n: &Nd<'a>) -> dot::Id<'a> {
241//! dot::Id::new(format!("N{}", n.0)).unwrap()
242//! }
243//! fn node_label<'b>(&'b self, n: &Nd<'b>) -> dot::LabelText<'b> {
244//! let &(i, _) = n;
92a42be0 245//! dot::LabelText::LabelStr(self.nodes[i].into())
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246//! }
247//! fn edge_label<'b>(&'b self, _: &Ed<'b>) -> dot::LabelText<'b> {
92a42be0 248//! dot::LabelText::LabelStr("&sube;".into())
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249//! }
250//! }
251//!
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252//! impl<'a> dot::GraphWalk<'a> for Graph {
253//! type Node = Nd<'a>;
254//! type Edge = Ed<'a>;
1a4d82fc 255//! fn nodes(&'a self) -> dot::Nodes<'a,Nd<'a>> {
c34b1796 256//! self.nodes.iter().map(|s| &s[..]).enumerate().collect()
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257//! }
258//! fn edges(&'a self) -> dot::Edges<'a,Ed<'a>> {
259//! self.edges.iter()
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260//! .map(|&(i,j)|((i, &self.nodes[i][..]),
261//! (j, &self.nodes[j][..])))
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262//! .collect()
263//! }
264//! fn source(&self, e: &Ed<'a>) -> Nd<'a> { let &(s,_) = e; s }
265//! fn target(&self, e: &Ed<'a>) -> Nd<'a> { let &(_,t) = e; t }
266//! }
267//!
268//! # pub fn main() { render_to(&mut Vec::new()) }
269//! ```
270//!
271//! ```no_run
c34b1796 272//! # pub fn render_to<W:std::io::Write>(output: &mut W) { unimplemented!() }
1a4d82fc 273//! pub fn main() {
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274//! use std::fs::File;
275//! let mut f = File::create("example3.dot").unwrap();
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276//! render_to(&mut f)
277//! }
278//! ```
279//!
280//! # References
281//!
282//! * [Graphviz](http://www.graphviz.org/)
283//!
284//! * [DOT language](http://www.graphviz.org/doc/info/lang.html)
285
286#![crate_name = "graphviz"]
e9174d1e 287#![unstable(feature = "rustc_private", issue = "27812")]
85aaf69f 288#![feature(staged_api)]
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289#![crate_type = "rlib"]
290#![crate_type = "dylib"]
e9174d1e 291#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
62682a34 292 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
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293 html_root_url = "https://doc.rust-lang.org/nightly/",
294 test(attr(allow(unused_variables), deny(warnings))))]
7453a54e 295#![cfg_attr(not(stage0), deny(warnings))]
62682a34 296
62682a34 297#![feature(str_escape)]
54a0048b 298#![feature(question_mark)]
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299
300use self::LabelText::*;
301
9cc50fc6 302use std::borrow::{Cow, ToOwned};
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303use std::io::prelude::*;
304use std::io;
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305
306/// The text for a graphviz label on a node or edge.
307pub enum LabelText<'a> {
308 /// This kind of label preserves the text directly as is.
309 ///
310 /// Occurrences of backslashes (`\`) are escaped, and thus appear
311 /// as backslashes in the rendered label.
85aaf69f 312 LabelStr(Cow<'a, str>),
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313
314 /// This kind of label uses the graphviz label escString type:
315 /// http://www.graphviz.org/content/attrs#kescString
316 ///
317 /// Occurrences of backslashes (`\`) are not escaped; instead they
318 /// are interpreted as initiating an escString escape sequence.
319 ///
320 /// Escape sequences of particular interest: in addition to `\n`
321 /// to break a line (centering the line preceding the `\n`), there
322 /// are also the escape sequences `\l` which left-justifies the
323 /// preceding line and `\r` which right-justifies it.
85aaf69f 324 EscStr(Cow<'a, str>),
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325
326 /// This uses a graphviz [HTML string label][html]. The string is
327 /// printed exactly as given, but between `<` and `>`. **No
328 /// escaping is performed.**
329 ///
330 /// [html]: http://www.graphviz.org/content/node-shapes#html
331 HtmlStr(Cow<'a, str>),
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332}
333
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334/// The style for a node or edge.
335/// See http://www.graphviz.org/doc/info/attrs.html#k:style for descriptions.
336/// Note that some of these are not valid for edges.
