Mike Gerwitz

Activist for User Freedom

aboutsummaryrefslogtreecommitdiffstats
blob: 2cf0100d45ae881fb0b4011927515d0e0c91acf4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
// Proof-of-concept TAME linker
//
//  Copyright (C) 2014-2019 Ryan Specialty Group, LLC.
//
//  This program 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.
//
//  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

//! **This is a poorly-written proof of concept; do not use!**  It has been
//! banished to its own file to try to make that more clear.

use fixedbitset::FixedBitSet;
use petgraph::graph::{DiGraph, EdgeIndex, Neighbors, NodeIndex};
use petgraph::visit::{DfsPostOrder, GraphBase, IntoNeighbors, Visitable};
use quick_xml::events::Event;
use quick_xml::Reader;
use std::collections::hash_map::{Entry, Iter};
use std::collections::{HashMap, HashSet};
use std::error::Error;
use std::fs;
use std::io::BufRead;
use std::ops::{Deref, Index};
use std::rc::Rc;

// The term "sym" is used throughout because it's easier to search for that
// in source code than "symbol", which is a generic term with many different
// meanings.

// if mutability is needed:
//#[derive(Debug)]
//struct SymRecord {
//    data: SymData,
//
//    // the idea is to keep the index encapsulated so that nothing else can
//    // ever hold a reference to it, ensuring that it's freed when the node
//    // is removed
//    index: Rc<RefCell<Option<NodeIndex>>>,
//}

#[derive(Debug)]
struct SymData {
    name: Rc<str>,
}

type DepGraphNode = SymEntry;
type DepGraphEdge = ();

struct DepGraph {
    graph: DiGraph<DepGraphNode, DepGraphEdge>,

    // serves as both a string internment system and graph indexer
    index: HashMap<Rc<str>, SymRef>,
    // if removals are permitted:
    //index: HashMap<Rc<str>, Weak<RefCell<Option<NodeIndex>>>>,
}

// This encapsulates the underlying Graph to enforce certain
// assumptions.  For example, we do not permit removing nodes because that
// would invalidate the NodeIndex reference in the index, which would then
// require workarounds like the commented-out code above and below.
//
// While Petgraph's use of indexes to represent graph and edge references
// makes it easy to bypass the borrow checker, it does just that---it's no
// different than a pointer reference (albeit guaranteed to safely reference
// a node rather than an arbitrary memory location) that can change out from
// under you at any moment.  As such, much of the planning that went into
// this was determining how to best mitigate that.
//
// The linker has certain needs that may differ as the compiler evolves, so
// it may be desirable to permit deletions in the future.  In the meantime,
// if a node needs to be deleted, we can simply remove all edges from it and
// possibly mark it in a way that states it was removed.
//
// This graph uses a separate map to serve a dual role: a string internment
// system and an indexer by symbol name.  This will have to evolve in the
// future as the graph ends up containing more stuff.
//
// This is currently called a dependency graph, since that's what we're
// using it for, but in the future the compiler will also use it as an IR,
// so this will likely be renamed.
impl DepGraph {
    fn new() -> Self {
        Self {
            // TODO: with_capacity
            graph: DiGraph::new(),
            index: HashMap::new(),
        }
    }

    fn declare(&mut self, name: &str) -> SymRef {
        match self.index.entry(name.into()) {
            Entry::Occupied(o) => *o.get(),
            Entry::Vacant(v) => {
                let entry = SymEntry::MissingSym {
                    name: Rc::clone(v.key()),
                };

                let index = SymRef(self.graph.add_node(entry));
                v.insert(index);

                index
            }
        }
    }

    // will not duplicate dependencies if they already exist
    fn declare_dep(&mut self, symbol: SymRef, dep: SymRef) -> () {
        self.graph.update_edge(*symbol, *dep, ());
    }

    fn lookup(&self, name: &str) -> Option<SymRef> {
        self.index.get(name.into()).map(|index| *index)
    }

    fn index_iter(&self) -> Iter<Rc<str>, SymRef> {
        self.index.iter()
    }

    // POC when removals were permitted:
    //fn add_symbol(&mut self, sym: SymData) -> NodeIndex {
    //    let name = Rc::clone(&sym.name);
    //    let record = SymRecord { data: sym, index: Rc::new(RefCell::new(None)) };
    //    let index = self.graph.add_node(record);

    //    let index = Rc::downgrade(&self.graph[index].index);
    //    self.graph[index].index.replace(Some(index));

