478 identify go binaries and extract mod information (#534)

* add query by MIME type to source.FileResolver

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* import stereoscope lib changes to find mime type

- add bin cataloger
- add bin parser
- add mime type go utils
- import new resolver

Signed-off-by: Christopher Angelo Phillips <christopher.phillips@anchore.com>

* add go std library code to unpack bin

- keep them in their own (original) files
- add note for "this code was copied from"
- comment the lines the required changing

Signed-off-by: Christopher Angelo Phillips <christopher.phillips@anchore.com>
Co-authored-by: Alex Goodman <alex.goodman@anchore.com>

syft/pkg/cataloger/golang/parse_go_bin.go

@@ -0,0 +1,63 @@
+package golang
+
+import (
+	"bufio"
+	"io"
+	"strings"
+
+	"github.com/anchore/syft/syft/pkg"
+	"github.com/anchore/syft/syft/source"
+)
+
+const (
+	packageIdentifier = "dep"
+	replaceIdentifier = "=>"
+)
+
+func parseGoBin(path string, reader io.ReadCloser) ([]pkg.Package, error) {
+	// Identify if bin was compiled by go
+	x, err := openExe(reader)
+	if err != nil {
+		return nil, err
+	}
+
+	_, mod := findVers(x)
+
+	pkgs := buildGoPkgInfo(path, mod)
+
+	return pkgs, nil
+}
+
+func buildGoPkgInfo(path, mod string) []pkg.Package {
+	pkgsSlice := make([]pkg.Package, 0)
+	scanner := bufio.NewScanner(strings.NewReader(mod))
+
+	// filter mod dependencies: [dep, name, version, sha]
+	for scanner.Scan() {
+		fields := strings.Fields(scanner.Text())
+		// must have dep, name, version
+		if len(fields) < 3 {
+			continue
+		}
+		switch fields[0] {
+		case packageIdentifier:
+			pkgsSlice = append(pkgsSlice, pkg.Package{
+				Name:     fields[1],
+				Version:  fields[2],
+				Language: pkg.Go,
+				Type:     pkg.GoModulePkg,
+				Locations: []source.Location{
+					{
+						RealPath: path,
+					},
+				},
+			})
+		case replaceIdentifier:
+			pkg := &pkgsSlice[len(pkgsSlice)-1]
+			pkg.Name = fields[1]
+			pkg.Version = fields[2]
+		}
+	}
+
+	return pkgsSlice
+}