fix: windows enhancements (#110)

* use filepath to check for known packages

this fixes an issue using windows. without this patch, jb would delete
the folder after installation since the path is not known

* reduce temp directory length by hashing

using this hash it is harder to reach the windows limit for filenames
and directories

* further reduce temp dir length

* do not build binaries for windows/amd*

Makefile

@@ -18,6 +18,7 @@ cross: clean
 	  -ldflags=$(LDFLAGS) \
 	  -arch="amd64 arm64 arm" -os="linux" \
 	  -osarch="darwin/amd64" \
+	  -osarch="windows/amd64" \
 	  ./cmd/$(BIN)
 
 static:

pkg/git.go

@@ -19,6 +19,8 @@ import (
 	"bytes"
 	"compress/gzip"
 	"context"
+	"crypto/sha256"
+	"encoding/hex"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -176,7 +178,9 @@ func remoteResolveRef(ctx context.Context, remote string, ref string) (string, e
 func (p *GitPackage) Install(ctx context.Context, name, dir, version string) (string, error) {
 	destPath := path.Join(dir, name)
 
-	tmpDir, err := ioutil.TempDir(filepath.Join(dir, ".tmp"), fmt.Sprintf("jsonnetpkg-%s-%s", strings.Replace(name, "/", "-", -1), version))
+	pkgh := sha256.Sum256([]byte(fmt.Sprintf("jsonnetpkg-%s-%s", strings.Replace(name, "/", "-", -1), version)))
+	// using 16 bytes should be a good middle ground between length and collision resistance
+	tmpDir, err := ioutil.TempDir(filepath.Join(dir, ".tmp"), hex.EncodeToString(pkgh[:16]))
 	if err != nil {
 		return "", errors.Wrap(err, "failed to create tmp dir")
 	}

pkg/packages.go

@@ -200,6 +200,7 @@ func checkLegacyNameTaken(legacyName string, pkgName string) (bool, error) {
 }
 
 func known(deps map[string]deps.Dependency, p string) bool {
+	p = filepath.ToSlash(p)
 	for _, d := range deps {
 		k := d.Name()
 		if strings.HasPrefix(p, k) || strings.HasPrefix(k, p) {