Use sync.RWMutex in all widgets

Resolves #30.

CHANGELOG

@@ -3,6 +3,7 @@ v1.4.8 (WIP)
 - Add Modal.GetForm and Modal.GetFrame
 - Fix Form.Clear deadlock
 - Fill nil Flex space with default background color
+- Use sync.RWMutex in all widgets
 
 v1.4.7 (2020-06-09)
 - Add Box.SetBackgroundTransparent

DESIGN.md

@@ -0,0 +1,5 @@
+This document lists architectural details of cview.
+
+# Widgets always use `sync.RWMutex`
+
+See [#30](https://gitlab.com/tslocum/cview/-/issues/30).

button.go

@@ -29,7 +29,7 @@ type Button struct {
 	// key is provided indicating which key was pressed to leave (tab or backtab).
 	blur func(tcell.Key)
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewButton returns a new input field.
@@ -56,8 +56,8 @@ func (b *Button) SetLabel(label string) *Button {
 
 // GetLabel returns the button text.
 func (b *Button) GetLabel() string {
-	b.Lock()
-	defer b.Unlock()
+	b.RLock()
+	defer b.RUnlock()
 
 	return b.label
 }

checkbox.go

@@ -46,7 +46,7 @@ type CheckBox struct {
 	// this form item.
 	finished func(tcell.Key)
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewCheckBox returns a new input field.
@@ -70,8 +70,8 @@ func (c *CheckBox) SetChecked(checked bool) *CheckBox {
 
 // IsChecked returns whether or not the box is checked.
 func (c *CheckBox) IsChecked() bool {
-	c.Lock()
-	defer c.Unlock()
+	c.RLock()
+	defer c.RUnlock()
 
 	return c.checked
 }
@@ -87,8 +87,8 @@ func (c *CheckBox) SetLabel(label string) *CheckBox {
 
 // GetLabel returns the text to be displayed before the input area.
 func (c *CheckBox) GetLabel() string {
-	c.Lock()
-	defer c.Unlock()
+	c.RLock()
+	defer c.RUnlock()
 
 	return c.label
 }
@@ -104,8 +104,8 @@ func (c *CheckBox) SetMessage(message string) *CheckBox {
 
 // GetMessage returns the text to be displayed after the checkbox
 func (c *CheckBox) GetMessage() string {
-	c.Lock()
-	defer c.Unlock()
+	c.RLock()
+	defer c.RUnlock()
 
 	return c.message
 }
@@ -162,8 +162,8 @@ func (c *CheckBox) SetFormAttributes(labelWidth int, labelColor, bgColor, fieldT
 
 // GetFieldWidth returns this primitive's field width.
 func (c *CheckBox) GetFieldWidth() int {
-	c.Lock()
-	defer c.Unlock()
+	c.RLock()
+	defer c.RUnlock()
 
 	if c.message == "" {
 		return 1

flex.go

@@ -37,7 +37,7 @@ type Flex struct {
 	// instead its box dimensions.
 	fullScreen bool
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewFlex returns a new flexbox layout container with no primitives and its
@@ -217,8 +217,8 @@ func (f *Flex) Focus(delegate func(p Primitive)) {
 
 // HasFocus returns whether or not this primitive has focus.
 func (f *Flex) HasFocus() bool {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	for _, item := range f.items {
 		if item.Item != nil && item.Item.GetFocusable().HasFocus() {

form.go

@@ -84,7 +84,7 @@ type Form struct {
 	// An optional function which is called when the user hits Escape.
 	cancel func()
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewForm returns a new form.
@@ -285,8 +285,8 @@ func (f *Form) AddButton(label string, selected func()) *Form {
 // buttons have been specially prepared for this form and modifying some of
 // their attributes may have unintended side effects.
 func (f *Form) GetButton(index int) *Button {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	return f.buttons[index]
 }
@@ -303,8 +303,8 @@ func (f *Form) RemoveButton(index int) *Form {
 