337#[derive(Copy, Clone, PartialEq, Eq, Debug)]
338pub enum Style {
339 None,
340 Solid,
341 Dashed,
342 Dotted,
343 Bold,
344 Rounded,
345 Diagonals,
346 Filled,
347 Striped,
348 Wedged,
349}
350
351impl Style {
352 pub fn as_slice(self) -> &'static str {
353 match self {
354 Style::None => "",
355 Style::Solid => "solid",
356 Style::Dashed => "dashed",
357 Style::Dotted => "dotted",
358 Style::Bold => "bold",
359 Style::Rounded => "rounded",
360 Style::Diagonals => "diagonals",
361 Style::Filled => "filled",
362 Style::Striped => "striped",
363 Style::Wedged => "wedged",
364 }
365 }
366}
367
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368// There is a tension in the design of the labelling API.
369//
370// For example, I considered making a `Labeller<T>` trait that
371// provides labels for `T`, and then making the graph type `G`
372// implement `Labeller<Node>` and `Labeller<Edge>`. However, this is
373// not possible without functional dependencies. (One could work
374// around that, but I did not explore that avenue heavily.)
375//
376// Another approach that I actually used for a while was to make a
377// `Label<Context>` trait that is implemented by the client-specific
378// Node and Edge types (as well as an implementation on Graph itself
379// for the overall name for the graph). The main disadvantage of this
380// second approach (compared to having the `G` type parameter
381// implement a Labelling service) that I have encountered is that it
382// makes it impossible to use types outside of the current crate
383// directly as Nodes/Edges; you need to wrap them in newtype'd
384// structs. See e.g. the `No` and `Ed` structs in the examples. (In
385// practice clients using a graph in some other crate would need to
386// provide some sort of adapter shim over the graph anyway to
387// interface with this library).
388//
389// Another approach would be to make a single `Labeller<N,E>` trait
390// that provides three methods (graph_label, node_label, edge_label),
391// and then make `G` implement `Labeller<N,E>`. At first this did not
392// appeal to me, since I had thought I would need separate methods on
393// each data variant for dot-internal identifiers versus user-visible
394// labels. However, the identifier/label distinction only arises for
395// nodes; graphs themselves only have identifiers, and edges only have
396// labels.
397//
398// So in the end I decided to use the third approach described above.
399
400/// `Id` is a Graphviz `ID`.
401pub struct Id<'a> {
85aaf69f 402 name: Cow<'a, str>,
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403}
404
405impl<'a> Id<'a> {
406 /// Creates an `Id` named `name`.
407 ///
408 /// The caller must ensure that the input conforms to an
409 /// identifier format: it must be a non-empty string made up of
410 /// alphanumeric or underscore characters, not beginning with a
411 /// digit (i.e. the regular expression `[a-zA-Z_][a-zA-Z_0-9]*`).
412 ///
413 /// (Note: this format is a strict subset of the `ID` format
414 /// defined by the DOT language. This function may change in the
415 /// future to accept a broader subset, or the entirety, of DOT's
416 /// `ID` format.)
417 ///
418 /// Passing an invalid string (containing spaces, brackets,
419 /// quotes, ...) will return an empty `Err` value.
85aaf69f 420 pub fn new<Name: IntoCow<'a, str>>(name: Name) -> Result<Id<'a>, ()> {
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421 let name = name.into_cow();
422 {
423 let mut chars = name.chars();
424 match chars.next() {
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425 Some(c) if is_letter_or_underscore(c) => {}
426 _ => return Err(()),
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427 }
428 if !chars.all(is_constituent) {
92a42be0 429 return Err(());
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430 }
431 }
92a42be0 432 return Ok(Id { name: name });
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433
434 fn is_letter_or_underscore(c: char) -> bool {
435 in_range('a', c, 'z') || in_range('A', c, 'Z') || c == '_'
436 }
437 fn is_constituent(c: char) -> bool {
438 is_letter_or_underscore(c) || in_range('0', c, '9')
439 }
440 fn in_range(low: char, c: char, high: char) -> bool {
c34b1796 441 low as usize <= c as usize && c as usize <= high as usize
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442 }
443 }
444
445 pub fn as_slice(&'a self) -> &'a str {
446 &*self.name
447 }
448
85aaf69f 449 pub fn name(self) -> Cow<'a, str> {
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450 self.name
451 }
452}
453
454/// Each instance of a type that implements `Label<C>` maps to a
455/// unique identifier with respect to `C`, which is used to identify
456/// it in the generated .dot file. They can also provide more
457/// elaborate (and non-unique) label text that is used in the graphviz
458/// rendered output.
459
460/// The graph instance is responsible for providing the DOT compatible
461/// identifiers for the nodes and (optionally) rendered labels for the nodes and
462/// edges, as well as an identifier for the graph itself.
