Merge "Speed up vendor snapshot header globs" am: ab15f9644b

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/1554550

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I28e83f1869b7f3af37b15046bb783659ad5ec1d2

cc/library.go

@@ -449,24 +449,38 @@ func (l *libraryDecorator) collectHeadersForSnapshot(ctx android.ModuleContext)
 			}
 			continue
 		}
-		exts := headerExts
-		// Glob all files under this special directory, because of C++ headers.
-		if strings.HasPrefix(dir, "external/libcxx/include") {
-			exts = []string{""}
-		}
-		for _, ext := range exts {
-			glob, err := ctx.GlobWithDeps(dir+"/**/*"+ext, nil)
+		glob, err := ctx.GlobWithDeps(dir+"/**/*", nil)
 		if err != nil {
 			ctx.ModuleErrorf("glob failed: %#v", err)
 			return
 		}
-			for _, header := range glob {
-				if strings.HasSuffix(header, "/") {
+		isLibcxx := strings.HasPrefix(dir, "external/libcxx/include")
+		j := 0
+		for i, header := range glob {
+			if isLibcxx {
+				// Glob all files under this special directory, because of C++ headers with no
+				// extension.
+				if !strings.HasSuffix(header, "/") {
 					continue
 				}
-				ret = append(ret, android.PathForSource(ctx, header))
+			} else {
+				// Filter out only the files with extensions that are headers.
+				found := false
+				for _, ext := range headerExts {
+					if strings.HasSuffix(header, ext) {
+						found = true
+						break
 					}
 				}
+				if !found {
+					continue
+				}
+			}
+			if i != j {
+				glob[j] = glob[i]
+			}
+			j++
+		}
 	}
 
 	// Collect generated headers