pane.rs

  1use super::{ItemHandle, SplitDirection};
  2use crate::{toolbar::Toolbar, Item, WeakItemHandle, Workspace};
  3use anyhow::Result;
  4use collections::{HashMap, VecDeque};
  5use futures::StreamExt;
  6use gpui::{
  7    actions,
  8    elements::*,
  9    geometry::{rect::RectF, vector::vec2f},
 10    impl_actions, impl_internal_actions,
 11    platform::{CursorStyle, NavigationDirection},
 12    AppContext, AsyncAppContext, Entity, ModelHandle, MutableAppContext, PromptLevel, Quad,
 13    RenderContext, Task, View, ViewContext, ViewHandle, WeakViewHandle,
 14};
 15use project::{Project, ProjectEntryId, ProjectPath};
 16use serde::Deserialize;
 17use settings::Settings;
 18use std::{any::Any, cell::RefCell, cmp, mem, path::Path, rc::Rc};
 19use util::ResultExt;
 20
 21actions!(
 22    pane,
 23    [
 24        ActivatePrevItem,
 25        ActivateNextItem,
 26        CloseActiveItem,
 27        CloseInactiveItems,
 28    ]
 29);
 30
 31#[derive(Clone, Deserialize)]
 32pub struct Split(pub SplitDirection);
 33
 34#[derive(Clone)]
 35pub struct CloseItem {
 36    pub item_id: usize,
 37    pub pane: WeakViewHandle<Pane>,
 38}
 39
 40#[derive(Clone, Deserialize)]
 41pub struct ActivateItem(pub usize);
 42
 43#[derive(Clone, Deserialize)]
 44pub struct GoBack {
 45    #[serde(skip_deserializing)]
 46    pub pane: Option<WeakViewHandle<Pane>>,
 47}
 48
 49#[derive(Clone, Deserialize)]
 50pub struct GoForward {
 51    #[serde(skip_deserializing)]
 52    pub pane: Option<WeakViewHandle<Pane>>,
 53}
 54
 55impl_actions!(pane, [Split, GoBack, GoForward]);
 56impl_internal_actions!(pane, [CloseItem, ActivateItem]);
 57
 58const MAX_NAVIGATION_HISTORY_LEN: usize = 1024;
 59
 60pub fn init(cx: &mut MutableAppContext) {
 61    cx.add_action(|pane: &mut Pane, action: &ActivateItem, cx| {
 62        pane.activate_item(action.0, true, true, cx);
 63    });
 64    cx.add_action(|pane: &mut Pane, _: &ActivatePrevItem, cx| {
 65        pane.activate_prev_item(cx);
 66    });
 67    cx.add_action(|pane: &mut Pane, _: &ActivateNextItem, cx| {
 68        pane.activate_next_item(cx);
 69    });
 70    cx.add_async_action(Pane::close_active_item);
 71    cx.add_async_action(Pane::close_inactive_items);
 72    cx.add_async_action(|workspace: &mut Workspace, action: &CloseItem, cx| {
 73        let pane = action.pane.upgrade(cx)?;
 74        let task = Pane::close_item(workspace, pane, action.item_id, cx);
 75        Some(cx.foreground().spawn(async move {
 76            task.await?;
 77            Ok(())
 78        }))
 79    });
 80    cx.add_action(|pane: &mut Pane, action: &Split, cx| {
 81        pane.split(action.0, cx);
 82    });
 83    cx.add_action(|workspace: &mut Workspace, action: &GoBack, cx| {
 84        Pane::go_back(
 85            workspace,
 86            action
 87                .pane
 88                .as_ref()
 89                .and_then(|weak_handle| weak_handle.upgrade(cx)),
 90            cx,
 91        )
 92        .detach();
 93    });
 94    cx.add_action(|workspace: &mut Workspace, action: &GoForward, cx| {
 95        Pane::go_forward(
 96            workspace,
 97            action
 98                .pane
 99                .as_ref()
100                .and_then(|weak_handle| weak_handle.upgrade(cx)),
101            cx,
102        )
103        .detach();
104    });
105}
106
107pub enum Event {
108    Activate,
109    ActivateItem { local: bool },
110    Remove,
111    Split(SplitDirection),
112}
113
114pub struct Pane {
115    items: Vec<Box<dyn ItemHandle>>,
116    active_item_index: usize,
117    autoscroll: bool,
118    nav_history: Rc<RefCell<NavHistory>>,
119    toolbar: ViewHandle<Toolbar>,
120}
121