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463pub trait Labeller<'a> {
464 type Node;
465 type Edge;
466
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467 /// Must return a DOT compatible identifier naming the graph.
468 fn graph_id(&'a self) -> Id<'a>;
469
470 /// Maps `n` to a unique identifier with respect to `self`. The
b039eaaf 471 /// implementor is responsible for ensuring that the returned name
1a4d82fc 472 /// is a valid DOT identifier.
54a0048b 473 fn node_id(&'a self, n: &Self::Node) -> Id<'a>;
1a4d82fc 474
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475 /// Maps `n` to one of the [graphviz `shape` names][1]. If `None`
476 /// is returned, no `shape` attribute is specified.
477 ///
478 /// [1]: http://www.graphviz.org/content/node-shapes
54a0048b 479 fn node_shape(&'a self, _node: &Self::Node) -> Option<LabelText<'a>> {
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480 None
481 }
482
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483 /// Maps `n` to a label that will be used in the rendered output.
484 /// The label need not be unique, and may be the empty string; the
485 /// default is just the output from `node_id`.
54a0048b 486 fn node_label(&'a self, n: &Self::Node) -> LabelText<'a> {
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487 LabelStr(self.node_id(n).name)
488 }
489
490 /// Maps `e` to a label that will be used in the rendered output.
491 /// The label need not be unique, and may be the empty string; the
492 /// default is in fact the empty string.
54a0048b 493 fn edge_label(&'a self, e: &Self::Edge) -> LabelText<'a> {
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494 let _ignored = e;
495 LabelStr("".into_cow())
496 }
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497
498 /// Maps `n` to a style that will be used in the rendered output.
54a0048b 499 fn node_style(&'a self, _n: &Self::Node) -> Style {
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500 Style::None
501 }
502
503 /// Maps `e` to a style that will be used in the rendered output.
54a0048b 504 fn edge_style(&'a self, _e: &Self::Edge) -> Style {
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505 Style::None
506 }
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507}
508
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509/// Escape tags in such a way that it is suitable for inclusion in a
510/// Graphviz HTML label.
511pub fn escape_html(s: &str) -> String {
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512 s.replace("&", "&amp;")
513 .replace("\"", "&quot;")
514 .replace("<", "&lt;")
515 .replace(">", "&gt;")
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516}
517
1a4d82fc 518impl<'a> LabelText<'a> {
e9174d1e 519 pub fn label<S: IntoCow<'a, str>>(s: S) -> LabelText<'a> {
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520 LabelStr(s.into_cow())
521 }
522
e9174d1e 523 pub fn escaped<S: IntoCow<'a, str>>(s: S) -> LabelText<'a> {
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524 EscStr(s.into_cow())
525 }
526
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527 pub fn html<S: IntoCow<'a, str>>(s: S) -> LabelText<'a> {
528 HtmlStr(s.into_cow())
529 }
530
531 fn escape_char<F>(c: char, mut f: F)
532 where F: FnMut(char)
533 {
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534 match c {
535 // not escaping \\, since Graphviz escString needs to
536 // interpret backslashes; see EscStr above.
537 '\\' => f(c),
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538 _ => {
539 for c in c.escape_default() {
540 f(c)
541 }
542 }
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543 }
544 }
545 fn escape_str(s: &str) -> String {
546 let mut out = String::with_capacity(s.len());
547 for c in s.chars() {
548 LabelText::escape_char(c, |c| out.push(c));
549 }
550 out
551 }
552
553 /// Renders text as string suitable for a label in a .dot file.
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554 /// This includes quotes or suitable delimeters.
555 pub fn to_dot_string(&self) -> String {
1a4d82fc 556 match self {
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557 &LabelStr(ref s) => format!("\"{}\"", s.escape_default()),
558 &EscStr(ref s) => format!("\"{}\"", LabelText::escape_str(&s[..])),
559 &HtmlStr(ref s) => format!("<{}>", s),
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560 }
561 }
562
563 /// Decomposes content into string suitable for making EscStr that
564 /// yields same content as self. The result obeys the law
565 /// render(`lt`) == render(`EscStr(lt.pre_escaped_content())`) for
566 /// all `lt: LabelText`.
85aaf69f 567 fn pre_escaped_content(self) -> Cow<'a, str> {
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568 match self {
569 EscStr(s) => s,
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570 LabelStr(s) => {
571 if s.contains('\\') {
572 (&*s).escape_default().into_cow()
573 } else {
574 s
575 }
576 }
e9174d1e 577 HtmlStr(s) => s,
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578 }
579 }
580
581 /// Puts `prefix` on a line above this label, with a blank line separator.
