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
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593

mod input;

use std::collections::HashMap;

use crate::dom::comment::Comment;
use crate::dom::tag::Tag;
use crate::dom::text::Text;
use crate::dom::Dom;
use crate::dom::DomType;
use input::Input;

/// Parses the tag document and returns a Dom structure tree.
///
/// # Arguments
/// * `doc` - tag document
///
/// # Errors
/// * If the document ends in the middle of a tag or double quote.
///
/// # Examples
/// ```rust
/// let html = r#"
/// <body>
///   <h1 class="h1">Hello</h1>
/// </body>
/// }"#;
///
/// if let Ok(dom) = parsercher::parse(&html) {
///     println!("{:#?}", dom);
/// }
/// ```
///
/// output:
///
/// ```text
/// Dom {
///     dom_type: Tag,
///     tag: Some(
///         Tag {
///             name: "root",
///             attr: None,
///             terminated: false,
///             terminator: false,
///         },
///     ),
///     text: None,
///     comment: None,
///     children: Some(
///         [
///             Dom {
///                 dom_type: Tag,
///                 tag: Some(
///                     Tag {
///                         name: "body",
///                         attr: None,
///                         terminated: false,
///                         terminator: false,
///                     },
///                 ),
///                 text: None,
///                 comment: None,
///                 children: Some(
///                     [
///                         Dom {
///                             dom_type: Tag,
///                             tag: Some(
///                                 Tag {
///                                     name: "h1",
///                                     attr: Some(
///                                         {
///                                             "class": "h1",
///                                         },
///                                     ),
///                                     terminated: false,
///                                     terminator: false,
///                                 },
///                             ),
///                             text: None,
///                             comment: None,
///                             children: Some(
///                                 [
///                                     Dom {
///                                         dom_type: Text,
///                                         tag: None,
///                                         text: Some(
///                                             Text {
///                                                 text: "Hello",
///                                             },
///                                         ),
///                                         comment: None,
///                                         children: None,
///                                     },
///                                 ],
///                             ),
///                         },
///                     ],
///                 ),
///             },
///         ],
///     ),
/// }
/// ```
///
pub fn parse(doc: &str) -> Result<Dom, String> {
    let mut input = Input::new(doc);
    let mut dom_vec = create_dom_vec(&mut input)?;
    //debug_print_dom_vec(&dom_vec);

    let mut root_dom = Dom::new_root();
    create_dom_tree(&mut dom_vec, &mut root_dom);
    Ok(root_dom)
}

/// Returns the value of the tag's attribute.
///
/// State to receive:
/// The cursor points to the first '"'.
/// "<value>"
fn parse_tag_attr_value(input: &mut Input) -> Result<String, String> {
    input.next(); // move cursor to after '"'
    let value_bgn = input.get_cursor();

    let value_end;
    match input.find('"') {
        Some(cursor) => value_end = cursor,
        None => return Err(String::from("Input ends in the middle of double quote")),
    }

    if value_bgn == value_end {
        // value is empty
        return Ok(String::new());
    }

    input.set_cursor(value_end);
    input.get_string(value_bgn, value_end)
}

/// Parse tag attributes.
///
/// State to receive:
/// The cursor points to the first character of <attr>.
/// <attr>[ = "<value>"] [/]>
fn parse_tag_attr(input: &mut Input, mut tag: Tag) -> Result<Tag, String> {
    // get the end position of the tag
    let tag_end;
    match input.find('>') {
        Some(cursor) => tag_end = cursor,
        None => return Err(String::from("Input ends in the middle of the tag")),
    }

    let mut attr_map = HashMap::new();

    // get attributes and their value
    // The terminal '/' is also an attribute
    loop {
        if input.expect('>') {
            input.next();
            break;
        }

        let attr_bgn = input.get_cursor();
        let mut attr_end = tag_end;

        // If the tag contains '=', that position is the end position of the attribute name
        if let Some(cursor) = input.find('=') {
            if cursor < tag_end {
                attr_end = cursor;
            }
        }

