app: add examples for egg command (#77)

.gitignore

@@ -5,7 +5,8 @@
 *.img
 *.hdd
 
-eggos.iso
+*.iso
+egg
 bootblock
 serial
 trace.txt

README.md

@@ -84,6 +84,8 @@ Run `egg build -o kernel.elf` in your project directory to get the kernel file,
 
 `egg pack -o eggos.iso -k kernel.elf` can pack the kernel into an iso file, and then you can use https://github.com/ventoy/Ventoy to run the iso file on a bare metal.
 
+Here are some examples [examples](./app/examples)
+
 Happy hacking!
 
 # Debug

README_CN.md

@@ -83,6 +83,8 @@ $ mage qemu
 
 `egg pack -o eggos.iso -k kernel.elf` 可以将内核打包成一个iso文件，通过 https://github.com/ventoy/Ventoy 即可运行在真实的机器上。
 
+这里是一些例子[例子](./app/examples)
+
 Happy hacking!
 
 # Debug

app/examples/README.md

@@ -0,0 +1,50 @@
+This directory contains examples of how `eggos` can be used to write common go applications.
+
+# helloworld
+
+``` sh
+$ cd helloworld
+$ egg run
+```
+
+# concurrent prime sieve
+
+``` sh
+$ cd prime-sieve
+$ egg run
+```
+
+# http server
+
+``` sh
+$ cd httpd
+$ egg run -p 8000:8000
+```
+
+Access this address from browser http://127.0.0.1:8000/hello
+
+# simple repl program
+
+``` sh
+$ cd repl
+$ egg run
+```
+
+# simple animation
+
+Code from `The Go Programming Language`
+
+``` sh
+$ cd graphic
+$ egg pack -o graphic.iso
+$ egg run graphic.iso
+```
+
+# handle syscall
+
+This example shows how to add or modify syscall
+
+``` sh
+$ cd syscall
+$ egg run
+```

app/examples/graphic/main.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+	"math"
+	"math/rand"
+	"time"
+
+	"github.com/icexin/eggos/drivers/vbe"
+)
+
+var palette = []color.Color{color.White, color.Black}
+
+const (
+	whiteIndex = 0 // first color in palette
+	blackIndex = 1 // next color in palette
+)
+
+func main() {
+	// The sequence of images is deterministic unless we seed
+	// the pseudo-random number generator using the current time.
+	// Thanks to Randall McPherson for pointing out the omission.
+	rand.Seed(time.Now().UTC().UnixNano())
+	canvas := vbe.DefaultView.Canvas()
+	lissajous(canvas)
+}
+
+func lissajous(canvas draw.Image) {
+	const (
+		cycles  = 5     // number of complete x oscillator revolutions
+		res     = 0.001 // angular resolution
+		size    = 100   // image canvas covers [-size..+size]
+		nframes = 64    // number of animation frames
+		delay   = 8     // delay between frames in 10ms units
+	)
+
+	freq := rand.Float64() * 3.0 // relative frequency of y oscillator
+	phase := 0.0                 // phase difference
+	for {
+		rect := image.Rect(0, 0, 2*size+1, 2*size+1)
+		img := image.NewPaletted(rect, palette)
+		for t := 0.0; t < cycles*2*math.Pi; t += res {
+			x := math.Sin(t)
+			y := math.Sin(t*freq + phase)
+			img.SetColorIndex(size+int(x*size+0.5), size+int(y*size+0.5),
+				blackIndex)
+		}
+		phase += 0.1
+		time.Sleep(time.Duration(delay*10) * time.Millisecond)
+		draw.Draw(canvas, img.Rect, img, image.ZP, draw.Src)
+		vbe.DefaultView.CommitRect(img.Rect)
+	}
+}

app/examples/helloworld/main.go

@@ -0,0 +1,7 @@
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("hello eggos")
+}

app/examples/httpd/main.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+)
+
+func main() {
+	http.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) {
+		io.WriteString(w, "hello eggos")
+	})
+	fmt.Println("http server listen on :8000")
+	http.ListenAndServe(":8000", nil)
+}

app/examples/prime-sieve/main.go

@@ -0,0 +1,36 @@
+// A concurrent prime sieve
+
+package main
+
+import "fmt"
+
+// Send the sequence 2, 3, 4, ... to channel 'ch'.
+func Generate(ch chan<- int) {
+	for i := 2; ; i++ {
+		ch <- i // Send 'i' to channel 'ch'.
+	}
+}
+
+// Copy the values from channel 'in' to channel 'out',
+// removing those divisible by 'prime'.
+func Filter(in <-chan int, out chan<- int, prime int) {
+	for {
+		i := <-in // Receive value from 'in'.
+		if i%prime != 0 {
+			out <- i // Send 'i' to 'out'.
+		}
+	}
+}
+
+// The prime sieve: Daisy-chain Filter processes.
+func main() {
+	ch := make(chan int) // Create a new channel.
+	go Generate(ch)      // Launch Generate goroutine.
+	for i := 0; i < 10; i++ {
+		prime := <-ch
+		fmt.Println(prime)
+		ch1 := make(chan int)
+		go Filter(ch, ch1, prime)
+		ch = ch1
+	}
+}

app/examples/repl/main.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"crypto/sha1"
+	"fmt"
+)
+
+func main() {
+	var s string
+	for {
+		fmt.Print(">>> ")
+		fmt.Scan(&s)
+		sum := sha1.Sum([]byte(s))
+		fmt.Printf("sha1(%s) = %x\n", s, sum)
+	}
+}

app/examples/syscall/main.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+
+	"github.com/icexin/eggos/kernel/isyscall"
+)
+
+var handler isyscall.Handler
+
+func handleUname(req *isyscall.Request) {
+	fmt.Println("syscall `uname` called")
+	handler(req)
+}
+
+func main() {
+	handler = isyscall.GetHandler(syscall.SYS_UNAME)
+	isyscall.Register(syscall.SYS_UNAME, handleUname)
+	_, err := os.Hostname()
+	if err != nil {
+		panic(err)
+	}
+}