Move splitFileExt to the android package.

Both Rust and cc use this function, so move it over to android
package's util.go and export it.

Bug: 140734195
Test: m -j

Change-Id: Ibe8b7a94592e402468a027ad6027b187f29c8e07
diff --git a/Android.bp b/Android.bp
index 537b58b..25038c6 100644
--- a/Android.bp
+++ b/Android.bp
@@ -208,7 +208,6 @@
         "cc/prebuilt_test.go",
         "cc/proto_test.go",
         "cc/test_data_test.go",
-        "cc/util_test.go",
     ],
     pluginFor: ["soong_build"],
 }
diff --git a/android/util.go b/android/util.go
index e02cca1..0102442 100644
--- a/android/util.go
+++ b/android/util.go
@@ -16,6 +16,7 @@
 
 import (
 	"fmt"
+	"path/filepath"
 	"reflect"
 	"regexp"
 	"runtime"
@@ -292,3 +293,29 @@
 	}
 	return strings.HasPrefix(str, pat[:i]) && strings.HasSuffix(str, pat[i+1:])
 }
+
+var shlibVersionPattern = regexp.MustCompile("(?:\\.\\d+(?:svn)?)+")
+
+// splitFileExt splits a file name into root, suffix and ext. root stands for the file name without
+// the file extension and the version number (e.g. "libexample"). suffix stands for the
+// concatenation of the file extension and the version number (e.g. ".so.1.0"). ext stands for the
+// file extension after the version numbers are trimmed (e.g. ".so").
+func SplitFileExt(name string) (string, string, string) {
+	// Extract and trim the shared lib version number if the file name ends with dot digits.
+	suffix := ""
+	matches := shlibVersionPattern.FindAllStringIndex(name, -1)
+	if len(matches) > 0 {
+		lastMatch := matches[len(matches)-1]
+		if lastMatch[1] == len(name) {
+			suffix = name[lastMatch[0]:lastMatch[1]]
+			name = name[0:lastMatch[0]]
+		}
+	}
+
+	// Extract the file name root and the file extension.
+	ext := filepath.Ext(name)
+	root := strings.TrimSuffix(name, ext)
+	suffix = ext + suffix
+
+	return root, suffix, ext
+}
diff --git a/android/util_test.go b/android/util_test.go
index 2e5eb07..1df1c5a 100644
--- a/android/util_test.go
+++ b/android/util_test.go
@@ -404,3 +404,68 @@
 	// b = ["foo" "bar"]
 	// c = ["foo" "baz"]
 }
+
+func TestSplitFileExt(t *testing.T) {
+	t.Run("soname with version", func(t *testing.T) {
+		root, suffix, ext := SplitFileExt("libtest.so.1.0.30")
+		expected := "libtest"
+		if root != expected {
+			t.Errorf("root should be %q but got %q", expected, root)
+		}
+		expected = ".so.1.0.30"
+		if suffix != expected {
+			t.Errorf("suffix should be %q but got %q", expected, suffix)
+		}
+		expected = ".so"
+		if ext != expected {
+			t.Errorf("ext should be %q but got %q", expected, ext)
+		}
+	})
+
+	t.Run("soname with svn version", func(t *testing.T) {
+		root, suffix, ext := SplitFileExt("libtest.so.1svn")
+		expected := "libtest"
+		if root != expected {
+			t.Errorf("root should be %q but got %q", expected, root)
+		}
+		expected = ".so.1svn"
+		if suffix != expected {
+			t.Errorf("suffix should be %q but got %q", expected, suffix)
+		}
+		expected = ".so"
+		if ext != expected {
+			t.Errorf("ext should be %q but got %q", expected, ext)
+		}
+	})
+
+	t.Run("version numbers in the middle should be ignored", func(t *testing.T) {
+		root, suffix, ext := SplitFileExt("libtest.1.0.30.so")
+		expected := "libtest.1.0.30"
+		if root != expected {
+			t.Errorf("root should be %q but got %q", expected, root)
+		}
+		expected = ".so"
+		if suffix != expected {
+			t.Errorf("suffix should be %q but got %q", expected, suffix)
+		}
+		expected = ".so"
+		if ext != expected {
+			t.Errorf("ext should be %q but got %q", expected, ext)
+		}
+	})
+
+	t.Run("no known file extension", func(t *testing.T) {
+		root, suffix, ext := SplitFileExt("test.exe")
+		expected := "test"
+		if root != expected {
+			t.Errorf("root should be %q but got %q", expected, root)
+		}
+		expected = ".exe"
+		if suffix != expected {
+			t.Errorf("suffix should be %q but got %q", expected, suffix)
+		}
+		if ext != expected {
+			t.Errorf("ext should be %q but got %q", expected, ext)
+		}
+	})
+}
diff --git a/cc/androidmk.go b/cc/androidmk.go
index 4b0cb31..66dd838 100644
--- a/cc/androidmk.go
+++ b/cc/androidmk.go
@@ -207,7 +207,7 @@
 		library.androidMkWriteExportedFlags(w)
 		library.androidMkWriteAdditionalDependenciesForSourceAbiDiff(w)
 
