small reorganization

Signed-off-by: egibs <20933572+egibs@users.noreply.github.com>

Author: egibs

pkg/action/scan.go

@@ -76,12 +76,6 @@ func scanSinglePath(ctx context.Context, c malcontent.Config, path string, ruleF
 		return fr, nil
 	}
 
-	initReadPool.Do(func() {
-		readPool = pool.NewBufferPool(runtime.GOMAXPROCS(0))
-	})
-	// create a buffer sized to the minimum of the file's size or the default ReadBuffer
-	buf := readPool.Get(min(size, file.ReadBuffer)) //nolint:nilaway // the buffer pool is created above
-
 	mime := "<unknown>"
 	kind, err := programkind.File(ctx, path)
 	if err != nil && !interactive(c) {
@@ -137,6 +131,14 @@ func scanSinglePath(ctx context.Context, c malcontent.Config, path string, ruleF
 		return fr, nil
 	}
 
+	initReadPool.Do(func() {
+		readPool = pool.NewBufferPool(runtime.GOMAXPROCS(0))
+	})
+
+	// create a buffer sized to the minimum of the file's size or the default ReadBuffer
+	// only do so if we actually need to retrieve the file's contents
+	buf := readPool.Get(min(size, file.ReadBuffer)) //nolint:nilaway // the buffer pool is created above
+
 	// Only retrieve the file's contents and calculate its checksum if we need to generate a report
 	fc, err := file.GetContents(f, buf)
 	if err != nil {

pkg/programkind/programkind.go

@@ -252,28 +252,24 @@ func File(ctx context.Context, path string) (*FileType, error) {
 		return nil, fmt.Errorf("stat: %w", err)
 	}
 
-	if st.IsDir() {
+	// ignore directories, irregular files, and empty files
+	if st.IsDir() || st.Mode().Type() == fs.ModeIrregular || st.Size() == 0 {
 		return nil, nil
 	}
-	if st.Mode().Type() == fs.ModeIrregular {
-		return nil, nil
-	}
-	if st.Size() == 0 {
-		return nil, nil
+
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("open: %w", err)
 	}
+	defer f.Close()
 
+	// initialize the header pool after we've successfully opened the file
 	initializeHeaderPool()
 
 	// create a buffer sized to the minimum of the file's size or the default ReadBuffer
 	buf := headerPool.Get(min(st.Size(), file.ReadBuffer)) //nolint:nilaway // the buffer pool is created above
 	defer headerPool.Put(buf)
 
-	f, err := os.Open(path)
-	if err != nil {
-		return nil, fmt.Errorf("open: %w", err)
-	}
-	defer f.Close()
-
 	fc, err := file.GetContents(f, buf)
 	if err != nil {
 		return nil, fmt.Errorf("file contents: %w", err)