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
#[cfg(not(feature = "std"))]
use alloc::{string::String, vec::Vec};
use core::mem;

use crate::{
    Align, Attrs, AttrsList, Cached, FontSystem, LayoutLine, LineEnding, ShapeLine, Shaping, Wrap,
};

/// A line (or paragraph) of text that is shaped and laid out
#[derive(Clone, Debug)]
pub struct BufferLine {
    text: String,
    ending: LineEnding,
    attrs_list: AttrsList,
    align: Option<Align>,
    shape_opt: Cached<ShapeLine>,
    layout_opt: Cached<Vec<LayoutLine>>,
    shaping: Shaping,
    metadata: Option<usize>,
}

impl BufferLine {
    /// Create a new line with the given text and attributes list
    /// Cached shaping and layout can be done using the [`Self::shape`] and
    /// [`Self::layout`] functions
    pub fn new<T: Into<String>>(
        text: T,
        ending: LineEnding,
        attrs_list: AttrsList,
        shaping: Shaping,
    ) -> Self {
        Self {
            text: text.into(),
            ending,
            attrs_list,
            align: None,
            shape_opt: Cached::Empty,
            layout_opt: Cached::Empty,
            shaping,
            metadata: None,
        }
    }

    /// Resets the current line with new internal values.
    ///
    /// Avoids deallocating internal caches so they can be reused.
    pub fn reset_new<T: Into<String>>(
        &mut self,
        text: T,
        ending: LineEnding,
        attrs_list: AttrsList,
        shaping: Shaping,
    ) {
        self.text = text.into();
        self.ending = ending;
        self.attrs_list = attrs_list;
        self.align = None;
        self.shape_opt.set_unused();
        self.layout_opt.set_unused();
        self.shaping = shaping;
        self.metadata = None;
    }

    /// Get current text
    pub fn text(&self) -> &str {
        &self.text
    }

    /// Set text and attributes list
    ///
    /// Will reset shape and layout if it differs from current text and attributes list.
    /// Returns true if the line was reset
    pub fn set_text<T: AsRef<str>>(
        &mut self,
        text: T,
        ending: LineEnding,
        attrs_list: AttrsList,
    ) -> bool {
        let text = text.as_ref();
        if text != self.text || ending != self.ending || attrs_list != self.attrs_list {
            self.text.clear();
            self.text.push_str(text);
            self.ending = ending;
            self.attrs_list = attrs_list;
            self.reset();
            true
        } else {
            false
        }
    }

    /// Consume this line, returning only its text contents as a String.
    pub fn into_text(self) -> String {
        self.text
    }

    /// Get line ending
    pub fn ending(&self) -> LineEnding {
        self.ending
    }

    /// Set line ending
    ///
    /// Will reset shape and layout if it differs from current line ending.
    /// Returns true if the line was reset
    pub fn set_ending(&mut self, ending: LineEnding) -> bool {
        if ending != self.ending {
            self.ending = ending;
            self.reset_shaping();
            true
        } else {
            false
        }
    }

    /// Get attributes list
    pub fn attrs_list(&self) -> &AttrsList {
        &self.attrs_list
    }

    /// Set attributes list
    ///
    /// Will reset shape and layout if it differs from current attributes list.
    /// Returns true if the line was reset
    pub fn set_attrs_list(&mut self, attrs_list: AttrsList) -> bool {
        if attrs_list != self.attrs_list {
            self.attrs_list = attrs_list;
            self.reset_shaping();
            true
        } else {
            false
        }
    }

    /// Get the Text alignment
    pub fn align(&self) -> Option<Align> {
        self.align
    }

    /// Set the text alignment
    ///
    /// Will reset layout if it differs from current alignment.
    /// Setting to None will use `Align::Right` for RTL lines, and `Align::Left` for LTR lines.
    /// Returns true if the line was reset
    pub fn set_align(&mut self, align: Option<Align>) -> bool {
        if align != self.align {
            self.align = align;
            self.reset_layout();
            true
        } else {
            false
        }
    }