122pub struct ItemNavHistory {
123    history: Rc<RefCell<NavHistory>>,
124    item: Rc<dyn WeakItemHandle>,
125}
126
127#[derive(Default)]
128pub struct NavHistory {
129    mode: NavigationMode,
130    backward_stack: VecDeque<NavigationEntry>,
131    forward_stack: VecDeque<NavigationEntry>,
132    paths_by_item: HashMap<usize, ProjectPath>,
133}
134
135#[derive(Copy, Clone)]
136enum NavigationMode {
137    Normal,
138    GoingBack,
139    GoingForward,
140    Disabled,
141}
142
143impl Default for NavigationMode {
144    fn default() -> Self {
145        Self::Normal
146    }
147}
148
149pub struct NavigationEntry {
150    pub item: Rc<dyn WeakItemHandle>,
151    pub data: Option<Box<dyn Any>>,
152}
153
154impl Pane {
155    pub fn new(cx: &mut ViewContext<Self>) -> Self {
156        Self {
157            items: Vec::new(),
158            active_item_index: 0,
159            autoscroll: false,
160            nav_history: Default::default(),
161            toolbar: cx.add_view(|_| Toolbar::new()),
162        }
163    }
164
165    pub fn nav_history(&self) -> &Rc<RefCell<NavHistory>> {
166        &self.nav_history
167    }
168
169    pub fn activate(&self, cx: &mut ViewContext<Self>) {
170        cx.emit(Event::Activate);
171    }
172
173    pub fn go_back(
174        workspace: &mut Workspace,
175        pane: Option<ViewHandle<Pane>>,
176        cx: &mut ViewContext<Workspace>,
177    ) -> Task<()> {
178        Self::navigate_history(
179            workspace,
180            pane.unwrap_or_else(|| workspace.active_pane().clone()),
181            NavigationMode::GoingBack,
182            cx,
183        )
184    }
185
186    pub fn go_forward(
187        workspace: &mut Workspace,
188        pane: Option<ViewHandle<Pane>>,
189        cx: &mut ViewContext<Workspace>,
190    ) -> Task<()> {
191        Self::navigate_history(
192            workspace,
193            pane.unwrap_or_else(|| workspace.active_pane().clone()),
194            NavigationMode::GoingForward,
195            cx,
196        )
197    }
198
199    fn navigate_history(
200        workspace: &mut Workspace,
201        pane: ViewHandle<Pane>,
202        mode: NavigationMode,
203        cx: &mut ViewContext<Workspace>,
204    ) -> Task<()> {
205        workspace.activate_pane(pane.clone(), cx);
206
207        let to_load = pane.update(cx, |pane, cx| {
208            loop {
209                // Retrieve the weak item handle from the history.
210                let entry = pane.nav_history.borrow_mut().pop(mode)?;
211
212                // If the item is still present in this pane, then activate it.
213                if let Some(index) = entry
214                    .item
215                    .upgrade(cx)
216                    .and_then(|v| pane.index_for_item(v.as_ref()))
217                {
218                    let prev_active_item_index = pane.active_item_index;
219                    pane.nav_history.borrow_mut().set_mode(mode);
220                    pane.activate_item(index, true, true, cx);
221                    pane.nav_history
222                        .borrow_mut()
223                        .set_mode(NavigationMode::Normal);
224
225                    let mut navigated = prev_active_item_index != pane.active_item_index;
226                    if let Some(data) = entry.data {
227                        navigated |= pane.active_item()?.navigate(data, cx);
228                    }
229
230                    if navigated {
231                        break None;
232                    }
233                }
234                // If the item is no longer present in this pane, then retrieve its
235                // project path in order to reopen it.