    //    self.index.insert(name, index);
    //    index
    //}
}

impl GraphBase for DepGraph {
    type NodeId = NodeIndex;
    type EdgeId = EdgeIndex;
}

impl Visitable for DepGraph {
    type Map = FixedBitSet;

    fn visit_map(&self) -> Self::Map {
        self.graph.visit_map()
    }

    fn reset_map(&self, map: &mut Self::Map) {
        self.graph.reset_map(map)
    }
}

impl<'a> IntoNeighbors for &'a DepGraph {
    type Neighbors = Neighbors<'a, DepGraphEdge>;

    fn neighbors(self, n: Self::NodeId) -> Self::Neighbors {
        self.graph.neighbors(n)
    }
}

impl Index<SymRef> for DepGraph {
    type Output = DepGraphNode;

    fn index(&self, index: SymRef) -> &Self::Output {
        &self.graph[*index]
    }
}

// TODO: we may not to allow this; using SymRef could be a means to
// guarantee that a lookup has occurred and that it actually exists.  We
// don't need this if we set NodeId = SymRef in GraphBase, but that requires
// implementing other traits as well.
impl Index<NodeIndex> for DepGraph {
    type Output = DepGraphNode;

    fn index(&self, index: NodeIndex) -> &Self::Output {
        &self.graph[index]
    }
}

#[derive(Debug, Clone, Copy, PartialEq)]
struct SymRef(NodeIndex);

impl From<SymRef> for NodeIndex {
    fn from(symref: SymRef) -> Self {
        *symref
    }
}

impl From<NodeIndex> for SymRef {
    fn from(index: NodeIndex) -> Self {
        Self(index)
    }
}

impl Deref for SymRef {
    type Target = NodeIndex;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

#[derive(Debug, PartialEq)]
enum SymEntry {
    MissingSym { name: Rc<str> },
}

pub fn main() -> Result<(), Box<dyn Error>> {
    let mut pkgs_seen = HashSet::<String>::new();
    let mut fragments = HashMap::<String, String>::new();
    let mut depgraph = DepGraph::new();

    let package_path = std::env::args().nth(1).expect("Missing argument");
    let abs_path = fs::canonicalize(package_path).unwrap();

    println!("WARNING: This is proof-of-concept; do not use!");

    load_xmlo(
        &abs_path.to_str().unwrap().to_string(),
        &mut pkgs_seen,
        &mut fragments,
        &mut depgraph,
    )?;

    //    println!(
    //        "Graph {:?}",
    //        depgraph
    //            .graph
    //            .raw_nodes()
    //            .iter()
    //            .map(|node| &node.weight)
    //            .collect::<Vec<_>>()
    //    );

    let sorted = sort_deps(&depgraph);

    println!("Sorted ({}): {:?}", sorted.len(), sorted);

    Ok(())
}

fn load_xmlo<'a>(
    path_str: &'a str,
    pkgs_seen: &mut HashSet<String>,
    fragments: &mut HashMap<String, String>,
    depgraph: &mut DepGraph,
) -> Result<(), Box<dyn Error>> {
    let path = fs::canonicalize(path_str)?;
    let path_str = path.to_str().unwrap();

    if !pkgs_seen.insert(path_str.to_string()) {
        return Ok(());
    }

    println!("processing {}", path_str);

    let mut found = HashSet::<String>::new();

    match Reader::from_file(&path) {
        Ok(mut reader) => loop {
            let mut buf = Vec::new();

            // we know that the XML produced by Saxon is valid
            reader.check_end_names(false);

            match reader.read_event(&mut buf) {
                Ok(Event::Start(ele)) | Ok(Event::Empty(ele)) => {
                    let mut attrs = ele.attributes();
                    let mut filtered =
                        attrs.with_checks(false).filter_map(Result::ok);

                    match ele.name() {
                        b"preproc:sym-dep" => filtered
                            .find(|attr| attr.key == b"name")
                            .map(|attr| attr.value)
                            .and_then(|mut name| {
                                read_deps(&mut reader, depgraph, name.to_mut())
                            })
                            .ok_or("Missing name"),

                        b"preproc:sym" => {
                            filtered
                                .find(|attr| attr.key == b"src")
                                .map(|attr| attr.value.to_owned())
                                .and_then(|src| {
                                    let path_str =
                                        std::str::from_utf8(&src).unwrap();

                                    found.insert(path_str.to_string());
                                    Some(())
                                });
                            Ok(())
                        }

