Prepare package cache in advance (#84)

prepara cache

pkg/parser/parser.go

@@ -41,6 +41,11 @@ type Parser struct {
 
 // Parse parses cover profiles into statements, and modify their state based on git changes.
 func (parser *Parser) Parse(changes []*gittool.Change) (Packages, error) {
+	if err := parser.buildPackageCache(); err != nil {
+		parser.logger.WithError(err).Error("build package cache")
+		return nil, err
+	}
+
 	var result Packages
 
 	for _, coverProfile := range parser.coverProfileFiles {
@@ -65,6 +70,34 @@ func (parser *Parser) Parse(changes []*gittool.Change) (Packages, error) {
 	return result, nil
 }
 
+func (parser *Parser) buildPackageCache() error {
+
+	for _, coverFile := range parser.coverProfileFiles {
+		profiles, err := cover.ParseProfiles(coverFile)
+		if err != nil {
+			return err
+		}
+
+		for _, profile := range profiles {
+			dir, _ := filepath.Split(profile.FileName)
+			if dir != "" {
+				dir = strings.TrimSuffix(dir, "/")
+			}
+			_, ok := parser.packagesCache[dir]
+			if !ok {
+				pkg, err := build.Import(dir, ".", build.FindOnly)
+				if err != nil {
+					return err
+				}
+				parser.packagesCache[dir] = pkg
+				parser.packages[pkg.ImportPath] = &Package{Name: pkg.ImportPath}
+			}
+		}
+	}
+
+	return nil
+}
+
 // wrapper for Statement
 type statement struct {
 	*Statement
@@ -183,11 +216,7 @@ func findFile(packages packagesCache, file string) (filename, pkgpath string, er
 	}
 	pkg, ok := packages[dir]
 	if !ok {
-		pkg, err = build.Import(dir, ".", build.FindOnly)
-		if err != nil {
-			return "", "", fmt.Errorf("can't find %q: %w", file, err)
-		}
-		packages[dir] = pkg
+		return "", "", fmt.Errorf("no package found for %s", file)
 	}
 
 	return filepath.Join(pkg.Dir, file), pkg.ImportPath, nil
@@ -408,11 +437,11 @@ func isCodeLine(line string) bool {
 // It sort statements by startline first, then try to find first statement
 // that line number is greater than or equals the startline of the statement.
 // There are two edge cases:
-// 1. When line number is less than all the statements, `Search` function will return 0,
-//    but there is no suitable statement, should return immediately.
-// 2. Otherwise, `Search` function will return first statement that its startline is greater than changed line number,
-//    then statement of that position minus one is the statement we want,
-//    but still need to check whether the changed line is among the statement scope.
+//  1. When line number is less than all the statements, `Search` function will return 0,
+//     but there is no suitable statement, should return immediately.
+//  2. Otherwise, `Search` function will return first statement that its startline is greater than changed line number,
+//     then statement of that position minus one is the statement we want,
+//     but still need to check whether the changed line is among the statement scope.
 func (parser *Parser) setStatementsStateByLineNumber(changedlineNumber int, statements []*statement) {
 	idx := sort.Search(len(statements), func(i int) bool {
 		return statements[i].startLine > changedlineNumber

pkg/parser/parser_test.go

@@ -7,6 +7,36 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+func TestParser(t *testing.T) {
+	t.Run("buildPackageCache", func(t *testing.T) {
+		parser := &Parser{
+			coverProfileFiles: []string{"testdata/cover.out"},
+			packages:          make(map[string]*Package),
+			packagesCache:     make(packagesCache),
+			logger:            logrus.New(),
+		}
+
+		parser.buildPackageCache()
+		for _, pkg := range []string{
+			"github.com/Azure/gocover/pkg/parser",
+			"github.com/Azure/gocover/pkg/report",
+			"github.com/Azure/gocover/pkg/gocover",
+			"github.com/Azure/gocover/pkg/gittool",
+			"github.com/Azure/gocover/pkg/dbclient",
+			"github.com/Azure/gocover/pkg/cmd",
+			"github.com/Azure/gocover/pkg/annotation",
+			"github.com/Azure/gocover",
+		} {
+			if _, ok := parser.packagesCache[pkg]; !ok {
+				t.Errorf("package %s is not in packagesCache", pkg)
+			}
+			if _, ok := parser.packages[pkg]; !ok {
+				t.Errorf("package %s is not in packages", pkg)
+			}
+		}
+	})
+}
+
 func TestSetStatementsState(t *testing.T) {
 	t.Run("change is nil", func(t *testing.T) {
 		parser := &Parser{}

pkg/parser/testdata/README.md

@@ -0,0 +1,8 @@
+## How to prepare test data
+
+In the root folder of the project, run the following command:
+
+```bash
+$ go test ./... -coverprofile cover.out -coverpkg=./... cover.out
+$ mv cover.out pkg/parser/testdata/
+```