pane.rs

  1use super::{ItemHandle, SplitDirection};
  2use crate::{toolbar::Toolbar, Item, WeakItemHandle, Workspace};
  3use anyhow::Result;
  4use collections::{HashMap, HashSet, 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, 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    ChangeItemTitle,
113}
114
115pub struct Pane {
116    items: Vec<Box<dyn ItemHandle>>,
117    active_item_index: usize,
118    autoscroll: bool,
119    nav_history: Rc<RefCell<NavHistory>>,
120    toolbar: ViewHandle<Toolbar>,
121}
122
123pub struct ItemNavHistory {
124    history: Rc<RefCell<NavHistory>>,
125    item: Rc<dyn WeakItemHandle>,
126}
127
128#[derive(Default)]
129pub struct NavHistory {
130    mode: NavigationMode,
131    backward_stack: VecDeque<NavigationEntry>,
132    forward_stack: VecDeque<NavigationEntry>,
133    paths_by_item: HashMap<usize, ProjectPath>,
134}
135
136#[derive(Copy, Clone)]
137enum NavigationMode {
138    Normal,
139    GoingBack,
140    GoingForward,
141    Disabled,
142}
143
144impl Default for NavigationMode {
145    fn default() -> Self {
146        Self::Normal
147    }
148}
149
150pub struct NavigationEntry {
151    pub item: Rc<dyn WeakItemHandle>,
152    pub data: Option<Box<dyn Any>>,
153}
154
155impl Pane {
156    pub fn new(cx: &mut ViewContext<Self>) -> Self {
157        Self {
158            items: Vec::new(),
159            active_item_index: 0,
160            autoscroll: false,
161            nav_history: Default::default(),
162            toolbar: cx.add_view(|_| Toolbar::new()),
163        }
164    }
165
166    pub fn nav_history(&self) -> &Rc<RefCell<NavHistory>> {
167        &self.nav_history
168    }
169
170    pub fn activate(&self, cx: &mut ViewContext<Self>) {
171        cx.emit(Event::Activate);
172    }
173
174    pub fn go_back(
175        workspace: &mut Workspace,
176        pane: Option<ViewHandle<Pane>>,
177        cx: &mut ViewContext<Workspace>,
178    ) -> Task<()> {
179        Self::navigate_history(
180            workspace,
181            pane.unwrap_or_else(|| workspace.active_pane().clone()),
182            NavigationMode::GoingBack,
183            cx,
184        )
185    }
186
187    pub fn go_forward(
188        workspace: &mut Workspace,
189        pane: Option<ViewHandle<Pane>>,
190        cx: &mut ViewContext<Workspace>,
191    ) -> Task<()> {
192        Self::navigate_history(
193            workspace,
194            pane.unwrap_or_else(|| workspace.active_pane().clone()),
195            NavigationMode::GoingForward,
196            cx,
197        )
198    }
199
200    fn navigate_history(
201        workspace: &mut Workspace,
202        pane: ViewHandle<Pane>,
203        mode: NavigationMode,
204        cx: &mut ViewContext<Workspace>,
205    ) -> Task<()> {
206        workspace.activate_pane(pane.clone(), cx);
207
208        let to_load = pane.update(cx, |pane, cx| {
209            loop {
210                // Retrieve the weak item handle from the history.
211                let entry = pane.nav_history.borrow_mut().pop(mode)?;
212
213                // If the item is still present in this pane, then activate it.
214                if let Some(index) = entry
215                    .item
216                    .upgrade(cx)
217                    .and_then(|v| pane.index_for_item(v.as_ref()))
218                {
219                    let prev_active_item_index = pane.active_item_index;
220                    pane.nav_history.borrow_mut().set_mode(mode);
221                    pane.activate_item(index, true, true, cx);
222                    pane.nav_history
223                        .borrow_mut()
224                        .set_mode(NavigationMode::Normal);
225
226                    let mut navigated = prev_active_item_index != pane.active_item_index;
227                    if let Some(data) = entry.data {
228                        navigated |= pane.active_item()?.navigate(data, cx);
229                    }
230
231                    if navigated {
232                        break None;
233                    }
234                }
235                // If the item is no longer present in this pane, then retrieve its
236                // project path in order to reopen it.