236                else {
237                    break pane
238                        .nav_history
239                        .borrow_mut()
240                        .paths_by_item
241                        .get(&entry.item.id())
242                        .cloned()
243                        .map(|project_path| (project_path, entry));
244                }
245            }
246        });
247
248        if let Some((project_path, entry)) = to_load {
249            // If the item was no longer present, then load it again from its previous path.
250            let pane = pane.downgrade();
251            let task = workspace.load_path(project_path, cx);
252            cx.spawn(|workspace, mut cx| async move {
253                let task = task.await;
254                if let Some(pane) = pane.upgrade(&cx) {
255                    if let Some((project_entry_id, build_item)) = task.log_err() {
256                        pane.update(&mut cx, |pane, _| {
257                            pane.nav_history.borrow_mut().set_mode(mode);
258                        });
259                        let item = workspace.update(&mut cx, |workspace, cx| {
260                            Self::open_item(
261                                workspace,
262                                pane.clone(),
263                                project_entry_id,
264                                true,
265                                cx,
266                                build_item,
267                            )
268                        });
269                        pane.update(&mut cx, |pane, cx| {
270                            pane.nav_history
271                                .borrow_mut()
272                                .set_mode(NavigationMode::Normal);
273                            if let Some(data) = entry.data {
274                                item.navigate(data, cx);
275                            }
276                        });
277                    } else {
278                        workspace
279                            .update(&mut cx, |workspace, cx| {
280                                Self::navigate_history(workspace, pane, mode, cx)
281                            })
282                            .await;
283                    }
284                }
285            })
286        } else {
287            Task::ready(())
288        }
289    }
290
291    pub(crate) fn open_item(
292        workspace: &mut Workspace,
293        pane: ViewHandle<Pane>,
294        project_entry_id: ProjectEntryId,
295        focus_item: bool,
296        cx: &mut ViewContext<Workspace>,
297        build_item: impl FnOnce(&mut MutableAppContext) -> Box<dyn ItemHandle>,
298    ) -> Box<dyn ItemHandle> {
299        let existing_item = pane.update(cx, |pane, cx| {
300            for (ix, item) in pane.items.iter().enumerate() {
301                if item.project_entry_ids(cx).as_slice() == &[project_entry_id] {
302                    let item = item.boxed_clone();
303                    pane.activate_item(ix, true, focus_item, cx);
304                    return Some(item);
305                }
306            }
307            None
308        });
309        if let Some(existing_item) = existing_item {
310            existing_item
311        } else {
312            let item = build_item(cx);
313            Self::add_item(workspace, pane, item.boxed_clone(), true, focus_item, cx);
314            item
315        }
316    }
317
318    pub(crate) fn add_item(
319        workspace: &mut Workspace,
320        pane: ViewHandle<Pane>,
321        item: Box<dyn ItemHandle>,
322        activate_pane: bool,
323        focus_item: bool,
324        cx: &mut ViewContext<Workspace>,
325    ) {
326        // Prevent adding the same item to the pane more than once.
