Rerender certain views when their width changes

Situations where a view's width changes:
- changing screen modes
- enter staging or patch building
- resizing the terminal window

For the first of these we currently have special code to force a rerender, since
some views render different content depending on whether they are in full-screen
mode. We'll be able to remove that code now, since this new generic mechanism
takes care of that too.

But we will need this more general mechanism for cases where views truncate
their content to the view width; we'll add one example for that later in this
branch.

pkg/gui/context/base_context.go

@@ -20,10 +20,11 @@ type BaseContext struct {
 	onFocusFn           onFocusFn
 	onFocusLostFn       onFocusLostFn
 
-	focusable           bool
+	focusable                  bool
-	transient           bool
+	transient                  bool
-	hasControlledBounds bool
+	hasControlledBounds        bool
-	highlightOnFocus    bool
+	needsRerenderOnWidthChange bool
+	highlightOnFocus           bool
 
 	*ParentContextMgr
 }
@@ -36,14 +37,15 @@ type (
 var _ types.IBaseContext = &BaseContext{}
 
 type NewBaseContextOpts struct {
-	Kind                  types.ContextKind
+	Kind                       types.ContextKind
-	Key                   types.ContextKey
+	Key                        types.ContextKey
-	View                  *gocui.View
+	View                       *gocui.View
-	WindowName            string
+	WindowName                 string
-	Focusable             bool
+	Focusable                  bool
-	Transient             bool
+	Transient                  bool
-	HasUncontrolledBounds bool // negating for the sake of making false the default
+	HasUncontrolledBounds      bool // negating for the sake of making false the default
-	HighlightOnFocus      bool
+	HighlightOnFocus           bool
+	NeedsRerenderOnWidthChange bool
 
 	OnGetOptionsMap func() map[string]string
 }
@@ -54,17 +56,18 @@ func NewBaseContext(opts NewBaseContextOpts) *BaseContext {
 	hasControlledBounds := !opts.HasUncontrolledBounds
 
 	return &BaseContext{
-		kind:                opts.Kind,
+		kind:                       opts.Kind,
-		key:                 opts.Key,
+		key:                        opts.Key,
-		view:                opts.View,
+		view:                       opts.View,
-		windowName:          opts.WindowName,
+		windowName:                 opts.WindowName,
-		onGetOptionsMap:     opts.OnGetOptionsMap,
+		onGetOptionsMap:            opts.OnGetOptionsMap,
-		focusable:           opts.Focusable,
+		focusable:                  opts.Focusable,
-		transient:           opts.Transient,
+		transient:                  opts.Transient,
-		hasControlledBounds: hasControlledBounds,
+		hasControlledBounds:        hasControlledBounds,
-		highlightOnFocus:    opts.HighlightOnFocus,
+		highlightOnFocus:           opts.HighlightOnFocus,
-		ParentContextMgr:    &ParentContextMgr{},
+		needsRerenderOnWidthChange: opts.NeedsRerenderOnWidthChange,
-		viewTrait:           viewTrait,
+		ParentContextMgr:           &ParentContextMgr{},
+		viewTrait:                  viewTrait,
 	}
 }
 
@@ -190,6 +193,10 @@ func (self *BaseContext) HasControlledBounds() bool {
 	return self.hasControlledBounds
 }
 
+func (self *BaseContext) NeedsRerenderOnWidthChange() bool {
+	return self.needsRerenderOnWidthChange
+}
+
 func (self *BaseContext) Title() string {
 	return ""
 }

pkg/gui/context/branches_context.go

@@ -40,11 +40,12 @@ func NewBranchesContext(c *ContextCommon) *BranchesContext {
 		FilteredListViewModel: viewModel,
 		ListContextTrait: &ListContextTrait{
 			Context: NewSimpleContext(NewBaseContext(NewBaseContextOpts{
-				View:       c.Views().Branches,
+				View:                       c.Views().Branches,
-				WindowName: "branches",
+				WindowName:                 "branches",
-				Key:        LOCAL_BRANCHES_CONTEXT_KEY,
+				Key:                        LOCAL_BRANCHES_CONTEXT_KEY,
-				Kind:       types.SIDE_CONTEXT,
+				Kind:                       types.SIDE_CONTEXT,
-				Focusable:  true,
+				Focusable:                  true,
+				NeedsRerenderOnWidthChange: true,
 			})),
 			ListRenderer: ListRenderer{
 				list:              viewModel,

pkg/gui/context/local_commits_context.go

@@ -68,11 +68,12 @@ func NewLocalCommitsContext(c *ContextCommon) *LocalCommitsContext {
 		SearchTrait:           NewSearchTrait(c),
 		ListContextTrait: &ListContextTrait{
 			Context: NewSimpleContext(NewBaseContext(NewBaseContextOpts{
-				View:       c.Views().Commits,
+				View:                       c.Views().Commits,
-				WindowName: "commits",
+				WindowName:                 "commits",
-				Key:        LOCAL_COMMITS_CONTEXT_KEY,
+				Key:                        LOCAL_COMMITS_CONTEXT_KEY,
-				Kind:       types.SIDE_CONTEXT,
+				Kind:                       types.SIDE_CONTEXT,
-				Focusable:  true,
+				Focusable:                  true,
+				NeedsRerenderOnWidthChange: true,
 			})),
 			ListRenderer: ListRenderer{
 				list:              viewModel,