 // GetButtonCount returns the number of buttons in this form.
 func (f *Form) GetButtonCount() int {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	return len(f.buttons)
 }
@@ -313,8 +313,8 @@ func (f *Form) GetButtonCount() int {
 // with 0 for the button that was added first. If no such label was found, -1
 // is returned.
 func (f *Form) GetButtonIndex(label string) int {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	for index, button := range f.buttons {
 		if button.GetLabel() == label {
@@ -368,8 +368,8 @@ func (f *Form) AddFormItem(item FormItem) *Form {
 // GetFormItemCount returns the number of items in the form (not including the
 // buttons).
 func (f *Form) GetFormItemCount() int {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	return len(f.items)
 }
@@ -378,8 +378,8 @@ func (f *Form) GetFormItemCount() int {
 // 0. Elements are referenced in the order they were added. Buttons are not
 // included.
 func (f *Form) GetFormItem(index int) FormItem {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	return f.items[index]
 }
@@ -399,8 +399,8 @@ func (f *Form) RemoveFormItem(index int) *Form {
 // no such element is found, nil is returned. Buttons are not searched and will
 // therefore not be returned.
 func (f *Form) GetFormItemByLabel(label string) FormItem {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	for _, item := range f.items {
 		if item.GetLabel() == label {
@@ -414,8 +414,8 @@ func (f *Form) GetFormItemByLabel(label string) FormItem {
 // label. If no such element is found, -1 is returned. Buttons are not searched
 // and will therefore not be returned.
 func (f *Form) GetFormItemIndex(label string) int {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	for index, item := range f.items {
 		if item.GetLabel() == label {
@@ -428,8 +428,8 @@ func (f *Form) GetFormItemIndex(label string) int {
 // GetFocusedItemIndex returns the indices of the form element or button which
 // currently has focus. If they don't, -1 is returned resepectively.
 func (f *Form) GetFocusedItemIndex() (formItem, button int) {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	index := f.focusIndex()
 	if index < 0 {

frame.go

@@ -28,7 +28,7 @@ type Frame struct {
 	// Border spacing.
 	top, bottom, header, footer, left, right int
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewFrame returns a new frame around the given primitive. The primitive's
@@ -167,8 +167,8 @@ func (f *Frame) Focus(delegate func(p Primitive)) {
 
 // HasFocus returns whether or not this primitive has focus.
 func (f *Frame) HasFocus() bool {
-	f.Lock()
-	defer f.Unlock()
+	f.RLock()
+	defer f.RUnlock()
 
 	focusable, ok := f.primitive.(Focusable)
 	if ok {

go.mod

@@ -8,5 +8,6 @@ require (
 	github.com/mattn/go-runewidth v0.0.9
 	github.com/rivo/uniseg v0.1.0
 	gitlab.com/tslocum/cbind v0.1.1
-	golang.org/x/sys v0.0.0-20200610111108-226ff32320da // indirect
+	golang.org/x/sys v0.0.0-20200802091954-4b90ce9b60b3 // indirect
+	golang.org/x/text v0.3.3 // indirect
 )

go.sum

@@ -23,11 +23,13 @@ gitlab.com/tslocum/cbind v0.1.1/go.mod h1:rX7vkl0pUSg/yy427MmD1FZAf99S7WwpUlxF/q
 golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756 h1:9nuHUbU8dRnRRfj9KjWUVrJeoexdbeMjttk6Oh1rD10=
 golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200202164722-d101bd2416d5/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200610111108-226ff32320da h1:bGb80FudwxpeucJUjPYJXuJ8Hk91vNtfvrymzwiei38=
-golang.org/x/sys v0.0.0-20200610111108-226ff32320da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200802091954-4b90ce9b60b3 h1:qDJKu1y/1SjhWac4BQZjLljqvqiWUhjmDMnonmVGDAU=
+golang.org/x/sys v0.0.0-20200802091954-4b90ce9b60b3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/text v0.3.3 h1:cokOdA+Jmi5PJGXLlLllQSgYigAEfHXJAERHVMaCc2k=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e h1:FDhOuMEY4JVRztM/gsbk+IKUQ8kj74bxZrgw87eMMVc=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

