Fix data race between rendering and updating

9 files changed, 61 insertions, 39 deletions

diff --git a/main.go b/main.go
index 6dbac9d..dcff042 100644
--- a/main.go
+++ b/main.go
@@ -10,6 +10,7 @@ import (
 	"path/filepath"
 	"sort"
 	"strconv"
+	"sync"
 	"syscall"
 	"time"
 
@@ -46,6 +47,8 @@ var (
 	battery        = false
 	statusbar      = false
 
+	renderLock sync.RWMutex
+
 	cpu  *w.CPU
 	batt *w.Batt
 	mem  *w.Mem
@@ -257,20 +260,26 @@ func widgetColors() {
 }
 
 func initWidgets() {
-	cpu = w.NewCPU(updateInterval, graphHorizontalScale, averageLoad, percpuLoad)
-	mem = w.NewMem(updateInterval, graphHorizontalScale)
-	proc = w.NewProc()
+	cpu = w.NewCPU(&renderLock, updateInterval, graphHorizontalScale, averageLoad, percpuLoad)
+	mem = w.NewMem(&renderLock, updateInterval, graphHorizontalScale)
+	proc = w.NewProc(&renderLock)
 	help = w.NewHelpMenu()
 	if !minimalMode {
 		if battery {
-			batt = w.NewBatt(graphHorizontalScale)
+			batt = w.NewBatt(&renderLock, graphHorizontalScale)
 		}
-		net = w.NewNet()
-		disk = w.NewDisk()
-		temp = w.NewTemp(fahrenheit)
+		net = w.NewNet(&renderLock)
+		disk = w.NewDisk(&renderLock)
+		temp = w.NewTemp(&renderLock, fahrenheit)
 	}
 }
 
+func render(drawable ...ui.Drawable) {
+	renderLock.Lock()
+	ui.Render(drawable...)
+	renderLock.Unlock()
+}
+
 func eventLoop() {
 	drawTicker := time.NewTicker(updateInterval).C
 
@@ -288,7 +297,7 @@ func eventLoop() {
 			return
 		case <-drawTicker:
 			if !helpVisible {
-				ui.Render(grid)
+				render(grid)
 			}
 		case e := <-uiEvents:
 			switch e.ID {
@@ -310,68 +319,68 @@ func eventLoop() {
 					ui.Render(help)
 				case "<Escape>":
 					helpVisible = false
-					ui.Render(grid)
+					render(grid)
 				case "<Resize>":
 					ui.Render(help)
 				}
 			} else {
 				switch e.ID {
 				case "?":
-					ui.Render(grid)
+					render(grid)
 				case "h":
 					graphHorizontalScale += graphHorizontalScaleDelta
 					cpu.HorizontalScale = graphHorizontalScale
 					mem.HorizontalScale = graphHorizontalScale
-					ui.Render(cpu, mem)
+					render(cpu, mem)
 				case "l":
 					if graphHorizontalScale > graphHorizontalScaleDelta {
 						graphHorizontalScale -= graphHorizontalScaleDelta
 						cpu.HorizontalScale = graphHorizontalScale
 						mem.HorizontalScale = graphHorizontalScale
-						ui.Render(cpu, mem)
+						render(cpu, mem)
 					}
 				case "<Resize>":
-					ui.Render(grid)
+					render(grid)
 				case "<MouseLeft>":
 					payload := e.Payload.(ui.Mouse)
 					proc.Click(payload.X, payload.Y)
-					ui.Render(proc)
+					render(proc)
 				case "k", "<Up>", "<MouseWheelUp>":
 					proc.Up()
-					ui.Render(proc)
+					render(proc)
 				case "j", "<Down>", "<MouseWheelDown>":
 					proc.Down()
-					ui.Render(proc)
+					render(proc)
 				case "g", "<Home>":
 					if previousKey == "g" {
 						proc.Top()
-						ui.Render(proc)
+						render(proc)
 					}
 				case "G", "<End>":
 					proc.Bottom()
-					ui.Render(proc)
+					render(proc)
 				case "<C-d>":
 					proc.HalfPageDown()
-					ui.Render(proc)
+					render(proc)
 				case "<C-u>":
 					proc.HalfPageUp()
-					ui.Render(proc)
+					render(proc)
 				case "<C-f>":
 					proc.PageDown()
-					ui.Render(proc)
+					render(proc)
 				case "<C-b>":
 					proc.PageUp()
-					ui.Render(proc)
+					render(proc)
 				case "d":
 					if previousKey == "d" {
 						proc.Kill()
 					}
 				case "<Tab>":
 					proc.Tab()
-					ui.Render(proc)
+					render(proc)
 				case "m", "c", "p":
 					proc.ChangeSort(e)
-					ui.Render(proc)
+					render(proc)
 				}
 