pkg/gui/context/reflog_commits_context.go

@@ -43,11 +43,12 @@ func NewReflogCommitsContext(c *ContextCommon) *ReflogCommitsContext {
 		FilteredListViewModel: viewModel,
 		ListContextTrait: &ListContextTrait{
 			Context: NewSimpleContext(NewBaseContext(NewBaseContextOpts{
-				View:       c.Views().ReflogCommits,
+				View:                       c.Views().ReflogCommits,
-				WindowName: "commits",
+				WindowName:                 "commits",
-				Key:        REFLOG_COMMITS_CONTEXT_KEY,
+				Key:                        REFLOG_COMMITS_CONTEXT_KEY,
-				Kind:       types.SIDE_CONTEXT,
+				Kind:                       types.SIDE_CONTEXT,
-				Focusable:  true,
+				Focusable:                  true,
+				NeedsRerenderOnWidthChange: true,
 			})),
 			ListRenderer: ListRenderer{
 				list:              viewModel,

pkg/gui/context/remote_branches_context.go

@@ -36,12 +36,13 @@ func NewRemoteBranchesContext(
 		DynamicTitleBuilder:   NewDynamicTitleBuilder(c.Tr.RemoteBranchesDynamicTitle),
 		ListContextTrait: &ListContextTrait{
 			Context: NewSimpleContext(NewBaseContext(NewBaseContextOpts{
-				View:       c.Views().RemoteBranches,
+				View:                       c.Views().RemoteBranches,
-				WindowName: "branches",
+				WindowName:                 "branches",
-				Key:        REMOTE_BRANCHES_CONTEXT_KEY,
+				Key:                        REMOTE_BRANCHES_CONTEXT_KEY,
-				Kind:       types.SIDE_CONTEXT,
+				Kind:                       types.SIDE_CONTEXT,
-				Focusable:  true,
+				Focusable:                  true,
-				Transient:  true,
+				Transient:                  true,
+				NeedsRerenderOnWidthChange: true,
 			})),
 			ListRenderer: ListRenderer{
 				list:              viewModel,

pkg/gui/context/sub_commits_context.go

@@ -115,12 +115,13 @@ func NewSubCommitsContext(
 		DynamicTitleBuilder: NewDynamicTitleBuilder(c.Tr.SubCommitsDynamicTitle),
 		ListContextTrait: &ListContextTrait{
 			Context: NewSimpleContext(NewBaseContext(NewBaseContextOpts{
-				View:       c.Views().SubCommits,
+				View:                       c.Views().SubCommits,
-				WindowName: "branches",
+				WindowName:                 "branches",
-				Key:        SUB_COMMITS_CONTEXT_KEY,
+				Key:                        SUB_COMMITS_CONTEXT_KEY,
-				Kind:       types.SIDE_CONTEXT,
+				Kind:                       types.SIDE_CONTEXT,
-				Focusable:  true,
+				Focusable:                  true,
-				Transient:  true,
+				Transient:                  true,
+				NeedsRerenderOnWidthChange: true,
 			})),
 			ListRenderer: ListRenderer{
 				list:              viewModel,

pkg/gui/layout.go

@@ -44,8 +44,13 @@ func (gui *Gui) layout(g *gocui.Gui) error {
 		}
 	}
 
+	contextsToRerender := []types.Context{}
+
 	// we assume that the view has already been created.
-	setViewFromDimensions := func(viewName string, windowName string) (*gocui.View, error) {
+	setViewFromDimensions := func(context types.Context) (*gocui.View, error) {
+		viewName := context.GetViewName()
+		windowName := context.GetWindowName()
+
 		dimensionsObj, ok := viewDimensions[windowName]
 
 		view, err := g.View(viewName)
@@ -67,6 +72,16 @@ func (gui *Gui) layout(g *gocui.Gui) error {
 		if view.Frame {
 			frameOffset = 0
 		}
+
+		if context.NeedsRerenderOnWidthChange() {
+			// view.Width() returns the width -1 for some reason
+			oldWidth := view.Width() + 1
+			newWidth := dimensionsObj.X1 - dimensionsObj.X0 + 2*frameOffset
+			if oldWidth != newWidth {
+				contextsToRerender = append(contextsToRerender, context)
+			}
+		}
+
 		_, err = g.SetView(
 			viewName,
 			dimensionsObj.X0-frameOffset,
@@ -85,7 +100,7 @@ func (gui *Gui) layout(g *gocui.Gui) error {
 			continue
 		}
 
-		_, err := setViewFromDimensions(context.GetViewName(), context.GetWindowName())
+		_, err := setViewFromDimensions(context)
 		if err != nil && !gocui.IsUnknownView(err) {
 			return err
 		}
@@ -146,6 +161,12 @@ func (gui *Gui) layout(g *gocui.Gui) error {
 		}
 	}
 
+	for _, context := range contextsToRerender {
+		if err := context.HandleRender(); err != nil {
+			return err
+		}
+	}
+
 	// here is a good place log some stuff
 	// if you run `lazygit --logs`
 	// this will let you see these branches as prettified json

pkg/gui/types/context.go

@@ -60,6 +60,9 @@ type IBaseContext interface {
 	// determined independently.
 	HasControlledBounds() bool
 
+	// true if the view needs to be rerendered when its width changes
+	NeedsRerenderOnWidthChange() bool
+
 	// returns the desired title for the view upon activation. If there is no desired title (returns empty string), then
 	// no title will be set
 	Title() string