Kadai3-2-manhdaovan download tool

.gitignore

@@ -0,0 +1,5 @@
+kadai3-1/manhdaovan/vendor
+cover.out
+kadai3-2/manhdaovan/vendor
+vendor
+kadai3-2/manhdaovan/tmp

go.mod

@@ -0,0 +1,9 @@
+module github.com/gopherdojo/dojo5
+
+go 1.12
+
+require (
+	github.com/pkg/errors v0.8.0
+	golang.org/x/net v0.0.0-20190619014844-b5b0513f8c1b
+	golang.org/x/sync v0.0.0-20190423024810-112230192c58
+)

go.sum

@@ -0,0 +1,9 @@
+github.com/pkg/errors v0.8.0 h1:WdK/asTD0HN+q6hsWO3/vpuAkAr+tw6aNJNDFFf0+qw=
+github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20190619014844-b5b0513f8c1b h1:lkjdUzSyJ5P1+eal9fxXX9Xg2BTfswsonKUse48C0uE=
+golang.org/x/net v0.0.0-20190619014844-b5b0513f8c1b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

kadai3-2/manhdaovan/Makefile

@@ -0,0 +1,13 @@
+COVERAGE_VIEW_MODE=html# or "func"
+GOMOD=on#or "off" or "auto"
+
+install:
+	- GO111MODULE=${GOMOD} go mod vendor
+	- GO111MODULE=${GOMOD} go mod tidy
+build: ./cmd/main.go
+	- GO111MODULE=${GOMOD} go build -a -o ./bin/mget ./cmd/main.go
+test: ./pkg/mget/mget_test.go
+	- GO111MODULE=${GOMOD} go test -a -race ./pkg/...
+coverage: test
+	- GO111MODULE=${GOMOD} go test -coverprofile=cover.out ./...
+	- GO111MODULE=${GOMOD} go tool cover -${COVERAGE_VIEW_MODE} cover.out 

kadai3-2/manhdaovan/cmd/main.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"net/http"
+	"os"
+	"runtime"
+
+	"github.com/gopherdojo/dojo5/kadai3-2/manhdaovan/pkg/mget"
+)
+
+const (
+	exitErr = 1
+)
+
+func main() {
+	ca := parseArgs()
+	if err := ca.validate(); err != nil {
+		fmt.Fprintln(os.Stderr, "given args error: ", err)
+		printHelp()
+		os.Exit(exitErr)
+	}
+	if _, err := os.Stat(ca.outPath); err != nil {
+		fmt.Fprintf(os.Stderr, "invalid output path: %s, err: %+v\n", ca.outPath, err)
+		printHelp()
+		os.Exit(exitErr)
+	}
+
+	downloader := mget.NewMGet(http.DefaultClient, ca.numWorkers, mget.DefaultExitSigs, "", "")
+	outputPath, err := downloader.Download(context.Background(), ca.outPath, ca.url)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "download error: %+v\n", err)
+		printHelp()
+		os.Exit(exitErr)
+	}
+
+	fmt.Println("Download completed. Output: ", outputPath)
+}
+
+type cliArgs struct {
+	numWorkers uint
+	outPath    string
+	url        string
+}
+
+func (ca *cliArgs) validate() error {
+	if ca.numWorkers == 0 {
+		return fmt.Errorf("number worker must be greater than 0")
+	}
+	if ca.url == "" {
+		return fmt.Errorf("no download url given")
+	}
+
+	if ca.outPath == "" {
+		ca.outPath = "./out/"
+	}
+
+	return nil
+}
+
+func parseArgs() *cliArgs {
+	var ca cliArgs
+	flag.UintVar(&ca.numWorkers, "w", uint(runtime.NumCPU()), "number of workers")
+	flag.StringVar(&ca.outPath, "o", "", "output file path")
+	flag.Parse()
+	ca.url = flag.Arg(0) // last arg is download url
+
+	return &ca
+}
+
+func printHelp() {
+	helpStr := `
+mget -- a simple concurrency download tool
+usage: $./bin/mget [-w] [-o] download-url
+options:
+	-w unit
+	    Number of workers that download in concurrent
+	-o string
+		Output of downloaded file. It can be a directory or a file path.
+`
+	fmt.Println(helpStr)
+}

kadai3-2/manhdaovan/out/.gitignore

@@ -0,0 +1,2 @@
+*/*
+*

kadai3-2/manhdaovan/pkg/mget/chunk.go

@@ -0,0 +1,34 @@
+package mget
+
+import (
+	"fmt"
+	"path/filepath"
+)
+
+type chunkInfo struct {
+	idx       int
+	url       string
+	size      uint64
+	rangeLow  uint64
+	rangeHigh uint64
+}
+
+func newChunkInfo(idx int, url string, fileSize, chunkSize uint64) *chunkInfo {
+	offset := uint64(idx) * chunkSize
+	if offset+chunkSize > fileSize { // last chunk
+		chunkSize = fileSize - offset
+	}
+
+	return &chunkInfo{
+		idx:       idx,
+		url:       url,
+		size:      chunkSize,
+		rangeLow:  offset,
+		rangeHigh: offset + chunkSize - 1,
+	}
+}
+
+func chunkPath(dstDir, dstFile string, idx int) string {
+	chunkName := fmt.Sprintf("%s-%d.chunk", dstFile, idx)
+	return filepath.Join(dstDir, chunkName)
+}

kadai3-2/manhdaovan/pkg/mget/file.go

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+package mget
+
+import (
+	"path/filepath"
+	"strings"
+)
+
+// parseDirAndFileName returns dir path and file name from given path
+func parseDirAndFileName(path string) (dir, file string) {
+	lastSlashIdx := strings.LastIndex(path, "/")
+	dir = path[:lastSlashIdx+1]
+	if len(dir) == len(path) { // path is a dir
+		return dir, ""
+	}
+
+	return dir, path[(len(dir) + 1):]
+}
+
+// parseFileName returns file name from given url
+func parseFileName(url string) string {
+	return filepath.Base(url)
+}