 				if previousKey == e.ID {
diff --git a/src/termui/table.go b/src/termui/table.go
index 76e87f5..83d4849 100644
--- a/src/termui/table.go
+++ b/src/termui/table.go
@@ -3,7 +3,6 @@ package termui
 import (
 	"image"
 	"strings"
-	"sync"
 
 	. "github.com/gizak/termui"
 )
@@ -12,8 +11,6 @@ import (
 type Table struct {
 	*Block
 
-	sync.Mutex
-
 	Header []string
 	Rows   [][]string
 
@@ -51,8 +48,6 @@ func (self *Table) ColResize() {
 }
 
 func (self *Table) Draw(buf *Buffer) {
-	self.Lock()
-
 	self.Block.Draw(buf)
 
 	self.ColResizer()
@@ -128,7 +123,6 @@ func (self *Table) Draw(buf *Buffer) {
 			)
 		}
 	}
-	self.Unlock()
 }
 
 /////////////////////////////////////////////////////////////////////////////////
diff --git a/src/widgets/battery.go b/src/widgets/battery.go
index 3f211a8..77a5c03 100644
--- a/src/widgets/battery.go
+++ b/src/widgets/battery.go
@@ -5,6 +5,7 @@ import (
 	"log"
 	"math"
 	"strconv"
+	"sync"
 	"time"
 
 	ui "github.com/cjbassi/gotop/src/termui"
@@ -17,7 +18,7 @@ type Batt struct {
 	interval time.Duration
 }
 
-func NewBatt(horizontalScale int) *Batt {
+func NewBatt(renderLock *sync.RWMutex, horizontalScale int) *Batt {
 	batts, err := battery.GetAll()
 	self := &Batt{
 		LineGraph: ui.NewLineGraph(),
@@ -39,7 +40,9 @@ func NewBatt(horizontalScale int) *Batt {
 	go func() {
 		ticker := time.NewTicker(self.interval)
 		for range ticker.C {
+			renderLock.RLock()
 			self.update()
+			renderLock.RUnlock()
 		}
 	}()
 
diff --git a/src/widgets/cpu.go b/src/widgets/cpu.go
index 8ae44e7..4502fa8 100644
--- a/src/widgets/cpu.go
+++ b/src/widgets/cpu.go
@@ -3,6 +3,7 @@ package widgets
 import (
 	"fmt"
 	"log"
+	"sync"
 	"time"
 
 	ui "github.com/cjbassi/gotop/src/termui"
@@ -18,7 +19,7 @@ type CPU struct {
 	formatString string
 }
 
-func NewCPU(interval time.Duration, horizontalScale int, average bool, percpu bool) *CPU {
+func NewCPU(renderLock *sync.RWMutex, interval time.Duration, horizontalScale int, average bool, percpu bool) *CPU {
 	count, err := psCPU.Counts(false)
 	if err != nil {
 		log.Printf("failed to get CPU count from gopsutil: %v", err)
@@ -62,7 +63,9 @@ func NewCPU(interval time.Duration, horizontalScale int, average bool, percpu bo
 	go func() {
 		ticker := time.NewTicker(self.interval)
 		for range ticker.C {
+			renderLock.RLock()
 			self.update()
+			renderLock.RUnlock()
 		}
 	}()
 
diff --git a/src/widgets/disk.go b/src/widgets/disk.go
index fe2315b..f7392df 100644
--- a/src/widgets/disk.go
+++ b/src/widgets/disk.go
@@ -5,6 +5,7 @@ import (
 	"log"
 	"sort"
 	"strings"
+	"sync"
 	"time"
 
 	ui "github.com/cjbassi/gotop/src/termui"
@@ -29,7 +30,7 @@ type Disk struct {
 	Partitions map[string]*Partition
 }
 