        // If the tag contains an ' ' and it precedes '=',
        // make that position the end position of the attribute name.
        if let Some(cursor) = input.find(' ') {
            if cursor < attr_end {
                attr_end = cursor;
            }
        }

        input.set_cursor(attr_end);
        let attr_name = input.get_string(attr_bgn, attr_end)?;

        // get value
        let mut value = String::new();
        if input.get_cursor() != tag_end {
            // If the tag contains an '='
            if let Some(cursor) = input.find('=') {
                if cursor < tag_end {
                    input.set_cursor(cursor); // move cursor to '='
                    input.next_char(); // move cursor to after '='
                    if input.expect('"') {
                        match parse_tag_attr_value(input) {
                            Ok(v) => value = v,
                            Err(e) => return Err(e),
                        }
                    }
                }
            }
        }

        attr_map.insert(attr_name, value);

        if input.expect('>') {
            input.next();
            break;
        }

        input.next_char();
    }

    // If the attribute contains '/', remove it
    if let Some(_) = attr_map.remove("/") {
        tag.set_terminated(true);
    }

    tag.set_attrs(attr_map);

    Ok(tag)
}

/// Parse the tag name.
///
/// State to receive:
/// The cursor points to the first character of <tag_name>.
/// <tag_name> [<attr>[="<value>"]] [/]>
fn parse_tag_name(input: &mut Input, terminator: bool) -> Result<Tag, String> {
    // Get the start position of the tag name
    let name_bgn = input.get_cursor();

    // get the end position of the tag
    let tag_end;
    match input.find('>') {
        Some(cursor) => tag_end = cursor,
        None => return Err(String::from("Input ends in the middle of the tag")),
    }

    let mut name_end = tag_end;

    // If the tag contains ' ', make that position the end position of the tag name.
    if let Some(cursor) = input.find(' ') {
        if cursor < tag_end {
            name_end = cursor;
        }
    }

    input.set_cursor(name_end);
    let mut tag = Tag::new(&input.get_string(name_bgn, name_end)?);
    tag.set_terminator(terminator);

    if input.expect('>') {
        input.next(); // move cursor to after '>'
        return Ok(tag);
    }

    input.next_char();

    // If there are spaces before the '>'
    if input.expect('>') {
        input.next();
        return Ok(tag);
    }

    return parse_tag_attr(input, tag);
}

/// Parses the tag and returns a Dom structure.
///
/// State to receive:
/// The cursor points to the first '<'.
/// <[/]<tag_name> [<attr>[="<value>"]] [/]>
fn parse_tag(input: &mut Input) -> Result<Dom, String> {
    input.next(); // move cursor to after '<'

    let mut terminator = false;
    if input.expect('/') {
        input.next(); // move cursor to after '/'
        terminator = true;
    }

    let tag = parse_tag_name(input, terminator)?;
    // TODO debug
    //println!("{:#?}", tag);
    let mut dom = Dom::new(DomType::Tag);
    dom.set_tag(tag);
    return Ok(dom);
}

/// Parse comment.
///
/// State to receive:
/// The cursor points to the first '<'.
/// <!-- <comment> -->
fn parse_comment(input: &mut Input) -> Result<Dom, String> {
    // get the position after "<!--"
    let bgn = input.get_cursor() + "<!--".len();

    match input.find_str("-->") {
        Some(cursor) => {
            input.set_cursor(cursor + "-->".len()); // move cursor after "-->"
            let comment = Comment::new(&input.get_string(bgn, cursor)?);
            // TODO debug
            //println!("{:#?}", comment);
            let mut dom = Dom::new(DomType::Comment);
            dom.set_comment(comment);
            return Ok(dom);
        }
        None => return Err(String::from("Input ends in the middle of the comment")),
    }
}