grid.go

@@ -56,7 +56,7 @@ type Grid struct {
 	// The color of the borders around grid items.
 	bordersColor tcell.Color
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewGrid returns a new grid-based layout container with no initial primitives.
@@ -272,8 +272,8 @@ func (g *Grid) SetOffset(rows, columns int) *Grid {
 // GetOffset returns the current row and column offset (see SetOffset() for
 // details).
 func (g *Grid) GetOffset() (rows, columns int) {
-	g.Lock()
-	defer g.Unlock()
+	g.RLock()
+	defer g.RUnlock()
 
 	return g.rowOffset, g.columnOffset
 }
@@ -306,8 +306,8 @@ func (g *Grid) Blur() {
 
 // HasFocus returns whether or not this primitive has focus.
 func (g *Grid) HasFocus() bool {
-	g.Lock()
-	defer g.Unlock()
+	g.RLock()
+	defer g.RUnlock()
 
 	for _, item := range g.items {
 		if item.visible && item.Item.GetFocusable().HasFocus() {

modal.go

@@ -31,7 +31,7 @@ type Modal struct {
 	// receives the index of the clicked button and the button's label.
 	done func(buttonIndex int, buttonLabel string)
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewModal returns a new centered message window.
@@ -121,16 +121,16 @@ func (m *Modal) SetText(text string) *Modal {
 // GetForm returns the Form embedded in the window. The returned Form may be
 // modified to include additional elements (e.g. AddInputField, AddFormItem).
 func (m *Modal) GetForm() *Form {
-	m.Lock()
-	defer m.Unlock()
+	m.RLock()
+	defer m.RUnlock()
 
 	return m.form
 }
 
 // GetFrame returns the Frame embedded in the window.
 func (m *Modal) GetFrame() *Frame {
-	m.Lock()
-	defer m.Unlock()
+	m.RLock()
+	defer m.RUnlock()
 
 	return m.frame
 }
@@ -188,10 +188,7 @@ func (m *Modal) Focus(delegate func(p Primitive)) {
 
 // HasFocus returns whether or not this primitive has focus.
 func (m *Modal) HasFocus() bool {
-	m.Lock()
-	defer m.Unlock()
-
-	return m.form.HasFocus()
+	return m.GetForm().HasFocus()
 }
 
 // Draw draws this primitive onto the screen.

pages.go

@@ -31,7 +31,7 @@ type Pages struct {
 	// pages changes.
 	changed func()
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewPages returns a new Pages object.
@@ -55,8 +55,8 @@ func (p *Pages) SetChangedFunc(handler func()) *Pages {
 
 // GetPageCount returns the number of pages currently stored in this object.
 func (p *Pages) GetPageCount() int {
-	p.Lock()
-	defer p.Unlock()
+	p.RLock()
+	defer p.RUnlock()
 
 	return len(p.pages)
 }
@@ -146,8 +146,8 @@ func (p *Pages) RemovePage(name string) *Pages {
 
 // HasPage returns true if a page with the given name exists in this object.
 func (p *Pages) HasPage(name string) bool {
-	p.Lock()
-	defer p.Unlock()
+	p.RLock()
+	defer p.RUnlock()
 
 	for _, page := range p.pages {
 		if page.Name == name {
@@ -301,8 +301,8 @@ func (p *Pages) SendToBack(name string) *Pages {
 // GetFrontPage returns the front-most visible page. If there are no visible
 // pages, ("", nil) is returned.
 func (p *Pages) GetFrontPage() (name string, item Primitive) {
-	p.Lock()
-	defer p.Unlock()
+	p.RLock()
+	defer p.RUnlock()
 
 	for index := len(p.pages) - 1; index >= 0; index-- {
 		if p.pages[index].Visible {
@@ -314,8 +314,8 @@ func (p *Pages) GetFrontPage() (name string, item Primitive) {
 