237                else {
238                    break pane
239                        .nav_history
240                        .borrow_mut()
241                        .paths_by_item
242                        .get(&entry.item.id())
243                        .cloned()
244                        .map(|project_path| (project_path, entry));
245                }
246            }
247        });
248
249        if let Some((project_path, entry)) = to_load {
250            // If the item was no longer present, then load it again from its previous path.
251            let pane = pane.downgrade();
252            let task = workspace.load_path(project_path, cx);
253            cx.spawn(|workspace, mut cx| async move {
254                let task = task.await;
255                if let Some(pane) = pane.upgrade(&cx) {
256                    if let Some((project_entry_id, build_item)) = task.log_err() {
257                        pane.update(&mut cx, |pane, _| {
258                            pane.nav_history.borrow_mut().set_mode(mode);
259                        });
260                        let item = workspace.update(&mut cx, |workspace, cx| {
261                            Self::open_item(
262                                workspace,
263                                pane.clone(),
264                                project_entry_id,
265                                true,
266                                cx,
267                                build_item,
268                            )
269                        });
270                        pane.update(&mut cx, |pane, cx| {
271                            pane.nav_history
272                                .borrow_mut()
273                                .set_mode(NavigationMode::Normal);
274                            if let Some(data) = entry.data {
275                                item.navigate(data, cx);
276                            }
277                        });
278                    } else {
279                        workspace
280                            .update(&mut cx, |workspace, cx| {
281                                Self::navigate_history(workspace, pane, mode, cx)
282                            })
283                            .await;
284                    }
285                }
286            })
287        } else {
288            Task::ready(())
289        }
290    }
291
292    pub(crate) fn open_item(
293        workspace: &mut Workspace,
294        pane: ViewHandle<Pane>,
295        project_entry_id: ProjectEntryId,
296        focus_item: bool,
297        cx: &mut ViewContext<Workspace>,
298        build_item: impl FnOnce(&mut MutableAppContext) -> Box<dyn ItemHandle>,
299    ) -> Box<dyn ItemHandle> {
300        let existing_item = pane.update(cx, |pane, cx| {
301            for (ix, item) in pane.items.iter().enumerate() {
302                if item.project_entry_ids(cx).as_slice() == &[project_entry_id] {
303                    let item = item.boxed_clone();
304                    pane.activate_item(ix, true, focus_item, cx);
305                    return Some(item);
306                }
307            }
308            None
309        });
310        if let Some(existing_item) = existing_item {
311            existing_item
312        } else {
313            let item = build_item(cx);
314            Self::add_item(workspace, pane, item.boxed_clone(), true, focus_item, cx);
315            item
316        }
317    }
318
319    pub(crate) fn add_item(
320        workspace: &mut Workspace,
321        pane: ViewHandle<Pane>,
322        item: Box<dyn ItemHandle>,
323        activate_pane: bool,
324        focus_item: bool,
325        cx: &mut ViewContext<Workspace>,
326    ) {
327        // Prevent adding the same item to the pane more than once.
328        if let Some(item_ix) = pane.read(cx).items.iter().position(|i| i.id() == item.id()) {
329            pane.update(cx, |pane, cx| {
330                pane.activate_item(item_ix, activate_pane, focus_item, cx)
331            });
332            return;
333        }
334
335        item.set_nav_history(pane.read(cx).nav_history.clone(), cx);
336        item.added_to_pane(workspace, pane.clone(), cx);
337        pane.update(cx, |pane, cx| {
338            // If there is already an active item, then insert the new item
339            // right after it. Otherwise, adjust the `active_item_index` field
340            // before activating the new item, so that in the `activate_item`
341            // method, we can detect that the active item is changing.
