First pass at filter support.

Press / to input a filter string. The proc list will be filtered to
procs that contain the filter as a substring of either the command or
the string representation of the PID.

README.md

@@ -71,7 +71,7 @@ snap connect gotop-cjbassi:system-observe
 ### Keybinds
 
 - Quit: `q` or `<C-c>`
-- Process navigation
+- Process navigation:
   - `k` and `<Up>`: up
   - `j` and `<Down`: down
   - `<C-u>`: half page up
@@ -83,10 +83,15 @@ snap connect gotop-cjbassi:system-observe
 - Process actions:
   - `<Tab>`: toggle process grouping
   - `dd`: kill selected process or group of processes
-- Process sorting
+- Process sorting:
   - `c`: CPU
   - `m`: Mem
   - `p`: PID
+- Process filtering:
+  - /: start editing filter
+	- (while editing):
+		- <Enter> accept filter
+		- <C-c>: clear filter
 - CPU and Mem graph scaling:
   - `h`: scale in
   - `l`: scale out

main.go

@@ -12,6 +12,7 @@ import (
 	"strconv"
 	"syscall"
 	"time"
+	"unicode/utf8"
 
 	docopt "github.com/docopt/docopt.go"
 	ui "github.com/gizak/termui/v3"
@@ -296,12 +297,8 @@ func eventLoop() {
 				}
 			}
 		case e := <-uiEvents:
-			switch e.ID {
-			case "q", "<C-c>":
-				return
-			case "?":
-				helpVisible = !helpVisible
-			case "<Resize>":
+			// Handle resize event always.
+			if e.ID == "<Resize>" {
 				payload := e.Payload.(ui.Resize)
 				termWidth, termHeight := payload.Width, payload.Height
 				if statusbar {
@@ -312,23 +309,55 @@ func eventLoop() {
 				}
 				help.Resize(payload.Width, payload.Height)
 				ui.Clear()
+
+				if helpVisible {
+					ui.Render(help)
+				} else {
+					ui.Render(grid)
+					if statusbar {
+						ui.Render(bar)
+					}
+				}
 			}
 
-			if helpVisible {
+			if proc.EditingFilter() {
+				if utf8.RuneCountInString(e.ID) == 1 {
+					proc.SetFilter(proc.Filter() + e.ID)
+					ui.Render(proc)
+				}
 				switch e.ID {
+				case "<C-c>":
+					proc.SetFilter("")
+					proc.SetEditingFilter(false)
+					ui.Render(proc)
+				case "<Enter>":
+					proc.SetEditingFilter(false)
+					ui.Render(proc)
+				case "<Backspace>":
+					if filter := proc.Filter(); filter != "" {
+						proc.SetFilter(filter[:len(filter)-1])
+					}
+					ui.Render(proc)
+				}
+			} else if helpVisible {
+				switch e.ID {
+				case "q", "<C-c>":
+					return
 				case "?":
-					ui.Clear()
-					ui.Render(help)
+					helpVisible = false
+					ui.Render(grid)
 				case "<Escape>":
 					helpVisible = false
 					ui.Render(grid)
-				case "<Resize>":
-					ui.Render(help)
 				}
 			} else {
 				switch e.ID {
+				case "q", "<C-c>":
+					return
 				case "?":
-					ui.Render(grid)
+					helpVisible = true
+					ui.Clear()
+					ui.Render(help)
 				case "h":
 					graphHorizontalScale += graphHorizontalScaleDelta
 					cpu.HorizontalScale = graphHorizontalScale
@@ -341,11 +370,6 @@ func eventLoop() {
 						mem.HorizontalScale = graphHorizontalScale
 						ui.Render(cpu, mem)
 					}
-				case "<Resize>":
-					ui.Render(grid)
-					if statusbar {
-						ui.Render(bar)
-					}
 				case "<MouseLeft>":
 					payload := e.Payload.(ui.Mouse)
 					proc.HandleClick(payload.X, payload.Y)
@@ -389,6 +413,10 @@ func eventLoop() {
 				case "m", "c", "p":
 					proc.ChangeProcSortMethod(w.ProcSortMethod(e.ID))
 					ui.Render(proc)
+				case "/":
+					proc.SetFilter("")
+					proc.SetEditingFilter(true)
+					ui.Render(proc)
 				}
 
 				if previousKey == e.ID {

src/widgets/help.go

@@ -10,7 +10,7 @@ import (
 const KEYBINDS = `
 Quit: q or <C-c>
 
-Process navigation
+Process navigation:
   - k and <Up>: up
   - j and <Down>: down
   - <C-u>: half page up
@@ -24,11 +24,17 @@ Process actions:
   - <Tab>: toggle process grouping
   - dd: kill selected process or group of processes
 