 // HasFocus returns whether or not this primitive has focus.
 func (p *Pages) HasFocus() bool {
-	p.Lock()
-	defer p.Unlock()
+	p.RLock()
+	defer p.RUnlock()
 
 	for _, page := range p.pages {
 		if page.Item.GetFocusable().HasFocus() {

progressbar.go

@@ -33,7 +33,7 @@ type ProgressBar struct {
 	// Progress required to fill the bar.
 	max int
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewProgressBar returns a new progress bar.
@@ -98,8 +98,8 @@ func (p *ProgressBar) SetMax(max int) {
 
 // GetMax returns the progress required to fill the bar.
 func (p *ProgressBar) GetMax() int {
-	p.Lock()
-	defer p.Unlock()
+	p.RLock()
+	defer p.RUnlock()
 
 	return p.max
 }
@@ -122,16 +122,16 @@ func (p *ProgressBar) SetProgress(progress int) {
 
 // GetProgress gets the current progress.
 func (p *ProgressBar) GetProgress() int {
-	p.Lock()
-	defer p.Unlock()
+	p.RLock()
+	defer p.RUnlock()
 
 	return p.progress
 }
 
 // Complete returns whether the progress bar has been filled.
 func (p *ProgressBar) Complete() bool {
-	p.Lock()
-	defer p.Unlock()
+	p.RLock()
+	defer p.RUnlock()
 
 	return p.progress >= p.max
 }

table.go

@@ -46,7 +46,7 @@ type TableCell struct {
 	// The position and width of the cell the last time table was drawn.
 	x, y, width int
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewTableCell returns a new table cell with sensible defaults. That is, left
@@ -178,8 +178,8 @@ func (c *TableCell) SetReference(reference interface{}) *TableCell {
 
 // GetReference returns this cell's reference object.
 func (c *TableCell) GetReference() interface{} {
-	c.Lock()
-	defer c.Unlock()
+	c.RLock()
+	defer c.RUnlock()
 
 	return c.Reference
 }
@@ -193,8 +193,8 @@ func (c *TableCell) GetReference() interface{} {
 // SetSelectedFunc()) or a "selectionChanged" event (see
 // SetSelectionChangedFunc()).
 func (c *TableCell) GetLastPosition() (x, y, width int) {
-	c.Lock()
-	defer c.Unlock()
+	c.RLock()
+	defer c.RUnlock()
 
 	return c.x, c.y, c.width
 }
@@ -319,7 +319,7 @@ type Table struct {
 	// or Backtab. Also when the user presses Enter if nothing is selectable.
 	done func(key tcell.Key)
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewTable returns a new table.
@@ -440,8 +440,8 @@ func (t *Table) SetSelectable(rows, columns bool) *Table {
 // GetSelectable returns what can be selected in a table. Refer to
 // SetSelectable() for details.
 func (t *Table) GetSelectable() (rows, columns bool) {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	return t.rowsSelectable, t.columnsSelectable
 }
@@ -450,8 +450,8 @@ func (t *Table) GetSelectable() (rows, columns bool) {
 // If entire rows are selected, the column index is undefined.
 // Likewise for entire columns.
 func (t *Table) GetSelection() (row, column int) {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	return t.selectedRow, t.selectedColumn
 }
@@ -491,8 +491,8 @@ func (t *Table) SetOffset(row, column int) *Table {
 // GetOffset returns the current row and column offset. This indicates how many
 // rows and columns the table is scrolled down and to the right.
 func (t *Table) GetOffset() (row, column int) {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	return t.rowOffset, t.columnOffset
 }
@@ -588,8 +588,8 @@ func (t *Table) SetCellSimple(row, column int, text string) *Table {
 // be inserted. Therefore, repeated calls to this function may return different
 // pointers for uninitialized cells.
 func (t *Table) GetCell(row, column int) *TableCell {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	if row >= len(t.cells) || column >= len(t.cells[row]) {
 		return &TableCell{}
@@ -665,16 +665,16 @@ func (t *Table) InsertColumn(column int) *Table {
 