342            let item_ix;
343            if pane.active_item_index < pane.items.len() {
344                item_ix = pane.active_item_index + 1
345            } else {
346                item_ix = pane.items.len();
347                pane.active_item_index = usize::MAX;
348            };
349
350            pane.items.insert(item_ix, item);
351            pane.activate_item(item_ix, activate_pane, focus_item, cx);
352            cx.notify();
353        });
354    }
355
356    pub fn items(&self) -> impl Iterator<Item = &Box<dyn ItemHandle>> {
357        self.items.iter()
358    }
359
360    pub fn items_of_type<'a, T: View>(&'a self) -> impl 'a + Iterator<Item = ViewHandle<T>> {
361        self.items
362            .iter()
363            .filter_map(|item| item.to_any().downcast())
364    }
365
366    pub fn active_item(&self) -> Option<Box<dyn ItemHandle>> {
367        self.items.get(self.active_item_index).cloned()
368    }
369
370    pub fn item_for_entry(
371        &self,
372        entry_id: ProjectEntryId,
373        cx: &AppContext,
374    ) -> Option<Box<dyn ItemHandle>> {
375        self.items.iter().find_map(|item| {
376            if item.is_singleton(cx) && item.project_entry_ids(cx).as_slice() == &[entry_id] {
377                Some(item.boxed_clone())
378            } else {
379                None
380            }
381        })
382    }
383
384    pub fn index_for_item(&self, item: &dyn ItemHandle) -> Option<usize> {
385        self.items.iter().position(|i| i.id() == item.id())
386    }
387
388    pub fn activate_item(
389        &mut self,
390        index: usize,
391        activate_pane: bool,
392        focus_item: bool,
393        cx: &mut ViewContext<Self>,
394    ) {
395        use NavigationMode::{GoingBack, GoingForward};
396        if index < self.items.len() {
397            let prev_active_item_ix = mem::replace(&mut self.active_item_index, index);
398            if prev_active_item_ix != self.active_item_index
399                || matches!(self.nav_history.borrow().mode, GoingBack | GoingForward)
400            {
401                if let Some(prev_item) = self.items.get(prev_active_item_ix) {
402                    prev_item.deactivated(cx);
403                }
404                cx.emit(Event::ActivateItem {
405                    local: activate_pane,
406                });
407            }
408            self.update_toolbar(cx);
409            if focus_item {
410                self.focus_active_item(cx);
411            }
412            if activate_pane {
413                self.activate(cx);
414            }
415            self.autoscroll = true;
416            cx.notify();
417        }
418    }
419
420    pub fn activate_prev_item(&mut self, cx: &mut ViewContext<Self>) {
421        let mut index = self.active_item_index;
422        if index > 0 {
423            index -= 1;
424        } else if self.items.len() > 0 {
425            index = self.items.len() - 1;
426        }
427        self.activate_item(index, true, true, cx);
428    }
429
430    pub fn activate_next_item(&mut self, cx: &mut ViewContext<Self>) {
431        let mut index = self.active_item_index;
432        if index + 1 < self.items.len() {
433            index += 1;
434        } else {
435            index = 0;
436        }
437        self.activate_item(index, true, true, cx);
438    }
439
440    pub fn close_active_item(
441        workspace: &mut Workspace,
442        _: &CloseActiveItem,
443        cx: &mut ViewContext<Workspace>,
444    ) -> Option<Task<Result<()>>> {
445        let pane_handle = workspace.active_pane().clone();
446        let pane = pane_handle.read(cx);
447        if pane.items.is_empty() {
448            None
449        } else {
450            let item_id_to_close = pane.items[pane.active_item_index].id();
451            let task = Self::close_items(workspace, pane_handle, cx, move |item_id| {
452                item_id == item_id_to_close
453            });
454            Some(cx.foreground().spawn(async move {
455                task.await?;
456                Ok(())
457            }))
458        }
459    }
460
461    pub fn close_inactive_items(
462        workspace: &mut Workspace,
463        _: &CloseInactiveItems,
464        cx: &mut ViewContext<Workspace>,
465    ) -> Option<Task<Result<()>>> {
466        let pane_handle = workspace.active_pane().clone();
467        let pane = pane_handle.read(cx);
468        if pane.items.is_empty() {
469            None
470        } else {
471            let active_item_id = pane.items[pane.active_item_index].id();
472            let task =
473                Self::close_items(workspace, pane_handle, cx, move |id| id != active_item_id);
474            Some(cx.foreground().spawn(async move {
475                task.await?;
476                Ok(())
477            }))
478        }
479    }
480
481    pub fn close_item(
482        workspace: &mut Workspace,
483        pane: ViewHandle<Pane>,
484        item_id_to_close: usize,
485        cx: &mut ViewContext<Workspace>,
486    ) -> Task<Result<bool>> {
487        Self::close_items(workspace, pane, cx, move |view_id| {
488            view_id == item_id_to_close
489        })
490    }
491
492    pub fn close_items(
493        workspace: &mut Workspace,
494        pane: ViewHandle<Pane>,
495        cx: &mut ViewContext<Workspace>,
496        should_close: impl 'static + Fn(usize) -> bool,
497    ) -> Task<Result<bool>> {
498        let project = workspace.project().clone();
499
500        // Find the items to close.