/// Tet text.
fn parse_text(input: &mut Input) -> Result<Dom, String> {
    let bgn = input.get_cursor();

    let end;
    match input.find('<') {
        Some(cursor) => {
            input.set_cursor(cursor);
            end = cursor;
        }
        None => {
            input.next_char();
            end = input.get_cursor();
        }
    }

    let text = Text::new(&input.get_string(bgn, end)?);
    // TODO debug
    //println!("{:#?}", text);
    let mut dom = Dom::new(DomType::Text);
    dom.set_text(text);
    return Ok(dom);
}

/// Get the code of the script tag as text.
fn parse_text_script(input: &mut Input) -> Result<Dom, String> {
    let bgn = input.get_cursor();
    let end;

    match input.find_str("</script") {
        Some(cursor) => {
            input.set_cursor(cursor);
            end = cursor;
        }
        None => return Err(String::from("Input ends in the middle of the tag")),
    }

    let text = Text::new(&input.get_string(bgn, end)?);
    let mut dom = Dom::new(DomType::Text);
    dom.set_text(text);
    return Ok(dom);
}

/// Parse "<!doctype html>".
/// case insensitive.
///
/// State to receive:
/// The cursor points to the first '<'.
/// <!doctype html>
#[allow(dead_code)]
fn parse_doctype(input: &mut Input) -> Result<Dom, String> {
    if !input.expect_str_insensitive("<!doctype html>") {
        return Err(String::from("Input is not html"));
    }

    // Set the tag name to "doctype"
    input.next(); // move cursor to '!'
    input.next(); // move cursor to 'd'
    let bgn = input.get_cursor();
    let end = bgn + "doctype".len();
    input.set_cursor(end); // move cursor to the ' ' before the "html"
    let mut tag = Tag::new(&input.get_string(bgn, end)?);

    input.next(); // move cursor to 'h'

    // Set the attribute to "html"
    // The value of attribute is ""
    let mut attr: HashMap<String, String> = HashMap::new();
    let bgn = input.get_cursor();
    let end = bgn + "html".len();
    input.set_cursor(end); // move cursor to '>'
    attr.insert(input.get_string(bgn, end)?, String::new());
    tag.set_attrs(attr);

    let mut dom = Dom::new(DomType::Tag);
    dom.set_tag(tag);

    input.next(); // move cursor to after '>'

    Ok(dom)
}

/// Parses the tag document and returns the Vec of the Dom structure.
fn create_dom_vec(input: &mut Input) -> Result<Vec<Dom>, String> {
    let mut dom_vec: Vec<Dom> = Vec::new();

    // move cursor to the first '<'
    while !input.expect('<') {
        input.next_char();
    }

    /*
    // "<!doctype html>"
    match parse_doctype(input) {
        Ok(dom) => dom_vec.push(dom),
        Err(e) => return Err(e),
    }
    */

    while !input.is_end() {
        // TODO debug
        //println!("check: {}", input.get_char(input.get_cursor())?);
        if input.expect_str("<!--") {
            // comment
            match parse_comment(input) {
                Ok(dom) => dom_vec.push(dom),
                Err(e) => return Err(e),
            }
        } else if input.expect('<') {
            // tag
            match parse_tag(input) {
                Ok(dom) => {
                    // if the dom is script tag
                    let mut is_bgn_script = false;
                    if let DomType::Tag = dom.dom_type {
                        let tag = dom.get_tag().unwrap();
                        if tag.get_name() == "script" && !tag.is_terminator() {
                            is_bgn_script = true;
                        }
                    }

                    dom_vec.push(dom);

                    // if the dom is script tag and has text
                    if is_bgn_script && !input.expect('<') {
                        match parse_text_script(input) {
                            Ok(dom) => dom_vec.push(dom),
                            Err(e) => return Err(e),
                        }
                    }
                }
                Err(e) => return Err(e),
            }
        } else {
            if input.expect(' ') || input.expect('\n') {
                input.next_char(); // skip ' ' and '\n'
            }

            if !input.expect('<') {
                // text
                match parse_text(input) {
                    Ok(dom) => dom_vec.push(dom),
                    Err(e) => return Err(e),
                }
            }
        }
    }
    Ok(dom_vec)
}

