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
//! Calculates information used for the --show-coverage flag.
use crate::clean;
use crate::core::DocContext;
use crate::html::markdown::{find_testable_code, ErrorCodes};
use crate::passes::check_doc_test_visibility::{should_have_doc_example, Tests};
use crate::passes::Pass;
use crate::visit::DocVisitor;
use rustc_hir as hir;
use rustc_lint::builtin::MISSING_DOCS;
use rustc_middle::lint::LintLevelSource;
use rustc_middle::ty::DefIdTree;
use rustc_session::lint;
use rustc_span::FileName;
use serde::Serialize;

use std::collections::BTreeMap;
use std::ops;

pub(crate) const CALCULATE_DOC_COVERAGE: Pass = Pass {
    name: "calculate-doc-coverage",
    run: calculate_doc_coverage,
    description: "counts the number of items with and without documentation",
};

fn calculate_doc_coverage(krate: clean::Crate, ctx: &mut DocContext<'_>) -> clean::Crate {
    let mut calc = CoverageCalculator { items: Default::default(), ctx };
    calc.visit_crate(&krate);

    calc.print_results();

    krate
}

#[derive(Default, Copy, Clone, Serialize, Debug)]
struct ItemCount {
    total: u64,
    with_docs: u64,
    total_examples: u64,
    with_examples: u64,
}

impl ItemCount {
    fn count_item(
        &mut self,
        has_docs: bool,
        has_doc_example: bool,
        should_have_doc_examples: bool,
        should_have_docs: bool,
    ) {
        if has_docs || should_have_docs {
            self.total += 1;
        }

        if has_docs {
            self.with_docs += 1;
        }
        if should_have_doc_examples || has_doc_example {
            self.total_examples += 1;
        }
        if has_doc_example {
            self.with_examples += 1;
        }
    }

    fn percentage(&self) -> Option<f64> {
        if self.total > 0 {
            Some((self.with_docs as f64 * 100.0) / self.total as f64)
        } else {
            None
        }
    }

    fn examples_percentage(&self) -> Option<f64> {
        if self.total_examples > 0 {
            Some((self.with_examples as f64 * 100.0) / self.total_examples as f64)
        } else {
            None
        }
    }
}

impl ops::Sub for ItemCount {
    type Output = Self;

    fn sub(self, rhs: Self) -> Self {
        ItemCount {
            total: self.total - rhs.total,
            with_docs: self.with_docs - rhs.with_docs,
            total_examples: self.total_examples - rhs.total_examples,
            with_examples: self.with_examples - rhs.with_examples,
        }
    }
}

impl ops::AddAssign for ItemCount {
    fn add_assign(&mut self, rhs: Self) {
        self.total += rhs.total;
        self.with_docs += rhs.with_docs;
        self.total_examples += rhs.total_examples;
        self.with_examples += rhs.with_examples;
    }
}

struct CoverageCalculator<'a, 'b> {
    items: BTreeMap<FileName, ItemCount>,
    ctx: &'a mut DocContext<'b>,
}

fn limit_filename_len(filename: String) -> String {
    let nb_chars = filename.chars().count();
    if nb_chars > 35 {
        "...".to_string()
            + &filename[filename.char_indices().nth(nb_chars - 32).map(|x| x.0).unwrap_or(0)..]
    } else {
        filename
    }
}

impl<'a, 'b> CoverageCalculator<'a, 'b> {
    fn to_json(&self) -> String {
        serde_json::to_string(
            &self
                .items
                .iter()
                .map(|(k, v)| (k.prefer_local().to_string(), v))
                .collect::<BTreeMap<String, &ItemCount>>(),
        )
        .expect("failed to convert JSON data to string")
    }

    fn print_results(&self) {
        let output_format = self.ctx.output_format;
        if output_format.is_json() {
            println!("{}", self.to_json());
            return;
        }
        let mut total = ItemCount::default();

        fn print_table_line() {
            println!("+-{0:->35}-+-{0:->10}-+-{0:->10}-+-{0:->10}-+-{0:->10}-+", "");
        }