582 pub fn prefix_line(self, prefix: LabelText) -> LabelText<'static> {
583 prefix.suffix_line(self)
584 }
585
586 /// Puts `suffix` on a line below this label, with a blank line separator.
587 pub fn suffix_line(self, suffix: LabelText) -> LabelText<'static> {
588 let mut prefix = self.pre_escaped_content().into_owned();
589 let suffix = suffix.pre_escaped_content();
590 prefix.push_str(r"\n\n");
85aaf69f 591 prefix.push_str(&suffix[..]);
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592 EscStr(prefix.into_cow())
593 }
594}
595
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596pub type Nodes<'a,N> = Cow<'a,[N]>;
597pub type Edges<'a,E> = Cow<'a,[E]>;
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598
599// (The type parameters in GraphWalk should be associated items,
600// when/if Rust supports such.)
601
602/// GraphWalk is an abstraction over a directed graph = (nodes,edges)
603/// made up of node handles `N` and edge handles `E`, where each `E`
604/// can be mapped to its source and target nodes.
605///
606/// The lifetime parameter `'a` is exposed in this trait (rather than
607/// introduced as a generic parameter on each method declaration) so
608/// that a client impl can choose `N` and `E` that have substructure
609/// that is bound by the self lifetime `'a`.
610///
611/// The `nodes` and `edges` method each return instantiations of
b039eaaf 612/// `Cow<[T]>` to leave implementors the freedom to create
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613/// entirely new vectors or to pass back slices into internally owned
614/// vectors.
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615pub trait GraphWalk<'a> {
616 type Node: Clone;
617 type Edge: Clone;
618
1a4d82fc 619 /// Returns all the nodes in this graph.
54a0048b 620 fn nodes(&'a self) -> Nodes<'a, Self::Node>;
1a4d82fc 621 /// Returns all of the edges in this graph.
54a0048b 622 fn edges(&'a self) -> Edges<'a, Self::Edge>;
1a4d82fc 623 /// The source node for `edge`.
54a0048b 624 fn source(&'a self, edge: &Self::Edge) -> Self::Node;
1a4d82fc 625 /// The target node for `edge`.
54a0048b 626 fn target(&'a self, edge: &Self::Edge) -> Self::Node;
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627}
628
c34b1796 629#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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630pub enum RenderOption {
631 NoEdgeLabels,
632 NoNodeLabels,
c1a9b12d
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633 NoEdgeStyles,
634 NoNodeStyles,
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635}
636
637/// Returns vec holding all the default render options.
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638pub fn default_options() -> Vec<RenderOption> {
639 vec![]
640}
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641
642/// Renders directed graph `g` into the writer `w` in DOT syntax.
643/// (Simple wrapper around `render_opts` that passes a default set of options.)
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644pub fn render<'a,N,E,G,W>(g: &'a G, w: &mut W) -> io::Result<()>
645 where N: Clone + 'a,
646 E: Clone + 'a,
647 G: Labeller<'a, Node=N, Edge=E> + GraphWalk<'a, Node=N, Edge=E>,
648 W: Write
649{
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650 render_opts(g, w, &[])
651}
652
653/// Renders directed graph `g` into the writer `w` in DOT syntax.
654/// (Main entry point for the library.)