501        let mut items_to_close = Vec::new();
502        for item in &pane.read(cx).items {
503            if should_close(item.id()) {
504                items_to_close.push(item.boxed_clone());
505            }
506        }
507
508        // If a buffer is open both in a singleton editor and in a multibuffer, make sure
509        // to focus the singleton buffer when prompting to save that buffer, as opposed
510        // to focusing the multibuffer, because this gives the user a more clear idea
511        // of what content they would be saving.
512        items_to_close.sort_by_key(|item| !item.is_singleton(cx));
513
514        cx.spawn(|workspace, mut cx| async move {
515            let mut saved_project_entry_ids = HashSet::default();
516            for item in items_to_close.clone() {
517                // Find the item's current index and its set of project entries. Avoid
518                // storing these in advance, in case they have changed since this task
519                // was started.
520                let (item_ix, mut project_entry_ids) = pane.read_with(&cx, |pane, cx| {
521                    (pane.index_for_item(&*item), item.project_entry_ids(cx))
522                });
523                let item_ix = if let Some(ix) = item_ix {
524                    ix
525                } else {
526                    continue;
527                };
528
529                // If an item hasn't yet been associated with a project entry, then always
530                // prompt to save it before closing it. Otherwise, check if the item has
531                // any project entries that are not open anywhere else in the workspace,
532                // AND that the user has not already been prompted to save. If there are
533                // any such project entries, prompt the user to save this item.
534                let should_save = if project_entry_ids.is_empty() {
535                    true
536                } else {
537                    workspace.read_with(&cx, |workspace, cx| {
538                        for item in workspace.items(cx) {
539                            if !items_to_close
540                                .iter()
541                                .any(|item_to_close| item_to_close.id() == item.id())
542                            {
543                                let other_project_entry_ids = item.project_entry_ids(cx);
544                                project_entry_ids
545                                    .retain(|id| !other_project_entry_ids.contains(&id));
546                            }
547                        }
548                    });
549                    project_entry_ids
550                        .iter()
551                        .any(|id| saved_project_entry_ids.insert(*id))
552                };
553
554                if should_save {
555                    if !Self::save_item(project.clone(), &pane, item_ix, &item, true, &mut cx)
556                        .await?
557                    {
558                        break;
559                    }
560                }
561
562                // Remove the item from the pane.
