updat

.gitignore

@@ -0,0 +1 @@
+.idea/

ast/main.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+)
+
+func main() {
+	fset := token.NewFileSet()
+	file, err := parser.ParseFile(fset, "../sync/pool/main.go", nil, parser.ParseComments)
+	if err != nil {
+		panic(err)
+	}
+	ast.Inspect(file, func(n ast.Node) bool {
+		funcCall, ok := n.(*ast.CallExpr)
+		if ok {
+			mthd, ok := funcCall.Fun.(*ast.SelectorExpr)
+			if ok {
+				fmt.Printf("mthd %+v\n", mthd)
+				id, ok := mthd.X.(*ast.Ident)
+				if ok {
+					if id.Name == "bufPool" {
+						line := fset.Position(mthd.Pos()).Line
+						fmt.Printf("line %v\n", line)
+						for _, cg := range file.Comments {
+							fmt.Printf("cg %v\n", cg.Text())
+						}
+					}
+				}
+			}
+		}
+		return true
+	})
+}

ioreader/main.go

@@ -0,0 +1,221 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"sync"
+)
+
+func main() {
+	//	runtime.GOMAXPROCS(2)
+	//	bytes_reader()
+	// tee_reader()
+	// multi_reader()
+	multi_writer()
+}
+
+func bytes_reader() {
+	f, err := os.Open("/Users/sean/Downloads/buildingapplicationonmesos.pdf")
+	if err != nil {
+		panic(err)
+	}
+	b, err := ioutil.ReadAll(f)
+	if err != nil {
+		panic(err)
+	}
+
+	r := bytes.NewReader(b)
+
+	data := make([]byte, 10)
+	_, err = r.Read(data)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Printf("data %+v\n", data)
+
+	// rewind to start
+	_, err = r.Seek(0, io.SeekStart)
+	if err != nil {
+		panic(err)
+	}
+
+	target, err := os.Create("./save")
+	if err != nil {
+		panic(err)
+	}
+	_, err = io.Copy(target, r)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func tmp_file() {
+
+	f, err := ioutil.TempFile("", "upload")
+	if err != nil {
+		panic(err)
+	}
+	defer func() {
+		n := f.Name()
+		f.Close()
+		os.Remove(n)
+	}()
+	s, err := os.Open("/Users/sean/Downloads/buildingapplicationonmesos.pdf")
+	if err != nil {
+		panic(err)
+	}
+	_, err = io.Copy(f, s)
+	if err != nil {
+		panic(err)
+	}
+	f.Seek(0, io.SeekStart)
+	processFileMeta(f)
+	// rewind to head
+	f.Seek(0, io.SeekStart)
+	handleFile(f)
+}
+
+func multi_reader() {
+	f, err := os.Open("/Users/sean/Downloads/buildingapplicationonmesos.pdf")
+	if err != nil {
+		panic(err)
+	}
+	b := make([]byte, 2)
+	_, err = f.Read(b)
+	if err != nil {
+		panic(err)
+	}
+	r := io.MultiReader(bytes.NewReader(b), f)
+	handleFile(r)
+}
+
+func tee_reader() {
+	f, err := os.Open("/Users/sean/Downloads/buildingapplicationonmesos.pdf")
+	if err != nil {
+		panic(err)
+	}
+
+	// create a pipe and tee reader
+	pr, pw := io.Pipe()
+	tr := io.TeeReader(f, pw)
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	go func() {
+		defer pw.Close()
+		defer wg.Done()
+		handleFile(tr)
+	}()
+
+	go func() {
+		defer wg.Done()
+		processFileMeta(pr)
+	}()
+
+	wg.Wait()
+}
+
+func multi_writer() {
+	f, err := os.Open("/Users/sean/Downloads/buildingapplicationonmesos.pdf")
+	if err != nil {
+		panic(err)
+	}
+	ar, aw := io.Pipe()
+	br, bw := io.Pipe()
+	cr, cw := io.Pipe()
+	dr, dw := io.Pipe()
+
+	var wg sync.WaitGroup
+	wg.Add(4)
+
+	go func() {
+		defer wg.Done()
+		handleFile(ar)
+	}()
+
+	go func() {
+		defer wg.Done()
+		handleFile1(br)
+	}()
+	go func() {
+		defer wg.Done()
+		handleFile2(cr)
+	}()
+	go func() {
+		defer wg.Done()
+		handleFile3(dr)
+	}()
+
+	go func() {
+		defer func() {
+			aw.Close()
+			bw.Close()
+			cw.Close()
+			dw.Close()
+		}()
+
+		mw := io.MultiWriter(aw, bw, cw, dw)
+		io.Copy(mw, f)
+	}()
+
+	wg.Wait()
+
+}
+
+func handleFile(r io.Reader) {
+	target, err := os.Create("./save")
+	if err != nil {
+		panic(err)
+	}
+	_, err = io.Copy(target, r)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func handleFile1(r io.Reader) {
+	target, err := os.Create("./save1")
+	if err != nil {
+		panic(err)
+	}
+	_, err = io.Copy(target, r)
+	if err != nil {
+		panic(err)
+	}
+}
+func handleFile2(r io.Reader) {
+	target, err := os.Create("./save2")
+	if err != nil {
+		panic(err)
+	}
+	_, err = io.Copy(target, r)
+	if err != nil {
+		panic(err)
+	}
+}
+func handleFile3(r io.Reader) {
+	target, err := os.Create("./save3")
+	if err != nil {
+		panic(err)
+	}
+	_, err = io.Copy(target, r)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func processFileMeta(r io.Reader) {
+	target, err := os.Create("./save_meta")
+	if err != nil {
+		panic(err)
+	}
+	_, err = io.Copy(target, r)
+	if err != nil {
+		panic(err)
+	}
+}