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655pub fn render_opts<'a, N, E, G, W>(g: &'a G,
656 w: &mut W,
657 options: &[RenderOption])
658 -> io::Result<()>
659 where N: Clone + 'a,
660 E: Clone + 'a,
661 G: Labeller<'a, Node=N, Edge=E> + GraphWalk<'a, Node=N, Edge=E>,
662 W: Write
663{
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664 fn writeln<W: Write>(w: &mut W, arg: &[&str]) -> io::Result<()> {
665 for &s in arg {
54a0048b 666 w.write_all(s.as_bytes())?;
e9174d1e 667 }
c34b1796 668 write!(w, "\n")
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669 }
670
e9174d1e 671 fn indent<W: Write>(w: &mut W) -> io::Result<()> {
c34b1796 672 w.write_all(b" ")
1a4d82fc
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673 }
674
54a0048b 675 writeln(w, &["digraph ", g.graph_id().as_slice(), " {"])?;
62682a34 676 for n in g.nodes().iter() {
54a0048b 677 indent(w)?;
1a4d82fc 678 let id = g.node_id(n);
c1a9b12d 679
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680 let escaped = &g.node_label(n).to_dot_string();
681 let shape;
c1a9b12d
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682
683 let mut text = vec![id.as_slice()];
684
685 if !options.contains(&RenderOption::NoNodeLabels) {
e9174d1e 686 text.push("[label=");
c1a9b12d 687 text.push(escaped);
e9174d1e 688 text.push("]");
1a4d82fc 689 }
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690
691 let style = g.node_style(n);
692 if !options.contains(&RenderOption::NoNodeStyles) && style != Style::None {
693 text.push("[style=\"");
694 text.push(style.as_slice());
695 text.push("\"]");
696 }
697
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698 if let Some(s) = g.node_shape(n) {
699 shape = s.to_dot_string();
700 text.push("[shape=");
701 text.push(&shape);
702 text.push("]");
703 }
704
c1a9b12d 705 text.push(";");
54a0048b 706 writeln(w, &text)?;
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707 }
708
62682a34 709 for e in g.edges().iter() {
e9174d1e 710 let escaped_label = &g.edge_label(e).to_dot_string();
54a0048b 711 indent(w)?;
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712 let source = g.source(e);
713 let target = g.target(e);
714 let source_id = g.node_id(&source);
715 let target_id = g.node_id(&target);
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716
717 let mut text = vec![source_id.as_slice(), " -> ", target_id.as_slice()];
718
719 if !options.contains(&RenderOption::NoEdgeLabels) {
e9174d1e 720 text.push("[label=");
c1a9b12d 721 text.push(escaped_label);
e9174d1e 722 text.push("]");
c1a9b12d
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723 }
724
725 let style = g.edge_style(e);
726 if !options.contains(&RenderOption::NoEdgeStyles) && style != Style::None {
727 text.push("[style=\"");
728 text.push(style.as_slice());
729 text.push("\"]");
1a4d82fc 730 }
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731
732 text.push(";");
54a0048b 733 writeln(w, &text)?;
1a4d82fc
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734 }
735
736 writeln(w, &["}"])
737}
738
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739pub trait IntoCow<'a, B: ?Sized> where B: ToOwned {
740 fn into_cow(self) -> Cow<'a, B>;
741}
742
743impl<'a> IntoCow<'a, str> for String {
744 fn into_cow(self) -> Cow<'a, str> {
745 Cow::Owned(self)
746 }
747}
748
749impl<'a> IntoCow<'a, str> for &'a str {
750 fn into_cow(self) -> Cow<'a, str> {
751 Cow::Borrowed(self)
752 }
753}
754
755impl<'a, T: Clone> IntoCow<'a, [T]> for Vec<T> {
756 fn into_cow(self) -> Cow<'a, [T]> {
757 Cow::Owned(self)
758 }
759}
760
761impl<'a, T: Clone> IntoCow<'a, [T]> for &'a [T] {
762 fn into_cow(self) -> Cow<'a, [T]> {
763 Cow::Borrowed(self)
764 }
765}
766
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767#[cfg(test)]
768mod tests {
769 use self::NodeLabels::*;
c1a9b12d 770 use super::{Id, Labeller, Nodes, Edges, GraphWalk, render, Style};
e9174d1e 771 use super::LabelText::{self, LabelStr, EscStr, HtmlStr};
c34b1796
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772 use std::io;
773 use std::io::prelude::*;
9cc50fc6 774 use IntoCow;
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775
776 /// each node is an index in a vector in the graph.
c34b1796 777 type Node = usize;
1a4d82fc 778 struct Edge {
c1a9b12d
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779 from: usize,
780 to: usize,
781 label: &'static str,
782 style: Style,
1a4d82fc
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783 }
784
c1a9b12d 785 fn edge(from: usize, to: usize, label: &'static str, style: Style) -> Edge {
92a42be0
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786 Edge {
787 from: from,
788 to: to,
789 label: label,
790 style: style,
791 }
1a4d82fc
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792 }
793
794 struct LabelledGraph {
795 /// The name for this graph. Used for labelling generated `digraph`.
796 name: &'static str,
797
798 /// Each node is an index into `node_labels`; these labels are
799 /// used as the label text for each node. (The node *names*,
800 /// which are unique identifiers, are derived from their index
801 /// in this array.)
802 ///
803 /// If a node maps to None here, then just use its name as its
804 /// text.
805 node_labels: Vec<Option<&'static str>>,
806
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807 node_styles: Vec<Style>,
808
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809 /// Each edge relates a from-index to a to-index along with a
810 /// label; `edges` collects them.
811 edges: Vec<Edge>,
812 }
813
814 // A simple wrapper around LabelledGraph that forces the labels to
815 // be emitted as EscStr.