-		_, _, ext := splitFileExt(outputFile.Base())
+		_, _, ext := android.SplitFileExt(outputFile.Base())
 
 		fmt.Fprintln(w, "LOCAL_BUILT_MODULE_STEM := $(LOCAL_MODULE)"+ext)
 
@@ -319,7 +319,7 @@
 func (library *toolchainLibraryDecorator) AndroidMk(ctx AndroidMkContext, ret *android.AndroidMkData) {
 	ret.Class = "STATIC_LIBRARIES"
 	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
-		_, suffix, _ := splitFileExt(outputFile.Base())
+		_, suffix, _ := android.SplitFileExt(outputFile.Base())
 		fmt.Fprintln(w, "LOCAL_MODULE_SUFFIX := "+suffix)
 	})
 }
@@ -334,7 +334,7 @@
 	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
 		path := installer.path.RelPathString()
 		dir, file := filepath.Split(path)
-		stem, suffix, _ := splitFileExt(file)
+		stem, suffix, _ := android.SplitFileExt(file)
 		fmt.Fprintln(w, "LOCAL_MODULE_SUFFIX := "+suffix)
 		fmt.Fprintln(w, "LOCAL_MODULE_PATH := $(OUT_DIR)/"+filepath.Clean(dir))
 		fmt.Fprintln(w, "LOCAL_MODULE_STEM := "+stem)
@@ -347,7 +347,7 @@
 
 	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
 		path, file := filepath.Split(c.installPath.String())
-		stem, suffix, _ := splitFileExt(file)
+		stem, suffix, _ := android.SplitFileExt(file)
 		fmt.Fprintln(w, "LOCAL_MODULE_SUFFIX := "+suffix)
 		fmt.Fprintln(w, "LOCAL_MODULE_PATH := "+path)
 		fmt.Fprintln(w, "LOCAL_MODULE_STEM := "+stem)
@@ -361,7 +361,7 @@
 
 	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
 		c.libraryDecorator.androidMkWriteExportedFlags(w)
-		_, _, ext := splitFileExt(outputFile.Base())
+		_, _, ext := android.SplitFileExt(outputFile.Base())
 
 		fmt.Fprintln(w, "LOCAL_BUILT_MODULE_STEM := $(LOCAL_MODULE)"+ext)
 		fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE := true")
@@ -380,7 +380,7 @@
 
 		path := c.path.RelPathString()
 		dir, file := filepath.Split(path)
-		stem, suffix, ext := splitFileExt(file)
+		stem, suffix, ext := android.SplitFileExt(file)
 		fmt.Fprintln(w, "LOCAL_BUILT_MODULE_STEM := $(LOCAL_MODULE)"+ext)
 		fmt.Fprintln(w, "LOCAL_MODULE_SUFFIX := "+suffix)
 		fmt.Fprintln(w, "LOCAL_MODULE_PATH := $(OUT_DIR)/"+filepath.Clean(dir))
@@ -398,7 +398,7 @@
 
 	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
 		c.libraryDecorator.androidMkWriteExportedFlags(w)
-		_, _, ext := splitFileExt(outputFile.Base())
+		_, _, ext := android.SplitFileExt(outputFile.Base())
 
 		fmt.Fprintln(w, "LOCAL_BUILT_MODULE_STEM := $(LOCAL_MODULE)"+ext)
 		fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE := true")
diff --git a/cc/util.go b/cc/util.go
index 7b8ad18..2f7bec2 100644
--- a/cc/util.go
+++ b/cc/util.go
@@ -104,32 +104,6 @@
 	return list
 }
 
