Android: support escapes in multiline strings definitions

This adds support for escape characters in multiline strings definitions
(where the variable name and the string literal are on different lines,
not for string literals which span multiple lines). This also simplifies
STRING_RE because it no longer needs to contain a regex for the string
literal.

This also adds tests for empty string. This hardens the regex to avoid
mistaking multiple string literals (which is often used to split a
string literal across multiple lines) with a complete string expression.

This also removes _ToUpper and _GetClassName because these are unused by
this class.

Fixed: 1129591
Test: vpython build/android/gyp/java_cpp_strings_tests.py
Change-Id: Ib4b6dcc2bbe70081ebaaa3552b4cb6d36dc0ffe9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417488Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808180}

build/android/gyp/java_cpp_strings.py

@@ -14,18 +14,6 @@ from util import build_utils
 from util import java_cpp_utils
 
 
-def _ToUpper(match):
-  return match.group(1).upper()
-
-
-def _GetClassName(source_path):
-  name = os.path.basename(os.path.abspath(source_path))
-  (name, _) = os.path.splitext(name)
-  name = re.sub(r'_([a-z])', _ToUpper, name)
-  name = re.sub(r'^(.)', _ToUpper, name)
-  return name
-
-
 class _String(object):
 
   def __init__(self, name, value, comments):
@@ -61,8 +49,8 @@ def ParseTemplateFile(lines):
 # in the file to be parsed.
 class StringFileParser(object):
   SINGLE_LINE_COMMENT_RE = re.compile(r'\s*(// [^\n]*)')
-  STRING_RE = re.compile(r'\s*const char k(.*)\[\]\s*=\s*(?:(".*"))?')
-  VALUE_RE = re.compile(r'\s*("[^"]*")')
+  STRING_RE = re.compile(r'\s*const char k(.*)\[\]\s*=')
+  VALUE_RE = re.compile(r'\s*("(?:\"|[^"])*")\s*;')
 
   def __init__(self, lines, path=''):
     self._lines = lines
@@ -75,6 +63,14 @@ class StringFileParser(object):
     self._current_value = ''
     self._strings = []
 
+  def _ExtractVariable(self, line):
+    match = StringFileParser.STRING_RE.match(line)
+    return match.group(1) if match else None
+
+  def _ExtractValue(self, line):
+    match = StringFileParser.VALUE_RE.search(line)
+    return match.group(1) if match else None
+
   def _Reset(self):
     self._current_comments = []
     self._current_name = ''
@@ -89,9 +85,9 @@ class StringFileParser(object):
     self._Reset()
 
   def _ParseValue(self, line):
-    value_line = StringFileParser.VALUE_RE.match(line)
-    if value_line:
-      self._current_value = value_line.groups()[0]
+    current_value = self._ExtractValue(line)
+    if current_value is not None:
+      self._current_value = current_value
       self._AppendString()
     else:
       self._Reset()
@@ -108,11 +104,12 @@ class StringFileParser(object):
       return False
 
   def _ParseString(self, line):
-    string_line = StringFileParser.STRING_RE.match(line)
-    if string_line:
-      self._current_name = string_line.groups()[0]
-      if string_line.groups()[1]:
-        self._current_value = string_line.groups()[1]
+    current_name = self._ExtractVariable(line)
+    if current_name is not None:
+      self._current_name = current_name
+      current_value = self._ExtractValue(line)
+      if current_value is not None:
+        self._current_value = current_value
         self._AppendString()
       else:
         self._in_string = True

build/android/gyp/java_cpp_strings_tests.py

@@ -46,7 +46,7 @@ const char kAnotherSwitch[] = "another-value";
     self.assertEqual(2, len(strings[1].comments.split('\n')))
 
   def testStringValues(self):
-    test_data = """
+    test_data = r"""
 // Single line string constants.
 const char kAString[] = "a-value";
 const char kNoComment[] = "no-comment";
@@ -67,13 +67,23 @@ const char kAStringWithAVeryLongNameThatWillHaveToWrap[] =
 const char kAStringWithAVeryLongNameThatWillHaveToWrap2[] =
     "a-string-with-a-very-long-name-that-will-have-to-wrap2";
 
-// This is erroneous and should be ignored.
+const char kStringWithEscapes[] = "tab\tquote\"newline\n";
+const char kStringWithEscapes2[] =
+    "tab\tquote\"newline\n";
+
+const char kEmptyString[] = "";
+
+// These are valid C++ but not currently supported by the script.
 const char kInvalidLineBreak[] =
 
     "invalid-line-break";
+
+const char kConcatenateMultipleStringLiterals[] =
+    "first line"
+    "second line";
 """.split('\n')
     strings = java_cpp_strings.StringFileParser(test_data).Parse()
-    self.assertEqual(6, len(strings))
+    self.assertEqual(9, len(strings))
     self.assertEqual('A_STRING', strings[0].name)
     self.assertEqual('"a-value"', strings[0].value)
     self.assertEqual('NO_COMMENT', strings[1].name)
@@ -90,6 +100,12 @@ const char kInvalidLineBreak[] =
                      strings[5].name)
     self.assertEqual('"a-string-with-a-very-long-name-that-will-have-to-wrap2"',
                      strings[5].value)
+    self.assertEqual('STRING_WITH_ESCAPES', strings[6].name)
+    self.assertEqual(r'"tab\tquote\"newline\n"', strings[6].value)
+    self.assertEqual('STRING_WITH_ESCAPES2', strings[7].name)
+    self.assertEqual(r'"tab\tquote\"newline\n"', strings[7].value)
+    self.assertEqual('EMPTY_STRING', strings[8].name)
+    self.assertEqual('""', strings[8].value)
 
   def testTreatWebViewLikeOneWord(self):
     test_data = """