327        if let Some(item_ix) = pane.read(cx).items.iter().position(|i| i.id() == item.id()) {
328            pane.update(cx, |pane, cx| {
329                pane.activate_item(item_ix, activate_pane, focus_item, cx)
330            });
331            return;
332        }
333
334        item.set_nav_history(pane.read(cx).nav_history.clone(), cx);
335        item.added_to_pane(workspace, pane.clone(), cx);
336        pane.update(cx, |pane, cx| {
337            let item_idx = cmp::min(pane.active_item_index + 1, pane.items.len());
338            pane.items.insert(item_idx, item);
339            pane.activate_item(item_idx, activate_pane, focus_item, cx);
340            cx.notify();
341        });
342    }
343
344    pub fn items(&self) -> impl Iterator<Item = &Box<dyn ItemHandle>> {
345        self.items.iter()
346    }
347
348    pub fn items_of_type<'a, T: View>(&'a self) -> impl 'a + Iterator<Item = ViewHandle<T>> {
349        self.items
350            .iter()
351            .filter_map(|item| item.to_any().downcast())
352    }
353
354    pub fn active_item(&self) -> Option<Box<dyn ItemHandle>> {
355        self.items.get(self.active_item_index).cloned()
356    }
357
358    pub fn item_for_entry(
359        &self,
360        entry_id: ProjectEntryId,
361        cx: &AppContext,
362    ) -> Option<Box<dyn ItemHandle>> {
363        self.items.iter().find_map(|item| {
364            if item.project_entry_ids(cx).as_slice() == &[entry_id] {
365                Some(item.boxed_clone())
366            } else {
367                None
368            }
369        })
370    }
371
372    pub fn index_for_item(&self, item: &dyn ItemHandle) -> Option<usize> {
373        self.items.iter().position(|i| i.id() == item.id())
374    }
375
376    pub fn activate_item(
377        &mut self,
378        index: usize,
379        activate_pane: bool,
380        focus_item: bool,
381        cx: &mut ViewContext<Self>,
382    ) {
383        use NavigationMode::{GoingBack, GoingForward};
384        if index < self.items.len() {
385            let prev_active_item_ix = mem::replace(&mut self.active_item_index, index);
386            if matches!(self.nav_history.borrow().mode, GoingBack | GoingForward)
387                || (prev_active_item_ix != self.active_item_index
388                    && prev_active_item_ix < self.items.len())
389            {
390                self.items[prev_active_item_ix].deactivated(cx);
391                cx.emit(Event::ActivateItem {
392                    local: activate_pane,
393                });
394            }
395            self.update_toolbar(cx);
396            if focus_item {
397                self.focus_active_item(cx);
398            }
399            if activate_pane {
400                self.activate(cx);
401            }
402            self.autoscroll = true;
403            cx.notify();
404        }
405    }
406
407    pub fn activate_prev_item(&mut self, cx: &mut ViewContext<Self>) {
408        let mut index = self.active_item_index;
409        if index > 0 {
410            index -= 1;
411        } else if self.items.len() > 0 {
412            index = self.items.len() - 1;
413        }
414        self.activate_item(index, true, true, cx);
415    }
416
417    pub fn activate_next_item(&mut self, cx: &mut ViewContext<Self>) {
418        let mut index = self.active_item_index;
419        if index + 1 < self.items.len() {
420            index += 1;
421        } else {
422            index = 0;
423        }
424        self.activate_item(index, true, true, cx);
425    }
426
427    fn close_active_item(
428        workspace: &mut Workspace,
429        _: &CloseActiveItem,
430        cx: &mut ViewContext<Workspace>,
431    ) -> Option<Task<Result<()>>> {
432        let pane_handle = workspace.active_pane().clone();
433        let pane = pane_handle.read(cx);
434        if pane.items.is_empty() {
435            None
436        } else {
437            let item_id_to_close = pane.items[pane.active_item_index].id();
438            let task = Self::close_items(workspace, pane_handle, cx, move |item_id| {
439                item_id == item_id_to_close
440            });
441            Some(cx.foreground().spawn(async move {
442                task.await?;
443                Ok(())
444            }))
445        }
446    }
447
448    pub fn close_inactive_items(
449        workspace: &mut Workspace,
450        _: &CloseInactiveItems,
451        cx: &mut ViewContext<Workspace>,
452    ) -> Option<Task<Result<()>>> {
453        let pane_handle = workspace.active_pane().clone();
454        let pane = pane_handle.read(cx);
455        if pane.items.is_empty() {
456            None
457        } else {
458            let active_item_id = pane.items[pane.active_item_index].id();
459            let task =
460                Self::close_items(workspace, pane_handle, cx, move |id| id != active_item_id);
461            Some(cx.foreground().spawn(async move {
462                task.await?;
463                Ok(())
464            }))
465        }
466    }
467
468    pub fn close_item(
469        workspace: &mut Workspace,
470        pane: ViewHandle<Pane>,
471        item_id_to_close: usize,
472        cx: &mut ViewContext<Workspace>,
473    ) -> Task<Result<bool>> {
474        Self::close_items(workspace, pane, cx, move |view_id| {
475            view_id == item_id_to_close
476        })
477    }
478
479    pub fn close_items(
480        workspace: &mut Workspace,
481        pane: ViewHandle<Pane>,
482        cx: &mut ViewContext<Workspace>,
483        should_close: impl 'static + Fn(usize) -> bool,
484    ) -> Task<Result<bool>> {
485        let project = workspace.project().clone();
486
487        // Find which items to close.
