Add path utils, plus a test for it.

tests/OSPathUtilsTest.cpp

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkString.h"
+#include "SkOSFile.h"
+#include "Test.h"
+
+/**
+ *  Test SkPathJoin and SkBasename.
+ *  Will use SkPathJoin to append filename to dir, test that it works correctly,
+ *  and tests using SkBasename on the result.
+ *  @param reporter Reporter for test conditions.
+ *  @param dir String representing the path to a folder. May or may not
+ *      end with SkPATH_SEPARATOR.
+ *  @param filename String representing the basename of a file. Must NOT
+ *      contain SkPATH_SEPARATOR.
+ */
+static void test_dir_with_file(skiatest::Reporter* reporter, SkString dir,
+                               SkString filename) {
+    // If filename contains SkPATH_SEPARATOR, the tests will fail.
+    SkASSERT(!filename.contains(SkPATH_SEPARATOR));
+
+    // Tests for SkOSPathUtils::SkPathJoin and SkOSPathUtils::SkBasename
+
+    // fullName should be "dir<SkPATH_SEPARATOR>file"
+    SkString fullName = SkOSPathUtils::SkPathJoin(dir.c_str(), filename.c_str());
+
+    // fullName should be the combined size of dir and file, plus one if
+    // dir did not include the final path separator.
+    size_t expectedSize = dir.size() + filename.size();
+    if (!dir.endsWith(SkPATH_SEPARATOR)) {
+        expectedSize++;
+    }
+    REPORTER_ASSERT(reporter, fullName.size() == expectedSize);
+
+    SkString basename = SkOSPathUtils::SkBasename(fullName.c_str());
+
+    // basename should be the same as filename
+    REPORTER_ASSERT(reporter, basename.equals(filename));
+
+    // basename will not contain a path separator
+    REPORTER_ASSERT(reporter, !basename.contains(SkPATH_SEPARATOR));
+
+    // Now take the basename of filename, which should be the same as filename.
+    basename = SkOSPathUtils::SkBasename(filename.c_str());
+    REPORTER_ASSERT(reporter, basename.equals(filename));
+}
+
+static void test_os_path_utils_tests(skiatest::Reporter* reporter) {
+    SkString dir("dir");
+    SkString filename("file");
+    test_dir_with_file(reporter, dir, filename);
+
+    // Now make sure this works with a path separator at the end of dir.
+    dir.appendUnichar(SkPATH_SEPARATOR);
+    test_dir_with_file(reporter, dir, filename);
+
+    // Test with a sub directory.
+    dir.append("subDir");
+    test_dir_with_file(reporter, dir, filename);
+
+    // Basename of a directory with a path separator at the end is empty.
+    dir.appendUnichar(SkPATH_SEPARATOR);
+    SkString baseOfDir = SkOSPathUtils::SkBasename(dir.c_str());
+    REPORTER_ASSERT(reporter, baseOfDir.size() == 0);
+
+    // Basename of NULL is an empty string.
+    SkString empty = SkOSPathUtils::SkBasename(NULL);
+    REPORTER_ASSERT(reporter, empty.size() == 0);
+}
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("OSPathUtils", OSPathUtilsTestClass, test_os_path_utils_tests)