816 struct LabelledGraphWithEscStrs {
e9174d1e 817 graph: LabelledGraph,
1a4d82fc
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818 }
819
820 enum NodeLabels<L> {
821 AllNodesLabelled(Vec<L>),
c34b1796 822 UnlabelledNodes(usize),
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823 SomeNodesLabelled(Vec<Option<L>>),
824 }
825
826 type Trivial = NodeLabels<&'static str>;
827
828 impl NodeLabels<&'static str> {
829 fn to_opt_strs(self) -> Vec<Option<&'static str>> {
830 match self {
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831 UnlabelledNodes(len) => vec![None; len],
832 AllNodesLabelled(lbls) => lbls.into_iter().map(|l| Some(l)).collect(),
833 SomeNodesLabelled(lbls) => lbls.into_iter().collect(),
1a4d82fc
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834 }
835 }
c1a9b12d
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836
837 fn len(&self) -> usize {
838 match self {
839 &UnlabelledNodes(len) => len,
840 &AllNodesLabelled(ref lbls) => lbls.len(),
841 &SomeNodesLabelled(ref lbls) => lbls.len(),
842 }
843 }
1a4d82fc
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844 }
845
846 impl LabelledGraph {
847 fn new(name: &'static str,
848 node_labels: Trivial,
c1a9b12d 849 edges: Vec<Edge>,
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850 node_styles: Option<Vec<Style>>)
851 -> LabelledGraph {
c1a9b12d 852 let count = node_labels.len();
1a4d82fc
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853 LabelledGraph {
854 name: name,
855 node_labels: node_labels.to_opt_strs(),
c1a9b12d
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856 edges: edges,
857 node_styles: match node_styles {
858 Some(nodes) => nodes,
859 None => vec![Style::None; count],
e9174d1e 860 },
1a4d82fc
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861 }
862 }
863 }
864
865 impl LabelledGraphWithEscStrs {
866 fn new(name: &'static str,
867 node_labels: Trivial,
e9174d1e
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868 edges: Vec<Edge>)
869 -> LabelledGraphWithEscStrs {
870 LabelledGraphWithEscStrs { graph: LabelledGraph::new(name, node_labels, edges, None) }
1a4d82fc
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871 }
872 }
873
874 fn id_name<'a>(n: &Node) -> Id<'a> {
875 Id::new(format!("N{}", *n)).unwrap()
876 }
877
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878 impl<'a> Labeller<'a> for LabelledGraph {
879 type Node = Node;
880 type Edge = &'a Edge;
1a4d82fc 881 fn graph_id(&'a self) -> Id<'a> {
85aaf69f 882 Id::new(&self.name[..]).unwrap()
1a4d82fc
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883 }
884 fn node_id(&'a self, n: &Node) -> Id<'a> {
885 id_name(n)
886 }
887 fn node_label(&'a self, n: &Node) -> LabelText<'a> {
888 match self.node_labels[*n] {
889 Some(ref l) => LabelStr(l.into_cow()),
e9174d1e 890 None => LabelStr(id_name(n).name()),
1a4d82fc
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891 }
892 }
e9174d1e 893 fn edge_label(&'a self, e: &&'a Edge) -> LabelText<'a> {
1a4d82fc
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894 LabelStr(e.label.into_cow())
895 }
c1a9b12d
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896 fn node_style(&'a self, n: &Node) -> Style {
897 self.node_styles[*n]
898 }
e9174d1e 899 fn edge_style(&'a self, e: &&'a Edge) -> Style {
c1a9b12d
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900 e.style
901 }
1a4d82fc
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902 }
903
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904 impl<'a> Labeller<'a> for LabelledGraphWithEscStrs {
905 type Node = Node;
906 type Edge = &'a Edge;
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907 fn graph_id(&'a self) -> Id<'a> {
908 self.graph.graph_id()
909 }
910 fn node_id(&'a self, n: &Node) -> Id<'a> {
911 self.graph.node_id(n)
912 }
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913 fn node_label(&'a self, n: &Node) -> LabelText<'a> {
914 match self.graph.node_label(n) {
e9174d1e 915 LabelStr(s) | EscStr(s) | HtmlStr(s) => EscStr(s),