563                pane.update(&mut cx, |pane, cx| {
564                    if let Some(item_ix) = pane.items.iter().position(|i| i.id() == item.id()) {
565                        if item_ix == pane.active_item_index {
566                            if item_ix + 1 < pane.items.len() {
567                                pane.activate_next_item(cx);
568                            } else if item_ix > 0 {
569                                pane.activate_prev_item(cx);
570                            }
571                        }
572
573                        let item = pane.items.remove(item_ix);
574                        if pane.items.is_empty() {
575                            item.deactivated(cx);
576                            pane.update_toolbar(cx);
577                            cx.emit(Event::Remove);
578                        }
579
580                        if item_ix < pane.active_item_index {
581                            pane.active_item_index -= 1;
582                        }
583
584                        let mut nav_history = pane.nav_history.borrow_mut();
585                        if let Some(path) = item.project_path(cx) {
586                            nav_history.paths_by_item.insert(item.id(), path);
587                        } else {
588                            nav_history.paths_by_item.remove(&item.id());
589                        }
590                    }
591                });
592            }
593
594            pane.update(&mut cx, |_, cx| cx.notify());
595            Ok(true)
596        })
597    }
598
599    pub async fn save_item(
600        project: ModelHandle<Project>,
601        pane: &ViewHandle<Pane>,
602        item_ix: usize,
603        item: &Box<dyn ItemHandle>,
604        should_prompt_for_save: bool,
605        cx: &mut AsyncAppContext,
606    ) -> Result<bool> {
607        const CONFLICT_MESSAGE: &'static str =
608            "This file has changed on disk since you started editing it. Do you want to overwrite it?";
609        const DIRTY_MESSAGE: &'static str =
610            "This file contains unsaved edits. Do you want to save it?";
611
612        let (has_conflict, is_dirty, can_save, is_singleton) = cx.read(|cx| {
613            (
614                item.has_conflict(cx),
615                item.is_dirty(cx),
616                item.can_save(cx),
617                item.is_singleton(cx),
618            )
619        });
620
621        if has_conflict && can_save {
622            let mut answer = pane.update(cx, |pane, cx| {
623                pane.activate_item(item_ix, true, true, cx);
624                cx.prompt(
625                    PromptLevel::Warning,
626                    CONFLICT_MESSAGE,
627                    &["Overwrite", "Discard", "Cancel"],
628                )
629            });
630            match answer.next().await {
631                Some(0) => cx.update(|cx| item.save(project, cx)).await?,
632                Some(1) => cx.update(|cx| item.reload(project, cx)).await?,
633                _ => return Ok(false),
634            }
635        } else if is_dirty && (can_save || is_singleton) {
636            let should_save = if should_prompt_for_save {
637                let mut answer = pane.update(cx, |pane, cx| {
638                    pane.activate_item(item_ix, true, true, cx);
639                    cx.prompt(
640                        PromptLevel::Warning,
641                        DIRTY_MESSAGE,
642                        &["Save", "Don't Save", "Cancel"],
643                    )
644                });
645                match answer.next().await {
646                    Some(0) => true,
647                    Some(1) => false,
648                    _ => return Ok(false),
649                }
650            } else {
651                true
652            };
653
654            if should_save {
655                if can_save {
656                    cx.update(|cx| item.save(project, cx)).await?;
657                } else if is_singleton {
658                    let start_abs_path = project
659                        .read_with(cx, |project, cx| {
660                            let worktree = project.visible_worktrees(cx).next()?;
661                            Some(worktree.read(cx).as_local()?.abs_path().to_path_buf())
662                        })
663                        .unwrap_or(Path::new("").into());
664
665                    let mut abs_path = cx.update(|cx| cx.prompt_for_new_path(&start_abs_path));
666                    if let Some(abs_path) = abs_path.next().await.flatten() {
667                        cx.update(|cx| item.save_as(project, abs_path, cx)).await?;
668                    } else {
669                        return Ok(false);
670                    }
671                }
672            }
673        }
674        Ok(true)
675    }
676
677    pub fn focus_active_item(&mut self, cx: &mut ViewContext<Self>) {
678        if let Some(active_item) = self.active_item() {
679            cx.focus(active_item);
680        }
681    }
682
683    pub fn split(&mut self, direction: SplitDirection, cx: &mut ViewContext<Self>) {
684        cx.emit(Event::Split(direction));
685    }
686
687    pub fn toolbar(&self) -> &ViewHandle<Toolbar> {
688        &self.toolbar
689    }
690
691    fn update_toolbar(&mut self, cx: &mut ViewContext<Self>) {
692        let active_item = self
693            .items
694            .get(self.active_item_index)
695            .map(|item| item.as_ref());
696        self.toolbar.update(cx, |toolbar, cx| {
697            toolbar.set_active_pane_item(active_item, cx);
698        });
699    }
700
701    fn render_tabs(&mut self, cx: &mut RenderContext<Self>) -> ElementBox {