-func NewDisk() *Disk {
+func NewDisk(renderLock *sync.RWMutex) *Disk {
 	self := &Disk{
 		Table:      ui.NewTable(),
 		interval:   time.Second,
@@ -45,7 +46,9 @@ func NewDisk() *Disk {
 	go func() {
 		ticker := time.NewTicker(self.interval)
 		for range ticker.C {
+			renderLock.RLock()
 			self.update()
+			renderLock.RUnlock()
 		}
 	}()
 
diff --git a/src/widgets/mem.go b/src/widgets/mem.go
index 906da9b..4c5a3a5 100644
--- a/src/widgets/mem.go
+++ b/src/widgets/mem.go
@@ -3,6 +3,7 @@ package widgets
 import (
 	"fmt"
 	"log"
+	"sync"
 	"time"
 
 	ui "github.com/cjbassi/gotop/src/termui"
@@ -15,7 +16,7 @@ type Mem struct {
 	interval time.Duration
 }
 
-func NewMem(interval time.Duration, horizontalScale int) *Mem {
+func NewMem(renderLock *sync.RWMutex, interval time.Duration, horizontalScale int) *Mem {
 	self := &Mem{
 		LineGraph: ui.NewLineGraph(),
 		interval:  interval,
@@ -30,7 +31,9 @@ func NewMem(interval time.Duration, horizontalScale int) *Mem {
 	go func() {
 		ticker := time.NewTicker(self.interval)
 		for range ticker.C {
+			renderLock.RLock()
 			self.update()
+			renderLock.RUnlock()
 		}
 	}()
 
diff --git a/src/widgets/net.go b/src/widgets/net.go
index 1a3c263..740e044 100644
--- a/src/widgets/net.go
+++ b/src/widgets/net.go
@@ -3,6 +3,7 @@ package widgets
 import (
 	"fmt"
 	"log"
+	"sync"
 	"time"
 
 	ui "github.com/cjbassi/gotop/src/termui"
@@ -18,7 +19,7 @@ type Net struct {
 	prevSentTotal uint64
 }
 
-func NewNet() *Net {
+func NewNet(renderLock *sync.RWMutex) *Net {
 	recv := ui.NewSparkline()
 	recv.Data = []int{0}
 
@@ -37,7 +38,9 @@ func NewNet() *Net {
 	go func() {
 		ticker := time.NewTicker(self.interval)
 		for range ticker.C {
+			renderLock.RLock()
 			self.update()
+			renderLock.RUnlock()
 		}
 	}()
 
diff --git a/src/widgets/proc.go b/src/widgets/proc.go
index f3dc441..69fd199 100644
--- a/src/widgets/proc.go
+++ b/src/widgets/proc.go
@@ -6,6 +6,7 @@ import (
 	"os/exec"
 	"sort"
 	"strconv"
+	"sync"
 	"time"
 
 	ui "github.com/cjbassi/gotop/src/termui"
@@ -38,7 +39,7 @@ type Proc struct {
 	group          bool
 }
 
-func NewProc() *Proc {
+func NewProc(renderLock *sync.RWMutex) *Proc {
 	cpuCount, err := psCPU.Counts(false)
 	if err != nil {
 		log.Printf("failed to get CPU count from gopsutil: %v", err)
@@ -66,9 +67,9 @@ func NewProc() *Proc {
 	go func() {
 		ticker := time.NewTicker(self.interval)
 		for range ticker.C {
-			self.Lock()
+			renderLock.RLock()
 			self.update()
-			self.Unlock()
+			renderLock.RUnlock()
 		}
 	}()
 
diff --git a/src/widgets/temp.go b/src/widgets/temp.go
index 9c1b2e9..76ef243 100644
--- a/src/widgets/temp.go
+++ b/src/widgets/temp.go
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"image"
 	"sort"
+	"sync"
 	"time"
 
 	ui "github.com/gizak/termui"
@@ -22,7 +23,7 @@ type Temp struct {
 	Fahrenheit bool
 }
 
-func NewTemp(fahrenheit bool) *Temp {
+func NewTemp(renderLock *sync.RWMutex, fahrenheit bool) *Temp {
 	self := &Temp{
 		Block:     ui.NewBlock(),
 		interval:  time.Second * 5,
@@ -41,7 +42,9 @@ func NewTemp(fahrenheit bool) *Temp {
 	go func() {
 		ticker := time.NewTicker(self.interval)
 		for range ticker.C {
+			renderLock.RLock()
 			self.update()
+			renderLock.RUnlock()
 		}
 	}()