1a4d82fc
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916 }
917 }
e9174d1e 918 fn edge_label(&'a self, e: &&'a Edge) -> LabelText<'a> {
1a4d82fc 919 match self.graph.edge_label(e) {
e9174d1e 920 LabelStr(s) | EscStr(s) | HtmlStr(s) => EscStr(s),
1a4d82fc
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921 }
922 }
923 }
924
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925 impl<'a> GraphWalk<'a> for LabelledGraph {
926 type Node = Node;
927 type Edge = &'a Edge;
e9174d1e 928 fn nodes(&'a self) -> Nodes<'a, Node> {
85aaf69f 929 (0..self.node_labels.len()).collect()
1a4d82fc 930 }
e9174d1e 931 fn edges(&'a self) -> Edges<'a, &'a Edge> {
1a4d82fc
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932 self.edges.iter().collect()
933 }
e9174d1e 934 fn source(&'a self, edge: &&'a Edge) -> Node {
1a4d82fc
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935 edge.from
936 }
e9174d1e 937 fn target(&'a self, edge: &&'a Edge) -> Node {
1a4d82fc
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938 edge.to
939 }
940 }
941
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942 impl<'a> GraphWalk<'a> for LabelledGraphWithEscStrs {
943 type Node = Node;
944 type Edge = &'a Edge;
e9174d1e 945 fn nodes(&'a self) -> Nodes<'a, Node> {
1a4d82fc
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946 self.graph.nodes()
947 }
e9174d1e 948 fn edges(&'a self) -> Edges<'a, &'a Edge> {
1a4d82fc
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949 self.graph.edges()
950 }
e9174d1e 951 fn source(&'a self, edge: &&'a Edge) -> Node {
1a4d82fc
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952 edge.from
953 }
e9174d1e 954 fn target(&'a self, edge: &&'a Edge) -> Node {
1a4d82fc
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955 edge.to
956 }
957 }
958
c34b1796 959 fn test_input(g: LabelledGraph) -> io::Result<String> {
1a4d82fc
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960 let mut writer = Vec::new();
961 render(&g, &mut writer).unwrap();
c34b1796 962 let mut s = String::new();
54a0048b 963 Read::read_to_string(&mut &*writer, &mut s)?;
c34b1796 964 Ok(s)
1a4d82fc
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965 }
966
967 // All of the tests use raw-strings as the format for the expected outputs,
968 // so that you can cut-and-paste the content into a .dot file yourself to
969 // see what the graphviz visualizer would produce.
970
971 #[test]
972 fn empty_graph() {
e9174d1e 973 let labels: Trivial = UnlabelledNodes(0);
c1a9b12d 974 let r = test_input(LabelledGraph::new("empty_graph", labels, vec![], None));
1a4d82fc
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975 assert_eq!(r.unwrap(),
976r#"digraph empty_graph {
977}
978"#);
979 }
980
981 #[test]
982 fn single_node() {
e9174d1e 983 let labels: Trivial = UnlabelledNodes(1);
c1a9b12d 984 let r = test_input(LabelledGraph::new("single_node", labels, vec![], None));
1a4d82fc
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985 assert_eq!(r.unwrap(),
986r#"digraph single_node {
987 N0[label="N0"];
988}
989"#);
990 }
991
c1a9b12d
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992 #[test]
993 fn single_node_with_style() {
e9174d1e 994 let labels: Trivial = UnlabelledNodes(1);
c1a9b12d
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995 let styles = Some(vec![Style::Dashed]);
996 let r = test_input(LabelledGraph::new("single_node", labels, vec![], styles));
997 assert_eq!(r.unwrap(),
998r#"digraph single_node {
999 N0[label="N0"][style="dashed"];
1000}
1001"#);
1002 }
1003
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1004 #[test]
1005 fn single_edge() {
e9174d1e
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1006 let labels: Trivial = UnlabelledNodes(2);
1007 let result = test_input(LabelledGraph::new("single_edge",
1008 labels,
1009 vec![edge(0, 1, "E", Style::None)],
1010 None));
1a4d82fc
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1011 assert_eq!(result.unwrap(),
1012r#"digraph single_edge {
1013 N0[label="N0"];
1014 N1[label="N1"];