        fn print_table_record(
            name: &str,
            count: ItemCount,
            percentage: f64,
            examples_percentage: f64,
        ) {
            println!(
                "| {:<35} | {:>10} | {:>9.1}% | {:>10} | {:>9.1}% |",
                name, count.with_docs, percentage, count.with_examples, examples_percentage,
            );
        }

        print_table_line();
        println!(
            "| {:<35} | {:>10} | {:>10} | {:>10} | {:>10} |",
            "File", "Documented", "Percentage", "Examples", "Percentage",
        );
        print_table_line();

        for (file, &count) in &self.items {
            if let Some(percentage) = count.percentage() {
                print_table_record(
                    &limit_filename_len(file.prefer_local().to_string_lossy().into()),
                    count,
                    percentage,
                    count.examples_percentage().unwrap_or(0.),
                );

                total += count;
            }
        }

        print_table_line();
        print_table_record(
            "Total",
            total,
            total.percentage().unwrap_or(0.0),
            total.examples_percentage().unwrap_or(0.0),
        );
        print_table_line();
    }
}

impl<'a, 'b> DocVisitor for CoverageCalculator<'a, 'b> {
    fn visit_item(&mut self, i: &clean::Item) {
        if !i.item_id.is_local() {
            // non-local items are skipped because they can be out of the users control,
            // especially in the case of trait impls, which rustdoc eagerly inlines
            return;
        }

        match *i.kind {
            clean::StrippedItem(..) => {
                // don't count items in stripped modules
                return;
            }
            // docs on `use` and `extern crate` statements are not displayed, so they're not
            // worth counting
            clean::ImportItem(..) | clean::ExternCrateItem { .. } => {}
            // Don't count trait impls, the missing-docs lint doesn't so we shouldn't either.
            // Inherent impls *can* be documented, and those docs show up, but in most cases it
            // doesn't make sense, as all methods on a type are in one single impl block
            clean::ImplItem(_) => {}
            _ => {
                let has_docs = !i.attrs.doc_strings.is_empty();
                let mut tests = Tests { found_tests: 0 };

                find_testable_code(
                    &i.attrs.collapsed_doc_value().unwrap_or_default(),
                    &mut tests,
                    ErrorCodes::No,
                    false,
                    None,
                );

                let has_doc_example = tests.found_tests != 0;
                // The `expect_def_id()` should be okay because `local_def_id_to_hir_id`
                // would presumably panic if a fake `DefIndex` were passed.
                let hir_id = self
                    .ctx
                    .tcx
                    .hir()
                    .local_def_id_to_hir_id(i.item_id.expect_def_id().expect_local());
                let (level, source) = self.ctx.tcx.lint_level_at_node(MISSING_DOCS, hir_id);

                // In case we have:
                //
                // ```
                // enum Foo { Bar(u32) }
                // // or:
                // struct Bar(u32);
                // ```
                //
                // there is no need to require documentation on the fields of tuple variants and
                // tuple structs.
                let should_be_ignored = i
                    .item_id
                    .as_def_id()
                    .and_then(|def_id| self.ctx.tcx.opt_parent(def_id))
                    .and_then(|def_id| self.ctx.tcx.hir().get_if_local(def_id))
                    .map(|node| {
                        matches!(
                            node,
                            hir::Node::Variant(hir::Variant {
                                data: hir::VariantData::Tuple(_, _),
                                ..
                            }) | hir::Node::Item(hir::Item {
                                kind: hir::ItemKind::Struct(hir::VariantData::Tuple(_, _), _),
                                ..
                            })
                        )
                    })
                    .unwrap_or(false);

                // `missing_docs` is allow-by-default, so don't treat this as ignoring the item
                // unless the user had an explicit `allow`.
                //
                let should_have_docs = !should_be_ignored
                    && (level != lint::Level::Allow || matches!(source, LintLevelSource::Default));

                if let Some(span) = i.span(self.ctx.tcx) {
                    let filename = span.filename(self.ctx.sess());
                    debug!("counting {:?} {:?} in {:?}", i.type_(), i.name, filename);
                    self.items.entry(filename).or_default().count_item(
                        has_docs,
                        has_doc_example,
                        should_have_doc_example(self.ctx, i),
                        should_have_docs,
                    );
                }
            }
        }

        self.visit_item_recur(i)
    }
}