-var shlibVersionPattern = regexp.MustCompile("(?:\\.\\d+(?:svn)?)+")
-
-// splitFileExt splits a file name into root, suffix and ext. root stands for the file name without
-// the file extension and the version number (e.g. "libexample"). suffix stands for the
-// concatenation of the file extension and the version number (e.g. ".so.1.0"). ext stands for the
-// file extension after the version numbers are trimmed (e.g. ".so").
-func splitFileExt(name string) (string, string, string) {
-	// Extract and trim the shared lib version number if the file name ends with dot digits.
-	suffix := ""
-	matches := shlibVersionPattern.FindAllStringIndex(name, -1)
-	if len(matches) > 0 {
-		lastMatch := matches[len(matches)-1]
-		if lastMatch[1] == len(name) {
-			suffix = name[lastMatch[0]:lastMatch[1]]
-			name = name[0:lastMatch[0]]
-		}
-	}
-
-	// Extract the file name root and the file extension.
-	ext := filepath.Ext(name)
-	root := strings.TrimSuffix(name, ext)
-	suffix = ext + suffix
-
-	return root, suffix, ext
-}
-
 // linkDirOnDevice/linkName -> target
 func makeSymlinkCmd(linkDirOnDevice string, linkName string, target string) string {
 	dir := filepath.Join("$(PRODUCT_OUT)", linkDirOnDevice)
diff --git a/cc/util_test.go b/cc/util_test.go
deleted file mode 100644
index 7c718ea..0000000
--- a/cc/util_test.go
+++ /dev/null
@@ -1,84 +0,0 @@
-// Copyright 2018 Google Inc. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package cc
-
-import (
-	"testing"
-)
-
-func TestSplitFileExt(t *testing.T) {
-	t.Run("soname with version", func(t *testing.T) {
-		root, suffix, ext := splitFileExt("libtest.so.1.0.30")
-		expected := "libtest"
-		if root != expected {
-			t.Errorf("root should be %q but got %q", expected, root)
-		}
-		expected = ".so.1.0.30"
-		if suffix != expected {
-			t.Errorf("suffix should be %q but got %q", expected, suffix)
-		}
-		expected = ".so"
-		if ext != expected {
-			t.Errorf("ext should be %q but got %q", expected, ext)
-		}
-	})
-
-	t.Run("soname with svn version", func(t *testing.T) {
-		root, suffix, ext := splitFileExt("libtest.so.1svn")
-		expected := "libtest"
-		if root != expected {
-			t.Errorf("root should be %q but got %q", expected, root)
-		}
-		expected = ".so.1svn"
-		if suffix != expected {
-			t.Errorf("suffix should be %q but got %q", expected, suffix)
-		}
-		expected = ".so"
-		if ext != expected {
-			t.Errorf("ext should be %q but got %q", expected, ext)
-		}
-	})
-
-	t.Run("version numbers in the middle should be ignored", func(t *testing.T) {
-		root, suffix, ext := splitFileExt("libtest.1.0.30.so")
-		expected := "libtest.1.0.30"
-		if root != expected {
-			t.Errorf("root should be %q but got %q", expected, root)
-		}
-		expected = ".so"
-		if suffix != expected {
-			t.Errorf("suffix should be %q but got %q", expected, suffix)
-		}
-		expected = ".so"
-		if ext != expected {
-			t.Errorf("ext should be %q but got %q", expected, ext)
-		}
-	})
-
-	t.Run("no known file extension", func(t *testing.T) {
-		root, suffix, ext := splitFileExt("test.exe")
-		expected := "test"
-		if root != expected {
-			t.Errorf("root should be %q but got %q", expected, root)
-		}
-		expected = ".exe"
-		if suffix != expected {
-			t.Errorf("suffix should be %q but got %q", expected, suffix)
-		}
-		if ext != expected {
-			t.Errorf("ext should be %q but got %q", expected, ext)
-		}
-	})
-}
diff --git a/rust/androidmk.go b/rust/androidmk.go
index c9056e1..107959f 100644
--- a/rust/androidmk.go
+++ b/rust/androidmk.go
@@ -18,7 +18,6 @@
 	"fmt"
 	"io"
 	"path/filepath"
-	"regexp"
 	"strings"
 
 	"android/soong/android"
@@ -119,37 +118,9 @@
 	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
 		path := compiler.path.RelPathString()
 		dir, file := filepath.Split(path)
-		stem, suffix, _ := splitFileExt(file)
+		stem, suffix, _ := android.SplitFileExt(file)
 		fmt.Fprintln(w, "LOCAL_MODULE_SUFFIX := "+suffix)
 		fmt.Fprintln(w, "LOCAL_MODULE_PATH := $(OUT_DIR)/"+filepath.Clean(dir))
 		fmt.Fprintln(w, "LOCAL_MODULE_STEM := "+stem)
 	})
 }
-
-//TODO: splitFileExt copied from cc/util.go; move this to android/util.go and refactor usages.
-
-// splitFileExt splits a file name into root, suffix and ext. root stands for the file name without
-// the file extension and the version number (e.g. "libexample"). suffix stands for the
-// concatenation of the file extension and the version number (e.g. ".so.1.0"). ext stands for the
-// file extension after the version numbers are trimmed (e.g. ".so").
-var shlibVersionPattern = regexp.MustCompile("(?:\\.\\d+(?:svn)?)+")
-
-func splitFileExt(name string) (string, string, string) {
-	// Extract and trim the shared lib version number if the file name ends with dot digits.
-	suffix := ""
-	matches := shlibVersionPattern.FindAllStringIndex(name, -1)
-	if len(matches) > 0 {
-		lastMatch := matches[len(matches)-1]
-		if lastMatch[1] == len(name) {
-			suffix = name[lastMatch[0]:lastMatch[1]]
-			name = name[0:lastMatch[0]]
-		}
-	}
-
-	// Extract the file name root and the file extension.
-	ext := filepath.Ext(name)
-	root := strings.TrimSuffix(name, ext)
-	suffix = ext + suffix
-
-	return root, suffix, ext
-}