1015 N0 -> N1[label="E"];
1016}
1017"#);
1018 }
1019
c1a9b12d
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1020 #[test]
1021 fn single_edge_with_style() {
e9174d1e
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1022 let labels: Trivial = UnlabelledNodes(2);
1023 let result = test_input(LabelledGraph::new("single_edge",
1024 labels,
1025 vec![edge(0, 1, "E", Style::Bold)],
1026 None));
c1a9b12d
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1027 assert_eq!(result.unwrap(),
1028r#"digraph single_edge {
1029 N0[label="N0"];
1030 N1[label="N1"];
1031 N0 -> N1[label="E"][style="bold"];
1032}
1033"#);
1034 }
1035
1a4d82fc
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1036 #[test]
1037 fn test_some_labelled() {
e9174d1e 1038 let labels: Trivial = SomeNodesLabelled(vec![Some("A"), None]);
c1a9b12d 1039 let styles = Some(vec![Style::None, Style::Dotted]);
e9174d1e
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1040 let result = test_input(LabelledGraph::new("test_some_labelled",
1041 labels,
1042 vec![edge(0, 1, "A-1", Style::None)],
1043 styles));
1a4d82fc
JJ
1044 assert_eq!(result.unwrap(),
1045r#"digraph test_some_labelled {
1046 N0[label="A"];
c1a9b12d 1047 N1[label="N1"][style="dotted"];
1a4d82fc
JJ
1048 N0 -> N1[label="A-1"];
1049}
1050"#);
1051 }
1052
1053 #[test]
1054 fn single_cyclic_node() {
e9174d1e
SL
1055 let labels: Trivial = UnlabelledNodes(1);
1056 let r = test_input(LabelledGraph::new("single_cyclic_node",
1057 labels,
1058 vec![edge(0, 0, "E", Style::None)],
1059 None));
1a4d82fc
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1060 assert_eq!(r.unwrap(),
1061r#"digraph single_cyclic_node {
1062 N0[label="N0"];
1063 N0 -> N0[label="E"];
1064}
1065"#);
1066 }
1067
1068 #[test]
1069 fn hasse_diagram() {
92a42be0 1070 let labels = AllNodesLabelled(vec!["{x,y}", "{x}", "{y}", "{}"]);
e9174d1e
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1071 let r = test_input(LabelledGraph::new("hasse_diagram",
1072 labels,
1073 vec![edge(0, 1, "", Style::None),
1074 edge(0, 2, "", Style::None),
1075 edge(1, 3, "", Style::None),
1076 edge(2, 3, "", Style::None)],
1077 None));
1a4d82fc
JJ
1078 assert_eq!(r.unwrap(),
1079r#"digraph hasse_diagram {
1080 N0[label="{x,y}"];
1081 N1[label="{x}"];
1082 N2[label="{y}"];
1083 N3[label="{}"];
1084 N0 -> N1[label=""];
1085 N0 -> N2[label=""];
1086 N1 -> N3[label=""];
1087 N2 -> N3[label=""];
1088}
1089"#);
1090 }
1091
1092 #[test]
1093 fn left_aligned_text() {
92a42be0 1094 let labels = AllNodesLabelled(vec![
1a4d82fc
JJ
1095 "if test {\
1096 \\l branch1\
1097 \\l} else {\
1098 \\l branch2\
1099 \\l}\
1100 \\lafterward\
1101 \\l",
1102 "branch1",
1103 "branch2",
92a42be0 1104 "afterward"]);
1a4d82fc
JJ
1105
1106 let mut writer = Vec::new();
1107
e9174d1e
SL
1108 let g = LabelledGraphWithEscStrs::new("syntax_tree",
1109 labels,
1110 vec![edge(0, 1, "then", Style::None),
1111 edge(0, 2, "else", Style::None),
1112 edge(1, 3, ";", Style::None),
1113 edge(2, 3, ";", Style::None)]);
1a4d82fc
JJ
1114
1115 render(&g, &mut writer).unwrap();
c34b1796
AL
1116 let mut r = String::new();
1117 Read::read_to_string(&mut &*writer, &mut r).unwrap();
1a4d82fc 1118
c34b1796 1119 assert_eq!(r,
1a4d82fc
JJ
1120r#"digraph syntax_tree {
1121 N0[label="if test {\l branch1\l} else {\l branch2\l}\lafterward\l"];
1122 N1[label="branch1"];
1123 N2[label="branch2"];
1124 N3[label="afterward"];
1125 N0 -> N1[label="then"];
1126 N0 -> N2[label="else"];
1127 N1 -> N3[label=";"];
1128 N2 -> N3[label=";"];
1129}
1130"#);
1131 }
1132
1133 #[test]
1134 fn simple_id_construction() {
1135 let id1 = Id::new("hello");
1136 match id1 {
e9174d1e
SL
1137 Ok(_) => {}
1138 Err(..) => panic!("'hello' is not a valid value for id anymore"),
1a4d82fc
JJ
1139 }
1140 }
1141
1142 #[test]
1143 fn badly_formatted_id() {
1144 let id2 = Id::new("Weird { struct : ure } !!!");
1145 match id2 {
1146 Ok(_) => panic!("graphviz id suddenly allows spaces, brackets and stuff"),
e9174d1e 1147 Err(..) => {}
1a4d82fc
JJ
1148 }
1149 }
1150}