 // GetRowCount returns the number of rows in the table.
 func (t *Table) GetRowCount() int {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	return len(t.cells)
 }
 
 // GetColumnCount returns the (maximum) number of columns in the table.
 func (t *Table) GetColumnCount() int {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	if len(t.cells) == 0 {
 		return 0

treeview.go

@@ -52,7 +52,7 @@ type TreeNode struct {
 	graphicsX int       // The x-coordinate of the left-most graphics rune.
 	textX     int       // The x-coordinate of the first rune of the text.
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewTreeNode returns a new tree node.
@@ -113,8 +113,8 @@ func (n *TreeNode) SetReference(reference interface{}) *TreeNode {
 
 // GetReference returns this node's reference object.
 func (n *TreeNode) GetReference() interface{} {
-	n.Lock()
-	defer n.Unlock()
+	n.RLock()
+	defer n.RUnlock()
 
 	return n.reference
 }
@@ -130,16 +130,16 @@ func (n *TreeNode) SetChildren(childNodes []*TreeNode) *TreeNode {
 
 // GetText returns this node's text.
 func (n *TreeNode) GetText() string {
-	n.Lock()
-	defer n.Unlock()
+	n.RLock()
+	defer n.RUnlock()
 
 	return n.text
 }
 
 // GetChildren returns this node's children.
 func (n *TreeNode) GetChildren() []*TreeNode {
-	n.Lock()
-	defer n.Unlock()
+	n.RLock()
+	defer n.RUnlock()
 
 	return n.children
 }
@@ -241,8 +241,8 @@ func (n *TreeNode) CollapseAll() *TreeNode {
 
 // IsExpanded returns whether the child nodes of this node are visible.
 func (n *TreeNode) IsExpanded() bool {
-	n.Lock()
-	defer n.Unlock()
+	n.RLock()
+	defer n.RUnlock()
 
 	return n.expanded
 }
@@ -258,8 +258,8 @@ func (n *TreeNode) SetText(text string) *TreeNode {
 
 // GetColor returns the node's color.
 func (n *TreeNode) GetColor() tcell.Color {
-	n.Lock()
-	defer n.Unlock()
+	n.RLock()
+	defer n.RUnlock()
 
 	return n.color
 }
@@ -363,7 +363,7 @@ type TreeView struct {
 	// The visible nodes, top-down, as set by process().
 	nodes []*TreeNode
 
-	sync.Mutex
+	sync.RWMutex
 }
 
 // NewTreeView returns a new tree view.
@@ -389,8 +389,8 @@ func (t *TreeView) SetRoot(root *TreeNode) *TreeView {
 // GetRoot returns the root node of the tree. If no such node was previously
 // set, nil is returned.
 func (t *TreeView) GetRoot() *TreeNode {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	return t.root
 }
@@ -416,8 +416,8 @@ func (t *TreeView) SetCurrentNode(node *TreeNode) *TreeView {
 // GetCurrentNode returns the currently selected node or nil of no node is
 // currently selected.
 func (t *TreeView) GetCurrentNode() *TreeNode {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	return t.currentNode
 }
@@ -532,8 +532,8 @@ func (t *TreeView) SetDoneFunc(handler func(key tcell.Key)) *TreeView {
 // of the tree view. Note that when the user navigates the tree view, this value
 // is only updated after the tree view has been redrawn.
 func (t *TreeView) GetScrollOffset() int {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	return t.offsetY
 }
@@ -543,8 +543,8 @@ func (t *TreeView) GetScrollOffset() int {
 // of collapsed nodes. Note that this value is only up to date after the tree
 // view has been drawn.
 func (t *TreeView) GetRowCount() int {
-	t.Lock()
-	defer t.Unlock()
+	t.RLock()
+	defer t.RUnlock()
 
 	return len(t.nodes)
 }