[chore] Add some doc comments to source manager (#2434)

pkg/sources/source_manager.go

@@ -16,6 +16,8 @@ import (
 	"github.com/trufflesecurity/trufflehog/v3/pkg/pb/sourcespb"
 )
 
+// SourceManager provides an interface for starting and managing running
+// sources.
 type SourceManager struct {
 	api   apiClient
 	hooks []JobProgressHook
@@ -49,6 +51,8 @@ func WithAPI(api apiClient) func(*SourceManager) {
 	return func(mgr *SourceManager) { mgr.api = api }
 }
 
+// WithReportHook adds a hook to the SourceManager's reporting feature for
+// customizing data aggregation.
 func WithReportHook(hook JobProgressHook) func(*SourceManager) {
 	return func(mgr *SourceManager) {
 		mgr.hooks = append(mgr.hooks, hook)
@@ -82,6 +86,10 @@ func WithSourceUnits() func(*SourceManager) {
 	}
 }
 
+// WithSourceUnitsFunc dynamically configures whether to use source unit
+// enumeration and chunking if the source supports it. If the function returns
+// true and the source supports it, then units will be used. Otherwise, the
+// legacy scanning method will be used.
 func WithSourceUnitsFunc(f func() bool) func(*SourceManager) {
 	return func(mgr *SourceManager) { mgr.useSourceUnitsFunc = f }
 }
@@ -394,33 +402,45 @@ func (api *headlessAPI) GetIDs(context.Context, string, sourcespb.SourceType) (S
 }
 
 // mgrUnitReporter implements the UnitReporter interface.
+var _ UnitReporter = (*mgrUnitReporter)(nil)
+
 type mgrUnitReporter struct {
 	unitCh chan SourceUnit
 	report *JobProgress
 }
 
+// UnitOk implements the UnitReporter interface by recording the unit in the
+// report and sending it on the SourceUnit channel.
 func (s *mgrUnitReporter) UnitOk(ctx context.Context, unit SourceUnit) error {
 	s.report.ReportUnit(unit)
 	return common.CancellableWrite(ctx, s.unitCh, unit)
 }
 
+// UnitErr implements the UnitReporter interface by recording the error in the
+// report.
 func (s *mgrUnitReporter) UnitErr(ctx context.Context, err error) error {
 	s.report.ReportError(err)
 	return nil
 }
 
 // mgrChunkReporter implements the ChunkReporter interface.
+var _ ChunkReporter = (*mgrChunkReporter)(nil)
+
 type mgrChunkReporter struct {
 	unit    SourceUnit
 	chunkCh chan *Chunk
 	report  *JobProgress
 }
 
+// ChunkOk implements the ChunkReporter interface by recording the chunk and
+// its associated unit in the report and sending it on the Chunk channel.
 func (s *mgrChunkReporter) ChunkOk(ctx context.Context, chunk Chunk) error {
 	s.report.ReportChunk(s.unit, &chunk)
 	return common.CancellableWrite(ctx, s.chunkCh, &chunk)
 }
 
+// ChunkErr implements the ChunkReporter interface by recording the error and
+// its associated unit in the report.
 func (s *mgrChunkReporter) ChunkErr(ctx context.Context, err error) error {
 	s.report.ReportError(ChunkError{s.unit, err})
 	return nil