488        let mut items_to_close = Vec::new();
489        for item in &pane.read(cx).items {
490            if should_close(item.id()) {
491                items_to_close.push(item.boxed_clone());
492            }
493        }
494
495        cx.spawn(|workspace, mut cx| async move {
496            for item in items_to_close.clone() {
497                let (item_ix, project_entry_ids) = pane.read_with(&cx, |pane, cx| {
498                    (
499                        pane.index_for_item(item.as_ref()),
500                        item.project_entry_ids(cx),
501                    )
502                });
503
504                let item_ix = if let Some(ix) = item_ix {
505                    ix
506                } else {
507                    continue;
508                };
509
510                // An item should be saved if either it has *no* project entries, or if it
511                // has project entries that don't exist anywhere else in the workspace.
512                let mut should_save = project_entry_ids.is_empty();
513                let mut project_entry_ids_to_save = project_entry_ids;
514                workspace.read_with(&cx, |workspace, cx| {
515                    for item in workspace.items(cx) {
516                        if !items_to_close
517                            .iter()
518                            .any(|item_to_close| item_to_close.id() == item.id())
519                        {
520                            let project_entry_ids = item.project_entry_ids(cx);
521                            project_entry_ids_to_save.retain(|id| !project_entry_ids.contains(&id));
522                        }
523                    }
524                });
525                if !project_entry_ids_to_save.is_empty() {
526                    should_save = true;
527                }
528
529                if should_save
530                    && !Self::save_item(project.clone(), &pane, item_ix, &item, true, &mut cx)
531                        .await?
532                {
533                    break;
534                }
535
536                pane.update(&mut cx, |pane, cx| {
537                    if let Some(item_ix) = pane.items.iter().position(|i| i.id() == item.id()) {
538                        if item_ix == pane.active_item_index {
539                            if item_ix + 1 < pane.items.len() {
540                                pane.activate_next_item(cx);
541                            } else if item_ix > 0 {
542                                pane.activate_prev_item(cx);
543                            }
544                        }
545
546                        let item = pane.items.remove(item_ix);
547                        if pane.items.is_empty() {
548                            item.deactivated(cx);
549                            pane.update_toolbar(cx);
550                            cx.emit(Event::Remove);
551                        }
552
553                        if item_ix < pane.active_item_index {
554                            pane.active_item_index -= 1;
555                        }
556
557                        let mut nav_history = pane.nav_history.borrow_mut();
558                        if let Some(path) = item.project_path(cx) {
559                            nav_history.paths_by_item.insert(item.id(), path);
560                        } else {
561                            nav_history.paths_by_item.remove(&item.id());
562                        }
563                    }
564                });
565            }
566
567            pane.update(&mut cx, |_, cx| cx.notify());
568            Ok(true)
569        })
570    }
571
572    pub async fn save_item(
573        project: ModelHandle<Project>,
574        pane: &ViewHandle<Pane>,
575        item_ix: usize,
576        item: &Box<dyn ItemHandle>,
577        should_prompt_for_save: bool,
578        cx: &mut AsyncAppContext,
579    ) -> Result<bool> {
580        const CONFLICT_MESSAGE: &'static str =
581            "This file has changed on disk since you started editing it. Do you want to overwrite it?";
582        const DIRTY_MESSAGE: &'static str =
583            "This file contains unsaved edits. Do you want to save it?";
584
585        let (has_conflict, is_dirty, can_save, can_save_as) = cx.read(|cx| {
586            (
587                item.has_conflict(cx),
588                item.is_dirty(cx),
589                item.can_save(cx),
590                item.can_save_as(cx),
591            )