702        let theme = cx.global::<Settings>().theme.clone();
703
704        enum Tabs {}
705        enum Tab {}
706        let pane = cx.handle();
707        let tabs = MouseEventHandler::new::<Tabs, _, _>(0, cx, |mouse_state, cx| {
708            let autoscroll = if mem::take(&mut self.autoscroll) {
709                Some(self.active_item_index)
710            } else {
711                None
712            };
713            let mut row = Flex::row().scrollable::<Tabs, _>(1, autoscroll, cx);
714            for (ix, item) in self.items.iter().enumerate() {
715                let is_active = ix == self.active_item_index;
716
717                row.add_child({
718                    let tab_style = if is_active {
719                        theme.workspace.active_tab.clone()
720                    } else {
721                        theme.workspace.tab.clone()
722                    };
723                    let title = item.tab_content(&tab_style, cx);
724
725                    let mut style = if is_active {
726                        theme.workspace.active_tab.clone()
727                    } else {
728                        theme.workspace.tab.clone()
729                    };
730                    if ix == 0 {
731                        style.container.border.left = false;
732                    }
733
734                    MouseEventHandler::new::<Tab, _, _>(ix, cx, |_, cx| {
735                        Container::new(
736                            Flex::row()
737                                .with_child(
738                                    Align::new({
739                                        let diameter = 7.0;
740                                        let icon_color = if item.has_conflict(cx) {
741                                            Some(style.icon_conflict)
742                                        } else if item.is_dirty(cx) {
743                                            Some(style.icon_dirty)
744                                        } else {
745                                            None
746                                        };
747
748                                        ConstrainedBox::new(
749                                            Canvas::new(move |bounds, _, cx| {
750                                                if let Some(color) = icon_color {
751                                                    let square = RectF::new(
752                                                        bounds.origin(),
753                                                        vec2f(diameter, diameter),
754                                                    );
755                                                    cx.scene.push_quad(Quad {
756                                                        bounds: square,
757                                                        background: Some(color),
758                                                        border: Default::default(),
759                                                        corner_radius: diameter / 2.,
760                                                    });
761                                                }
762                                            })
763                                            .boxed(),
764                                        )
765                                        .with_width(diameter)
766                                        .with_height(diameter)
767                                        .boxed()
768                                    })
769                                    .boxed(),
770                                )
771                                .with_child(
772                                    Container::new(Align::new(title).boxed())
773                                        .with_style(ContainerStyle {
774                                            margin: Margin {
775                                                left: style.spacing,
776                                                right: style.spacing,
777                                                ..Default::default()
778                                            },
779                                            ..Default::default()
780                                        })
781                                        .boxed(),
782                                )
783                                .with_child(
784                                    Align::new(
785                                        ConstrainedBox::new(if mouse_state.hovered {
786                                            let item_id = item.id();
787                                            enum TabCloseButton {}
788                                            let icon = Svg::new("icons/x.svg");
789                                            MouseEventHandler::new::<TabCloseButton, _, _>(
790                                                item_id,
791                                                cx,
792                                                |mouse_state, _| {
793                                                    if mouse_state.hovered {
794                                                        icon.with_color(style.icon_close_active)
795                                                            .boxed()
796                                                    } else {
797                                                        icon.with_color(style.icon_close).boxed()
798                                                    }
799                                                },
800                                            )
801                                            .with_padding(Padding::uniform(4.))