-Process sorting
+Process sorting:
   - c: CPU
   - m: Mem
   - p: PID
 
+Process filtering:
+  - /: start editing filter
+  - (while editing):
+    - <Enter>: accept filter
+    - <C-c> clear filter
+
 CPU and Mem graph scaling:
   - h: scale in
   - l: scale out
@@ -46,7 +52,7 @@ func NewHelpMenu() *HelpMenu {
 
 func (self *HelpMenu) Resize(termWidth, termHeight int) {
 	textWidth := 53
-	textHeight := 22
+	textHeight := strings.Count(KEYBINDS, "\n") + 1
 	x := (termWidth - textWidth) / 2
 	y := (termHeight - textHeight) / 2
 

src/widgets/proc.go

@@ -2,21 +2,26 @@ package widgets
 
 import (
 	"fmt"
+	"image"
 	"log"
 	"os/exec"
 	"sort"
 	"strconv"
+	"strings"
 	"time"
+	"unicode/utf8"
 
 	psCPU "github.com/shirou/gopsutil/cpu"
 
 	ui "github.com/cjbassi/gotop/src/termui"
 	"github.com/cjbassi/gotop/src/utils"
+	tui "github.com/gizak/termui/v3"
 )
 
 const (
 	UP_ARROW   = "▲"
 	DOWN_ARROW = "▼"
+	ELLIPSIS   = "…"
 )
 
 type ProcSortMethod string
@@ -40,6 +45,8 @@ type ProcWidget struct {
 	cpuCount         int
 	updateInterval   time.Duration
 	sortMethod       ProcSortMethod
+	filter           string
+	editingFilter    bool
 	groupedProcs     []Proc
 	ungroupedProcs   []Proc
 	showGroupedProcs bool
@@ -56,6 +63,8 @@ func NewProcWidget() *ProcWidget {
 		cpuCount:         cpuCount,
 		sortMethod:       ProcSortCpu,
 		showGroupedProcs: true,
+		filter:           "",
+		editingFilter:    false,
 	}
 	self.Title = " Processes "
 	self.ShowCursor = true
@@ -86,6 +95,71 @@ func NewProcWidget() *ProcWidget {
 	return self
 }
 
+func (self *ProcWidget) Filter() string {
+	return self.filter
+}
+
+func (self *ProcWidget) SetFilter(filter string) {
+	self.filter = filter
+}
+
+func (self *ProcWidget) EditingFilter() bool {
+	return self.editingFilter
+}
+
+func (self *ProcWidget) SetEditingFilter(editing bool) {
+	self.editingFilter = editing
+	if !editing {
+		self.update()
+	}
+}
+
+func (self *ProcWidget) Draw(buf *tui.Buffer) {
+	self.Table.Draw(buf)
+	if self.filter != "" || self.editingFilter {
+		self.drawFilter(buf)
+	}
+}
+
+func (self *ProcWidget) drawFilter(buf *tui.Buffer) {
+	style := self.TitleStyle
+	label := "Filter: "
+	if self.editingFilter {
+		label = "[ Filter: "
+		style = tui.NewStyle(style.Fg, style.Bg, tui.ModifierBold)
+	}
+
+	p := image.Pt(self.Min.X+2, self.Max.Y-1)
+	buf.SetString(label, style, p)
+	p.X += utf8.RuneCountInString(label)
+
+	maxLen := self.Max.X - p.X - 4
+	filter := self.filter
+	if l := utf8.RuneCountInString(filter); l > maxLen {
+		filter = ELLIPSIS + filter[l-maxLen+1:]
+	}
+	buf.SetString(filter, self.TitleStyle, p)
+	p.X += utf8.RuneCountInString(filter)
+
+	if self.editingFilter {
+		remaining := self.Max.X - 2 - p.X
+		buf.SetString(fmt.Sprintf("%*s", remaining, "]"), style, p)
+	}
+}
+
+func (self *ProcWidget) filterProcs(procs []Proc) []Proc {
+	if self.filter == "" {
+		return procs
+	}
+	var filtered []Proc
+	for _, proc := range procs {
+		if strings.Contains(proc.FullCommand, self.filter) || strings.Contains(fmt.Sprintf("%d", proc.Pid), self.filter) {
+			filtered = append(filtered, proc)
+		}
+	}
+	return filtered
+}
+
 func (self *ProcWidget) update() {
 	procs, err := getProcs()
 	if err != nil {
@@ -98,6 +172,7 @@ func (self *ProcWidget) update() {
 		procs[i].Cpu /= float64(self.cpuCount)
 	}
 
+	procs = self.filterProcs(procs)
 	self.ungroupedProcs = procs
 	self.groupedProcs = groupProcs(procs)