592        });
593
594        if has_conflict && can_save {
595            let mut answer = pane.update(cx, |pane, cx| {
596                pane.activate_item(item_ix, true, true, cx);
597                cx.prompt(
598                    PromptLevel::Warning,
599                    CONFLICT_MESSAGE,
600                    &["Overwrite", "Discard", "Cancel"],
601                )
602            });
603            match answer.next().await {
604                Some(0) => cx.update(|cx| item.save(project, cx)).await?,
605                Some(1) => cx.update(|cx| item.reload(project, cx)).await?,
606                _ => return Ok(false),
607            }
608        } else if is_dirty && (can_save || can_save_as) {
609            let should_save = if should_prompt_for_save {
610                let mut answer = pane.update(cx, |pane, cx| {
611                    pane.activate_item(item_ix, true, true, cx);
612                    cx.prompt(
613                        PromptLevel::Warning,
614                        DIRTY_MESSAGE,
615                        &["Save", "Don't Save", "Cancel"],
616                    )
617                });
618                match answer.next().await {
619                    Some(0) => true,
620                    Some(1) => false,
621                    _ => return Ok(false),
622                }
623            } else {
624                true
625            };
626
627            if should_save {
628                if can_save {
629                    cx.update(|cx| item.save(project, cx)).await?;
630                } else if can_save_as {
631                    let start_abs_path = project
632                        .read_with(cx, |project, cx| {
633                            let worktree = project.visible_worktrees(cx).next()?;
634                            Some(worktree.read(cx).as_local()?.abs_path().to_path_buf())
635                        })
636                        .unwrap_or(Path::new("").into());
637
638                    let mut abs_path = cx.update(|cx| cx.prompt_for_new_path(&start_abs_path));
639                    if let Some(abs_path) = abs_path.next().await.flatten() {
640                        cx.update(|cx| item.save_as(project, abs_path, cx)).await?;
641                    } else {
642                        return Ok(false);
643                    }
644                }
645            }
646        }
647        Ok(true)
648    }
649
650    pub fn focus_active_item(&mut self, cx: &mut ViewContext<Self>) {
651        if let Some(active_item) = self.active_item() {
652            cx.focus(active_item);
653        }
654    }
655
656    pub fn split(&mut self, direction: SplitDirection, cx: &mut ViewContext<Self>) {
657        cx.emit(Event::Split(direction));
658    }
659
660    pub fn toolbar(&self) -> &ViewHandle<Toolbar> {
661        &self.toolbar
662    }
663
664    fn update_toolbar(&mut self, cx: &mut ViewContext<Self>) {
665        let active_item = self
666            .items
667            .get(self.active_item_index)
668            .map(|item| item.as_ref());
669        self.toolbar.update(cx, |toolbar, cx| {
670            toolbar.set_active_pane_item(active_item, cx);
671        });
672    }
673
674    fn render_tabs(&mut self, cx: &mut RenderContext<Self>) -> ElementBox {
675        let theme = cx.global::<Settings>().theme.clone();
676
677        enum Tabs {}
678        let pane = cx.handle();
679        let tabs = MouseEventHandler::new::<Tabs, _, _>(0, cx, |mouse_state, cx| {
680            let autoscroll = if mem::take(&mut self.autoscroll) {
681                Some(self.active_item_index)
682            } else {
683                None
684            };
685            let mut row = Flex::row().scrollable::<Tabs, _>(1, autoscroll, cx);
686            for (ix, item) in self.items.iter().enumerate() {
687                let is_active = ix == self.active_item_index;
688
689                row.add_child({
690                    let tab_style = if is_active {
691                        theme.workspace.active_tab.clone()
692                    } else {
693                        theme.workspace.tab.clone()
694                    };
695                    let title = item.tab_content(&tab_style, cx);
696
697                    let mut style = if is_active {
698                        theme.workspace.active_tab.clone()
699                    } else {
700                        theme.workspace.tab.clone()
701                    };
