pkg/cover: allow paths to be excluded from stats

Some sub paths may not be covered due to hardware configuration, or lack
of interest. This patch allows them to be excluded from the stats. This
can be convenient if the excluded paths are deep in the hierarchy:

{
    "name": "sound",
    "path": [
	"techpack/audio",
	"-techpack/audio/asoc/aaa/bbb"
	"-techpack/audio/asoc/aaa/ccc"
    ]
}

1 files changed, 24 insertions, 1 deletions

diff --git a/pkg/cover/html.go b/pkg/cover/html.go
index ae4aa6c4b..042d28b40 100644
--- a/pkg/cover/html.go
+++ b/pkg/cover/html.go
@@ -537,8 +537,12 @@ func groupCoverByFilePrefixes(datas []fileStats, subsystems []mgrconfig.Subsyste
 		var percentCoveredFunc float64
 
 		for _, path := range subsystem.Paths {
+			if strings.HasPrefix(path, "-") {
+				continue
+			}
+			excludes := buildExcludePaths(path, subsystem.Paths)
 			for _, data := range datas {
-				if !strings.HasPrefix(data.Name, path) {
+				if !strings.HasPrefix(data.Name, path) || isExcluded(data.Name, excludes) {
 					continue
 				}
 				coveredLines += data.CoveredLines
@@ -582,6 +586,25 @@ func groupCoverByFilePrefixes(datas []fileStats, subsystems []mgrconfig.Subsyste
 	return d
 }
 
+func buildExcludePaths(prefix string, paths []string) []string {
+	var excludes []string
+	for _, path := range paths {
+		if strings.HasPrefix(path, "-") && strings.HasPrefix(path[1:], prefix) {
+			excludes = append(excludes, path[1:])
+		}
+	}
+	return excludes
+}
+
+func isExcluded(path string, excludes []string) bool {
+	for _, exclude := range excludes {
+		if strings.HasPrefix(path, exclude) {
+			return true
+		}
+	}
+	return false
+}
+
 func (rg *ReportGenerator) DoSubsystemCover(w io.Writer, params HandlerParams) error {
 	var progs = fixUpPCs(params.Progs, params.Filter)
 	data, err := rg.convertToStats(progs)