    /// Append line at end of this line
    ///
    /// The wrap setting of the appended line will be lost
    pub fn append(&mut self, other: Self) {
        let len = self.text.len();
        self.text.push_str(other.text());

        if other.attrs_list.defaults() != self.attrs_list.defaults() {
            // If default formatting does not match, make a new span for it
            self.attrs_list
                .add_span(len..len + other.text().len(), other.attrs_list.defaults());
        }

        for (other_range, attrs) in other.attrs_list.spans_iter() {
            // Add previous attrs spans
            let range = other_range.start + len..other_range.end + len;
            self.attrs_list.add_span(range, attrs.as_attrs());
        }

        self.reset();
    }

    /// Split off new line at index
    pub fn split_off(&mut self, index: usize) -> Self {
        let text = self.text.split_off(index);
        let attrs_list = self.attrs_list.split_off(index);
        self.reset();

        let mut new = Self::new(text, self.ending, attrs_list, self.shaping);
        new.align = self.align;
        new
    }

    /// Reset shaping, layout, and metadata caches
    pub fn reset(&mut self) {
        self.metadata = None;
        self.reset_shaping();
    }

    /// Reset shaping and layout caches
    pub fn reset_shaping(&mut self) {
        self.shape_opt.set_unused();
        self.reset_layout();
    }

    /// Reset only layout cache
    pub fn reset_layout(&mut self) {
        self.layout_opt.set_unused();
    }

    /// Shape line, will cache results
    pub fn shape(&mut self, font_system: &mut FontSystem, tab_width: u16) -> &ShapeLine {
        if self.shape_opt.is_unused() {
            let mut line = self
                .shape_opt
                .take_unused()
                .unwrap_or_else(ShapeLine::empty);
            line.build(
                font_system,
                &self.text,
                &self.attrs_list,
                self.shaping,
                tab_width,
            );
            self.shape_opt.set_used(line);
            self.layout_opt.set_unused();
        }
        self.shape_opt.get().expect("shape not found")
    }

    /// Get line shaping cache
    pub fn shape_opt(&self) -> Option<&ShapeLine> {
        self.shape_opt.get()
    }

    /// Layout line, will cache results
    pub fn layout(
        &mut self,
        font_system: &mut FontSystem,
        font_size: f32,
        width_opt: Option<f32>,
        wrap: Wrap,
        match_mono_width: Option<f32>,
        tab_width: u16,
    ) -> &[LayoutLine] {
        if self.layout_opt.is_unused() {
            let align = self.align;
            let mut layout = self
                .layout_opt
                .take_unused()
                .unwrap_or_else(|| Vec::with_capacity(1));
            let shape = self.shape(font_system, tab_width);
            shape.layout_to_buffer(
                &mut font_system.shape_buffer,
                font_size,
                width_opt,
                wrap,
                align,
                &mut layout,
                match_mono_width,
            );
            self.layout_opt.set_used(layout);
        }
        self.layout_opt.get().expect("layout not found")
    }

    /// Get line layout cache
    pub fn layout_opt(&self) -> Option<&Vec<LayoutLine>> {
        self.layout_opt.get()
    }

    /// Get line metadata. This will be None if [`BufferLine::set_metadata`] has not been called
    /// after the last reset of shaping and layout caches
    pub fn metadata(&self) -> Option<usize> {
        self.metadata
    }

    /// Set line metadata. This is stored until the next line reset
    pub fn set_metadata(&mut self, metadata: usize) {
        self.metadata = Some(metadata);
    }

    /// Makes an empty buffer line.
    ///
    /// The buffer line is in an invalid state after this is called. See [`Self::reset_new`].
    pub(crate) fn empty() -> Self {
        Self {
            text: String::default(),
            ending: LineEnding::default(),
            attrs_list: AttrsList::new(Attrs::new()),
            align: None,
            shape_opt: Cached::Empty,
            layout_opt: Cached::Empty,
            shaping: Shaping::Advanced,
            metadata: None,
        }
    }

    /// Reclaim attributes list memory that isn't needed any longer.
    ///
    /// The buffer line is in an invalid state after this is called. See [`Self::reset_new`].
    pub(crate) fn reclaim_attrs(&mut self) -> AttrsList {
        mem::replace(&mut self.attrs_list, AttrsList::new(Attrs::new()))
    }

    /// Reclaim text memory that isn't needed any longer.
    ///
    /// The buffer line is in an invalid state after this is called. See [`Self::reset_new`].
    pub(crate) fn reclaim_text(&mut self) -> String {
        let mut text = mem::take(&mut self.text);
        text.clear();
        text
    }
}