702                    if ix == 0 {
703                        style.container.border.left = false;
704                    }
705
706                    EventHandler::new(
707                        Container::new(
708                            Flex::row()
709                                .with_child(
710                                    Align::new({
711                                        let diameter = 7.0;
712                                        let icon_color = if item.has_conflict(cx) {
713                                            Some(style.icon_conflict)
714                                        } else if item.is_dirty(cx) {
715                                            Some(style.icon_dirty)
716                                        } else {
717                                            None
718                                        };
719
720                                        ConstrainedBox::new(
721                                            Canvas::new(move |bounds, _, cx| {
722                                                if let Some(color) = icon_color {
723                                                    let square = RectF::new(
724                                                        bounds.origin(),
725                                                        vec2f(diameter, diameter),
726                                                    );
727                                                    cx.scene.push_quad(Quad {
728                                                        bounds: square,
729                                                        background: Some(color),
730                                                        border: Default::default(),
731                                                        corner_radius: diameter / 2.,
732                                                    });
733                                                }
734                                            })
735                                            .boxed(),
736                                        )
737                                        .with_width(diameter)
738                                        .with_height(diameter)
739                                        .boxed()
740                                    })
741                                    .boxed(),
742                                )
743                                .with_child(
744                                    Container::new(Align::new(title).boxed())
745                                        .with_style(ContainerStyle {
746                                            margin: Margin {
747                                                left: style.spacing,
748                                                right: style.spacing,
749                                                ..Default::default()
750                                            },
751                                            ..Default::default()
752                                        })
753                                        .boxed(),
754                                )
755                                .with_child(
756                                    Align::new(
757                                        ConstrainedBox::new(if mouse_state.hovered {
758                                            let item_id = item.id();
759                                            enum TabCloseButton {}
760                                            let icon = Svg::new("icons/x.svg");
761                                            MouseEventHandler::new::<TabCloseButton, _, _>(
762                                                item_id,
763                                                cx,
764                                                |mouse_state, _| {
765                                                    if mouse_state.hovered {
766                                                        icon.with_color(style.icon_close_active)
767                                                            .boxed()
768                                                    } else {
769                                                        icon.with_color(style.icon_close).boxed()
770                                                    }
771                                                },
772                                            )
773                                            .with_padding(Padding::uniform(4.))
