improve doc comments

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

internal/file/glob_match.go

@@ -1,5 +1,6 @@
 package file
 
+// GlobMatch evaluates the given glob pattern against the given "name" string, indicating if there is a match or not.
 // Source: https://research.swtch.com/glob.go
 func GlobMatch(pattern, name string) bool {
 	px := 0

internal/file/opener.go

@@ -5,10 +5,12 @@ import (
 	"os"
 )
 
+// Opener is an object that stores a path to later be opened as a file.
 type Opener struct {
 	path string
 }
 
+// Open the stored path as a io.ReadCloser.
 func (o Opener) Open() (io.ReadCloser, error) {
 	return os.Open(o.path)
 }

internal/file/zip_file_manifest.go

@@ -12,16 +12,20 @@ import (
 	"github.com/anchore/syft/internal/log"
 )
 
+// ZipFileManifest is a collection of paths and their file metadata.
 type ZipFileManifest map[string]os.FileInfo
 
+// newZipManifest creates an empty ZipFileManifest.
 func newZipManifest() ZipFileManifest {
 	return make(ZipFileManifest)
 }
 
+// Add a new path and it's file metadata to the collection.
 func (z ZipFileManifest) Add(entry string, info os.FileInfo) {
 	z[entry] = info
 }
 
+// GlobMatch returns the path keys that match the given value(s).
 func (z ZipFileManifest) GlobMatch(patterns ...string) []string {
 	uniqueMatches := internal.NewStringSet()
 
@@ -43,6 +47,7 @@ func (z ZipFileManifest) GlobMatch(patterns ...string) []string {
 	return results
 }
 
+// NewZipFileManifest creates and returns a new ZipFileManifest populated with path and metadata from the given zip archive path.
 func NewZipFileManifest(archivePath string) (ZipFileManifest, error) {
 	zipReader, err := zip.OpenReader(archivePath)
 	manifest := newZipManifest()
@@ -62,6 +67,7 @@ func NewZipFileManifest(archivePath string) (ZipFileManifest, error) {
 	return manifest, nil
 }
 
+// normalizeZipEntryName takes the given path entry and ensures it is prefixed with "/".
 func normalizeZipEntryName(entry string) string {
 	if !strings.HasPrefix(entry, "/") {
 		return "/" + entry

internal/file/zip_file_traversal.go

@@ -15,6 +15,7 @@ import (
 )
 
 const (
+	// represents the order of bytes
 	_  = iota
 	KB = 1 << (10 * iota)
 	MB
@@ -33,6 +34,7 @@ func newZipTraverseRequest(paths ...string) zipTraversalRequest {
 	return results
 }
 
+// TraverseFilesInZip enumerates all paths stored within a zip archive using the visitor pattern.
 func TraverseFilesInZip(archivePath string, visitor func(*zip.File) error, paths ...string) error {
 	request := newZipTraverseRequest(paths...)
 
@@ -63,6 +65,7 @@ func TraverseFilesInZip(archivePath string, visitor func(*zip.File) error, paths
 	return nil
 }
 
+// ExtractFromZipToUniqueTempFile extracts select paths for the given archive to a temporary directory, returning file openers for each file extracted.
 func ExtractFromZipToUniqueTempFile(archivePath, dir string, paths ...string) (map[string]Opener, error) {
 	results := make(map[string]Opener)
 
@@ -121,6 +124,7 @@ func ExtractFromZipToUniqueTempFile(archivePath, dir string, paths ...string) (m
 	return results, TraverseFilesInZip(archivePath, visitor, paths...)
 }
 
+// ContentsFromZip extracts select paths for the given archive and returns a set of string contents for each path.
 func ContentsFromZip(archivePath string, paths ...string) (map[string]string, error) {
 	results := make(map[string]string)
 
@@ -162,6 +166,7 @@ func ContentsFromZip(archivePath string, paths ...string) (map[string]string, er
 	return results, TraverseFilesInZip(archivePath, visitor, paths...)
 }
 
+// UnzipToDir extracts a zip archive to a target directory.
 func UnzipToDir(archivePath, targetDir string) error {
 	visitor := func(file *zip.File) error {
 		// the zip-slip attack protection is still being erroneously detected