802                                            .with_cursor_style(CursorStyle::PointingHand)
803                                            .on_click({
804                                                let pane = pane.clone();
805                                                move |_, _, cx| {
806                                                    cx.dispatch_action(CloseItem {
807                                                        item_id,
808                                                        pane: pane.clone(),
809                                                    })
810                                                }
811                                            })
812                                            .named("close-tab-icon")
813                                        } else {
814                                            Empty::new().boxed()
815                                        })
816                                        .with_width(style.icon_width)
817                                        .boxed(),
818                                    )
819                                    .boxed(),
820                                )
821                                .boxed(),
822                        )
823                        .with_style(style.container)
824                        .boxed()
825                    })
826                    .on_mouse_down(move |_, cx| {
827                        cx.dispatch_action(ActivateItem(ix));
828                    })
829                    .boxed()
830                })
831            }
832
833            row.add_child(
834                Empty::new()
835                    .contained()
836                    .with_border(theme.workspace.tab.container.border)
837                    .flex(0., true)
838                    .named("filler"),
839            );
840
841            row.boxed()
842        });
843
844        ConstrainedBox::new(tabs.boxed())
845            .with_height(theme.workspace.tab.height)
846            .named("tabs")
847    }
848}
849
850impl Entity for Pane {
851    type Event = Event;
852}
853
854impl View for Pane {
855    fn ui_name() -> &'static str {
856        "Pane"
857    }
858
859    fn render(&mut self, cx: &mut RenderContext<Self>) -> ElementBox {
860        let this = cx.handle();
861
862        EventHandler::new(if let Some(active_item) = self.active_item() {
863            Flex::column()
864                .with_child(self.render_tabs(cx))
865                .with_child(ChildView::new(&self.toolbar).boxed())
866                .with_child(ChildView::new(active_item).flex(1., true).boxed())
867                .boxed()
868        } else {
869            Empty::new().boxed()
870        })
871        .on_navigate_mouse_down(move |direction, cx| {
872            let this = this.clone();
873            match direction {
874                NavigationDirection::Back => cx.dispatch_action(GoBack { pane: Some(this) }),
875                NavigationDirection::Forward => cx.dispatch_action(GoForward { pane: Some(this) }),
876            }
877
878            true
879        })
880        .named("pane")
881    }
882
883    fn on_focus(&mut self, cx: &mut ViewContext<Self>) {
884        self.focus_active_item(cx);
885    }
886}
887
888impl ItemNavHistory {
889    pub fn new<T: Item>(history: Rc<RefCell<NavHistory>>, item: &ViewHandle<T>) -> Self {
890        Self {
891            history,
892            item: Rc::new(item.downgrade()),
893        }
894    }
895
896    pub fn history(&self) -> Rc<RefCell<NavHistory>> {
897        self.history.clone()
898    }
899
900    pub fn push<D: 'static + Any>(&self, data: Option<D>) {
901        self.history.borrow_mut().push(data, self.item.clone());
902    }
903}
904
905impl NavHistory {
906    pub fn disable(&mut self) {
907        self.mode = NavigationMode::Disabled;
908    }
909
910    pub fn enable(&mut self) {
911        self.mode = NavigationMode::Normal;
912    }
913
914    pub fn pop_backward(&mut self) -> Option<NavigationEntry> {
915        self.backward_stack.pop_back()
916    }
917
918    pub fn pop_forward(&mut self) -> Option<NavigationEntry> {
919        self.forward_stack.pop_back()
920    }
921
922    fn pop(&mut self, mode: NavigationMode) -> Option<NavigationEntry> {
923        match mode {
924            NavigationMode::Normal | NavigationMode::Disabled => None,
925            NavigationMode::GoingBack => self.pop_backward(),
926            NavigationMode::GoingForward => self.pop_forward(),
927        }
928    }
929
930    fn set_mode(&mut self, mode: NavigationMode) {
931        self.mode = mode;
932    }
933
934    pub fn push<D: 'static + Any>(&mut self, data: Option<D>, item: Rc<dyn WeakItemHandle>) {
935        match self.mode {
936            NavigationMode::Disabled => {}
937            NavigationMode::Normal => {
938                if self.backward_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
939                    self.backward_stack.pop_front();
940                }
941                self.backward_stack.push_back(NavigationEntry {
942                    item,
943                    data: data.map(|data| Box::new(data) as Box<dyn Any>),
944                });
945                self.forward_stack.clear();
946            }
947            NavigationMode::GoingBack => {
948                if self.forward_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
949                    self.forward_stack.pop_front();
950                }
951                self.forward_stack.push_back(NavigationEntry {
952                    item,
953                    data: data.map(|data| Box::new(data) as Box<dyn Any>),
954                });
955            }
956            NavigationMode::GoingForward => {
957                if self.backward_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
958                    self.backward_stack.pop_front();
959                }
960                self.backward_stack.push_back(NavigationEntry {
961                    item,
962                    data: data.map(|data| Box::new(data) as Box<dyn Any>),
963                });
964            }
965        }
966    }
967}