774                                            .with_cursor_style(CursorStyle::PointingHand)
775                                            .on_click({
776                                                let pane = pane.clone();
777                                                move |_, cx| {
778                                                    cx.dispatch_action(CloseItem {
779                                                        item_id,
780                                                        pane: pane.clone(),
781                                                    })
782                                                }
783                                            })
784                                            .named("close-tab-icon")
785                                        } else {
786                                            Empty::new().boxed()
787                                        })
788                                        .with_width(style.icon_width)
789                                        .boxed(),
790                                    )
791                                    .boxed(),
792                                )
793                                .boxed(),
794                        )
795                        .with_style(style.container)
796                        .boxed(),
797                    )
798                    .on_mouse_down(move |cx| {
799                        cx.dispatch_action(ActivateItem(ix));
800                        true
801                    })
802                    .boxed()
803                })
804            }
805
806            row.add_child(
807                Empty::new()
808                    .contained()
809                    .with_border(theme.workspace.tab.container.border)
810                    .flex(0., true)
811                    .named("filler"),
812            );
813
814            row.boxed()
815        });
816
817        ConstrainedBox::new(tabs.boxed())
818            .with_height(theme.workspace.tab.height)
819            .named("tabs")
820    }
821}
822
823impl Entity for Pane {
824    type Event = Event;
825}
826
827impl View for Pane {
828    fn ui_name() -> &'static str {
829        "Pane"
830    }
831
832    fn render(&mut self, cx: &mut RenderContext<Self>) -> ElementBox {
833        let this = cx.handle();
834
835        EventHandler::new(if let Some(active_item) = self.active_item() {
836            Flex::column()
837                .with_child(self.render_tabs(cx))
838                .with_child(ChildView::new(&self.toolbar).boxed())
839                .with_child(ChildView::new(active_item).flex(1., true).boxed())
840                .boxed()
841        } else {
842            Empty::new().boxed()
843        })
844        .on_navigate_mouse_down(move |direction, cx| {
845            let this = this.clone();
846            match direction {
847                NavigationDirection::Back => cx.dispatch_action(GoBack { pane: Some(this) }),
848                NavigationDirection::Forward => cx.dispatch_action(GoForward { pane: Some(this) }),
849            }
850
851            true
852        })
853        .named("pane")
854    }
855
856    fn on_focus(&mut self, cx: &mut ViewContext<Self>) {
857        self.focus_active_item(cx);
858    }
859}
860
861impl ItemNavHistory {
862    pub fn new<T: Item>(history: Rc<RefCell<NavHistory>>, item: &ViewHandle<T>) -> Self {
863        Self {
864            history,
865            item: Rc::new(item.downgrade()),
866        }
867    }
868
869    pub fn history(&self) -> Rc<RefCell<NavHistory>> {
870        self.history.clone()
871    }
872
873    pub fn push<D: 'static + Any>(&self, data: Option<D>) {
874        self.history.borrow_mut().push(data, self.item.clone());
875    }
876}
877
878impl NavHistory {
879    pub fn disable(&mut self) {
880        self.mode = NavigationMode::Disabled;
881    }
882
883    pub fn enable(&mut self) {
884        self.mode = NavigationMode::Normal;
885    }
886
887    pub fn pop_backward(&mut self) -> Option<NavigationEntry> {
888        self.backward_stack.pop_back()
889    }
890
891    pub fn pop_forward(&mut self) -> Option<NavigationEntry> {
892        self.forward_stack.pop_back()
893    }
894
895    fn pop(&mut self, mode: NavigationMode) -> Option<NavigationEntry> {
896        match mode {
897            NavigationMode::Normal | NavigationMode::Disabled => None,
898            NavigationMode::GoingBack => self.pop_backward(),
899            NavigationMode::GoingForward => self.pop_forward(),
900        }
901    }
902
903    fn set_mode(&mut self, mode: NavigationMode) {
904        self.mode = mode;
905    }
906
907    pub fn push<D: 'static + Any>(&mut self, data: Option<D>, item: Rc<dyn WeakItemHandle>) {
908        match self.mode {
909            NavigationMode::Disabled => {}
910            NavigationMode::Normal => {
911                if self.backward_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
912                    self.backward_stack.pop_front();
913                }
914                self.backward_stack.push_back(NavigationEntry {
915                    item,
916                    data: data.map(|data| Box::new(data) as Box<dyn Any>),
917                });
918                self.forward_stack.clear();
919            }
920            NavigationMode::GoingBack => {
921                if self.forward_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
922                    self.forward_stack.pop_front();
923                }
924                self.forward_stack.push_back(NavigationEntry {
925                    item,
926                    data: data.map(|data| Box::new(data) as Box<dyn Any>),
927                });
928            }
929            NavigationMode::GoingForward => {
930                if self.backward_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
931                    self.backward_stack.pop_front();
932                }
933                self.backward_stack.push_back(NavigationEntry {
934                    item,
935                    data: data.map(|data| Box::new(data) as Box<dyn Any>),
936                });
937            }
938        }
939    }
940}