/// dom_vec debugging function
#[allow(dead_code)]
fn debug_print_dom_vec(dom_vec: &Vec<Dom>) {
    for dom in dom_vec.iter() {
        match dom.dom_type {
            DomType::Tag => println!("{:#?}", dom.get_tag().unwrap()),
            DomType::Text => println!("{:#?}", dom.get_text().unwrap()),
            DomType::Comment => println!("{:#?}", dom.get_comment().unwrap()),
        }
    }
}

/// Find the end tag paired with `starter` from dom_vec and return its index.
fn search_terminator(dom_vec: &mut Vec<Dom>, starter: &Tag) -> Option<usize> {
    let mut i = 0;
    while i < dom_vec.len() {
        let dom = dom_vec.get(i).unwrap();
        if let DomType::Tag = dom.dom_type {
            let tag = dom.get_tag().unwrap();
            if tag.is_terminator() {
                if starter.get_name() == tag.get_name() {
                    return Some(i);
                }
            }
        }
        i += 1;
    }
    None
}

/// If the tag is not terminated, add it to the child, otherwise add it to the child.
fn create_dom_tree(dom_vec: &mut Vec<Dom>, parent: &mut Dom) {
    while !dom_vec.is_empty() {
        let mut dom = dom_vec.remove(0);

        if let DomType::Tag = dom.dom_type {
            let tag = dom.get_tag().unwrap();

            if tag.is_terminator() {
                // If tag is terminator. `</ tag>`
                return;
            }

            if !tag.is_terminated() {
                // If not self-terminating. not `<tag />`
                if let Some(terminator_idx) = search_terminator(dom_vec, tag) {
                    // If there is terminator tag
                    if terminator_idx == 0 {
                        // If there are no children, delete the terminator tag
                        dom_vec.remove(0);
                    } else {
                        // If there are children, recurse
                        create_dom_tree(dom_vec, &mut dom);
                    }
                }
            }
        }

        parent.add_child(dom);
    }
}

/// Output the Dom structure in a human readable format.
///
/// Using `println!`.
/// Useful for debugging.
///
/// # Examples
/// Output the following HTML.
/// ```rust
/// let html = r#"
/// <head>
///   <meta charset="UTF-8">
///   <title>sample</title>
/// </head>
/// <body>
///   <h1>Hello, world!</h1>
/// </body>
/// "#;
/// if let Ok(dom) = parsercher::parse(&html) {
///     parsercher::print_dom_tree(&dom);
/// }
/// ```
/// output:
/// ```text
/// <root>
///   <head>
///     <meta charset="UTF-8">
///     <title>
///       TEXT: "sample"
///   <body>
///     <h1>
///       TEXT: "Hello, world!"
/// ```
pub fn print_dom_tree(dom: &Dom) {
    print_dom_tree_exe(dom, 0);
}

fn print_dom_tree_exe(dom: &Dom, depth: usize) {
    for _ in 0..depth {
        print!("  ");
    }

    match dom.dom_type {
        DomType::Tag => {
            let tag = dom.get_tag().unwrap();
            print!("<{}", tag.get_name());
            if let Some(attrs) = tag.get_attrs() {
                for (attr, value) in attrs.iter() {
                    print!(" {}=\"{}\"", attr, value);
                }
            }
            println!(">");

            if let Some(children) = dom.get_children() {
                for child in children {
                    print_dom_tree_exe(child, depth + 1);
                }
            }
        }
        DomType::Text => {
            let text = dom.get_text().unwrap();
            let text = String::from(text.get_text());
            let text = text.replace("\n", "\\n");
            println!("TEXT: \"{}\"", text);
        }
        DomType::Comment => {
            let comment = dom.get_comment().unwrap();
            let comment = String::from(comment.get_comment());
            let comment = comment.replace("\n", "\\n");
            println!("<!--\"{}\"-->", comment);
        }
    }
}