Add importer-skip-update marker (#60)

internal/cli/update_test.go

@@ -24,6 +24,10 @@ func TestUpdate(t *testing.T) {
 			inputFile: "../../testdata/markdown/import-with-exporter-before.md",
 			wantFile:  "../../testdata/markdown/import-with-exporter-updated.md",
 		},
+		"markdown with skip update": {
+			inputFile: "../../testdata/markdown/skip-update.md",
+			wantFile:  "../../testdata/markdown/skip-update.md",
+		},
 	}
 
 	for name, tc := range cases {

internal/file/file.go

@@ -23,4 +23,8 @@ type File struct {
 
 	// Markers is an array holding onto each annotation block.
 	Markers map[int]*marker.Marker
+
+	// SkipUpdate is used to skip updating the file in place. This is set by a
+	// special marker syntax.
+	SkipUpdate bool
 }

internal/file/replace.go

@@ -33,6 +33,13 @@ func (f *File) ReplaceWithAfter(options ...ReplaceOption) error {
 		opt(mode)
 	}
 
+	// If SkipUpdate flag is on, do not update the file.
+	if f.SkipUpdate {
+		// Perhaps it's more friendly to log that the file update is being
+		// skipped. If that's truly the case, handle it here.
+		mode.isDryRun = true
+	}
+
 	return replace(f.FileName, f.ContentAfter, mode)
 }
 

internal/file/replace_test.go

@@ -44,6 +44,18 @@ func TestReplaceWithAfter(t *testing.T) {
 			},
 			want: "", // not written
 		},
+		"skip-update found": {
+			input: &File{
+				FileName: "tmpfile.txt",
+				ContentBefore: []string{
+					"Some data",
+					"and more",
+				},
+				ContentAfter: []byte(`Completely different data`),
+				SkipUpdate:   true,
+			},
+			want: "", // not written
+		},
 	}
 
 	for name, tc := range cases {

internal/parse/parse.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"path/filepath"
+	"strings"
 
 	"github.com/upsidr/importer/internal/errorsplus"
 	"github.com/upsidr/importer/internal/file"
@@ -33,28 +34,37 @@ var (
 //
 // If any of the above steps failed, it would return an error. This function
 // does not populate the ContentAfter.
+//
+// TODO: Consider merging with the private parse method, as this public
+//       function is not adding any value at the moment.
 func Parse(fileName string, input io.Reader) (*file.File, error) {
 	if input == nil {
 		return nil, ErrNoInput
 	}
 
-	fileType := filepath.Ext(fileName)
+	return parse(fileName, input)
+}
+
+// parse reads file input using scanner. This reads the input line by line, and
+// store the data into File data. Parsing the data stores 3 sets of data: file
+// content as is, marker details, and file content with all data between
+// marker pairs purged.
+func parse(fileName string, input io.Reader) (*file.File, error) {
+	var importerMarkerRegex string
+	var importerSkipMarker string
 
+	fileType := filepath.Ext(fileName)
 	switch fileType {
 	case ".md":
-		return parse(marker.ImporterMarkerMarkdown, fileName, input)
+		importerMarkerRegex = marker.ImporterMarkerMarkdown
+		importerSkipMarker = marker.ImporterSkipProcessingMarkdown
 	case ".yaml", ".yml":
-		return parse(marker.ImporterMarkerYAML, fileName, input)
+		importerMarkerRegex = marker.ImporterMarkerYAML
+		importerSkipMarker = marker.ImporterSkipProcessingYAML
 	default:
 		return nil, fmt.Errorf("%w, '%s' provided", ErrUnsupportedFileType, fileType)
 	}
-}
 
-// parse reads file input using scanner. This reads the input line by line, and
-// store the data into File data. Parsing the data stores 3 sets of data: file
-// content as is, marker details, and file content with all data between
-// marker pairs purged.
-func parse(markerRegex string, fileName string, input io.Reader) (*file.File, error) {
 	f := &file.File{
 		FileName: fileName,
 
@@ -80,8 +90,14 @@ func parse(markerRegex string, fileName string, input io.Reader) (*file.File, er
 		currentStr := scanner.Text()
 		f.ContentBefore = append(f.ContentBefore, currentStr)
 
+		// If skip marker is found, turn on the flag. This flag should disable
+		// in-place file update, but should not suppress generate or preview.
+		if strings.Contains(currentStr, importerSkipMarker) {
+			f.SkipUpdate = true
+		}
+
 		// Look for marker match
-		matches, err := regexpplus.MapWithNamedSubgroups(currentStr, markerRegex)
+		matches, err := regexpplus.MapWithNamedSubgroups(currentStr, importerMarkerRegex)
 		if err != nil {
 			if errors.Is(err, regexpplus.ErrNoMatch) {
 				// If the line appears within some other marker set, remove the line.

testdata/markdown/skip-update.md

@@ -0,0 +1,7 @@
+<!-- == importer-skip-update == -->
+# Markdown Demo
+
+<!-- == imptr: short-description / begin from: ./snippet-description.md#[for-demo] == -->
+This part will not be deleted, because of the "importer-skip-update" marker at the top of the file.
+This is useful for some files that use Importer Markers as "template", and use "importer generate" to generate a separate file.
+<!-- == imptr: short-description / end == -->

testdata/yaml/skip-update.yaml

@@ -0,0 +1,6 @@
+# == importer-skip-update ==
+
+title: Demo of YAML Importer
+# == import: description / begin from: ./snippet-description.yaml#[for-demo] ==
+dummy: This data will NOT be removed
+# == import: description / end ==