Check committed file sizes

internal/validation/file_size.go

@@ -0,0 +1,52 @@
+package validation
+
+import (
+	"path"
+	"strings"
+)
+
+const defaultFileSizeLimit int64 = 1_000_000
+
+func checkFileSize(tree *CandidateTree, settings *FileSizeSettings) error {
+	limit := defaultFileSizeLimit
+	if settings.LimitBytes != nil {
+		limit = *settings.LimitBytes
+	}
+	exclusions := normalizedExclusions(settings.Exclusions)
+	for _, entry := range tree.Entries() {
+		if entry.Type != "blob" || !entry.HasSize || excludedByPath(entry.Path, exclusions) {
+			continue
+		}
+		if entry.Size > limit {
+			return &Failure{
+				Check: FileSize,
+				Findings: []Finding{{
+					Path:    entry.Path,
+					Message: "committed file exceeds the selected size limit",
+				}},
+				Measurement: &FileSizeMeasurement{Bytes: entry.Size, LimitBytes: limit},
+			}
+		}
+	}
+	return nil
+}
+
+func normalizedExclusions(exclusions []string) []string {
+	result := make([]string, 0, len(exclusions))
+	for _, exclusion := range exclusions {
+		if exclusion == "" {
+			continue
+		}
+		result = append(result, path.Clean(exclusion))
+	}
+	return result
+}
+
+func excludedByPath(filePath string, exclusions []string) bool {
+	for _, exclusion := range exclusions {
+		if exclusion == "." || filePath == exclusion || strings.HasPrefix(filePath, exclusion+"/") {
+			return true
+		}
+	}
+	return false
+}