                        b"preproc:fragment" => filtered
                            .find(|attr| attr.key == b"id")
                            .map(|attr| String::from_utf8(attr.value.to_vec()))
                            .and_then(|id| {
                                let fragment = reader
                                    .read_text(ele.name(), &mut Vec::new())
                                    .unwrap_or("".to_string());

                                fragments.insert(id.unwrap(), fragment);
                                Some(())
                            })
                            .ok_or("Missing fragment id"),
                        _ => Ok(()),
                    }
                }
                Ok(Event::End(ele)) => {
                    match ele.name() {
                        // We don't need to read any further than the end of
                        // the fragments (symtable, sym-deps, fragments)
                        b"preproc:fragments" => break (),
                        _ => Ok(()),
                    }
                }
                Ok(Event::Eof) => break (),
                Err(e) => {
                    panic!("Error at {}: {:?}", reader.buffer_position(), e);
                }
                _ => Ok(()),
            }
            .unwrap_or_else(|r| panic!("Parse error: {:?}", r));

            buf.clear();
        },
        Err(e) => panic!("Error {:?}", e),
    }

    let mut dir = path.clone();
    dir.pop();

    for relpath in found.iter() {
        let mut path_buf = dir.clone();
        path_buf.push(relpath);
        path_buf.set_extension("xmlo");

        //println!("Trying {:?}", path_buf);
        let path_abs = path_buf.canonicalize().unwrap();
        let path = path_abs.to_str().unwrap();

        load_xmlo(path, pkgs_seen, fragments, depgraph)?;
    }

    Ok(())
}

fn read_deps<B>(
    reader: &mut Reader<B>,
    depgraph: &mut DepGraph,
    name: &[u8],
) -> Option<()>
where
    B: BufRead,
{
    // TODO: API needs to expose whether a symbol is already known so that
    // we can warn on them
    // note: using from_utf8_unchecked here did _not_ improve performance
    let sym_node = depgraph.declare(std::str::from_utf8(name).unwrap());

    //println!("processing deps for {}", sym_name);

    loop {
        match reader.read_event(&mut Vec::new()) {
            Ok(Event::Start(ele)) | Ok(Event::Empty(ele)) => {
                let mut attrs = ele.attributes();
                let mut filtered =
                    attrs.with_checks(false).filter_map(Result::ok);

                filtered.find(|attr| attr.key == b"name").and_then(
                    |mut attr| {
                        let name = attr.value.to_mut();
                        let str = std::str::from_utf8(name).unwrap();

                        let dep_node = depgraph.declare(&str);
                        depgraph.declare_dep(sym_node, dep_node);

                        Some(())
                    },
                );

                //println!("{:?}", ele.attributes().collect::<Vec<_>>());
            }

            Ok(Event::Eof) | Ok(Event::End(_)) => break Some(()),

            Err(e) => {
                panic!("Error at {}: {:?}", reader.buffer_position(), e);
            }

            _ => (),
        }
    }
}

fn sort_deps(depgraph: &DepGraph) -> Vec<&SymEntry> {
    // @type=meta, @preproc:elig-class-yields
    // @type={ret}map{,:head,:tail}

    let roots = discover_roots(depgraph);

    // This is technically a topological sort, but functions have
    // cycles.  Once we have more symbol metadata, we can filter them out
    // and actually invoke toposort.
    let mut dfs = DfsPostOrder::empty(&depgraph);
    let mut sorted = Vec::new();

    // TODO: we'll be processing various roots separately
    for index in roots {
        dfs.stack.push(*index);
    }

    while let Some(index) = dfs.next(&depgraph) {
        sorted.push(&depgraph[index]);
    }

    sorted
}

fn discover_roots(depgraph: &DepGraph) -> Vec<SymRef> {
    // TODO: filter_map
    let mut map_syms = depgraph
        .index_iter()
        .filter(|(key, _)| {
            key.starts_with(":map:") || key.starts_with(":retmap:")
        })
        .map(|(_, value)| *value)
        .collect::<Vec<_>>();

    let mut roots = vec!["___yield", "___worksheet"]
        .iter()
        .filter_map(|sym| depgraph.lookup(sym))
        .collect::<Vec<_>>();

    roots.append(&mut map_syms);

    //println!(
    //    "found roots: {:?}",
    //    roots
    //        .iter()
    //        .map(|index| &depgraph.graph[*index])
    //        .collect::<Vec<_>>()
    //);

    roots
}

#[cfg(test)]
mod test {
    #[test]
    fn placeholder() {}
}