internal/postgres: factor out symbol history collect

For golang/go#37102

Change-Id: Ie2faa956e3ecb54ef00c197174cc9f16f15a8d2e
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/316989
Trust: Julie Qiu <julie@golang.org>
Run-TryBot: Julie Qiu <julie@golang.org>
Reviewed-by: Jonathan Amsterdam <jba@google.com>

internal/postgres/package_symbol.go

@@ -47,11 +47,23 @@ func getPackageSymbols(ctx context.Context, ddb *database.DB, packagePath, modul
 			CASE WHEN ps.type='Type' THEN 0 ELSE 1 END,
 			symbol_name;`
 
-	// versionToNameToUnitSymbol contains all of the types for this unit,
-	// grouped by name and build context. This is used to keep track of the
-	// parent types, so that we can map the children to those symbols.
+	sh, collect := collectSymbolHistory(func(sh *internal.SymbolHistory, sm internal.SymbolMeta, v string, build internal.BuildContext) error {
+		if sm.Section == internal.SymbolSectionTypes && sm.Kind != internal.SymbolKindType {
+			_, err := sh.GetSymbol(sm.ParentName, v, build)
+			return err
+		}
+		return nil
+	})
+	if err := ddb.RunQuery(ctx, query, collect, packagePath, modulePath); err != nil {
+		return nil, err
+	}
+	return sh, nil
+}
+
+func collectSymbolHistory(check func(sh *internal.SymbolHistory, sm internal.SymbolMeta, v string, build internal.BuildContext) error) (*internal.SymbolHistory, func(rows *sql.Rows) error) {
 	sh := internal.NewSymbolHistory()
-	collect := func(rows *sql.Rows) error {
+	return sh, func(rows *sql.Rows) (err error) {
+		defer derrors.Wrap(&err, "collectSymbolHistory")
 		var (
 			sm    internal.SymbolMeta
 			build internal.BuildContext
@@ -69,18 +81,12 @@ func getPackageSymbols(ctx context.Context, ddb *database.DB, packagePath, modul
 		); err != nil {
 			return fmt.Errorf("row.Scan(): %v", err)
 		}
-		if sm.Section == internal.SymbolSectionTypes && sm.Kind != internal.SymbolKindType {
-			if _, err := sh.GetSymbol(sm.ParentName, v, build); err != nil {
-				return err
-			}
+		if err := check(sh, sm, v, build); err != nil {
+			return fmt.Errorf("check(): %v", err)
 		}
 		sh.AddSymbol(sm, v, build)
 		return nil
 	}
-	if err := ddb.RunQuery(ctx, query, collect, packagePath, modulePath); err != nil {
-		return nil, err
-	}
-	return sh, nil
 }
 
 // legacyGetPackageSymbols returns all of the symbols for a given package path and module path.

internal/postgres/symbol_history.go

@@ -60,30 +60,7 @@ func GetSymbolHistoryFromTable(ctx context.Context, ddb *database.DB,
 		return nil, err
 	}
 
-	// versionToNameToUnitSymbol is a map of the version a symbol was
-	// introduced, to the name and unit symbol.
-	sh := internal.NewSymbolHistory()
-	collect := func(rows *sql.Rows) error {
-		var (
-			sm    internal.SymbolMeta
-			build internal.BuildContext
-			v     string
-		)
-		if err := rows.Scan(
-			&sm.Name,
-			&sm.ParentName,
-			&sm.Section,
-			&sm.Kind,
-			&sm.Synopsis,
-			&v,
-			&build.GOOS,
-			&build.GOARCH,
-		); err != nil {
-			return fmt.Errorf("row.Scan(): %v", err)
-		}
-		sh.AddSymbol(sm, v, build)
-		return nil
-	}
+	sh, collect := collectSymbolHistory(func(*internal.SymbolHistory, internal.SymbolMeta, string, internal.BuildContext) error { return nil })
 	if err := ddb.RunQuery(ctx, query, collect, args...); err != nil {
 		return nil, err
 	}
@@ -126,7 +103,7 @@ func (db *DB) LegacyGetSymbolHistory(ctx context.Context, packagePath, modulePat
 // LegacyGetSymbolHistoryFromTable is exported for use in tests.
 func LegacyGetSymbolHistoryFromTable(ctx context.Context, ddb *database.DB,
 	packagePath, modulePath string) (_ map[string]map[string]*internal.UnitSymbol, err error) {
-	defer derrors.WrapStack(&err, "GetSymbolHistoryFromTable(ctx, ddb, %q, %q)", packagePath, modulePath)
+	defer derrors.WrapStack(&err, "LegacyGetSymbolHistoryFromTable(ctx, ddb, %q, %q)", packagePath, modulePath)
 
 	q := squirrel.Select(
 		"s1.name AS symbol_name",