Adds UserCacheHome. (#2)

Author: coollog

skaffold-plugins-core/src/main/java/com/google/cloud/tools/skaffold/filesystem/UserCacheHome.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2018 Google LLC. 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 com.google.cloud.tools.skaffold.filesystem;
+
+import com.google.common.annotations.VisibleForTesting;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Properties;
+import java.util.logging.Logger;
+
+/**
+ * Obtains an OS-specific user cache directory based on the XDG Base Directory Specification.
+ *
+ * <p>Specifically, from the specification:
+ *
+ * <ul>
+ *   <li>This directory is defined by the environment variable {@code $XDG_CACHE_HOME}.
+ *   <li>If {@code $XDG_CACHE_HOME} is either not set or empty, a default equal to {@code
+ *       $HOME/.cache} should be used.
+ * </ul>
+ *
+ * @see <a
+ *     href="https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html">https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html</a>
+ */
+public class UserCacheHome {
+
+  private static final Logger logger = Logger.getLogger(UserCacheHome.class.getName());
+
+  public static Path getCacheHome() {
+    return getCacheHome(System.getProperties(), System.getenv());
+  }
+
+  /**
+   * Returns {@code $XDG_CACHE_HOME}, if available, or resolves the OS-specific user cache home
+   * based.
+   *
+   * <p>For Linus, this is {@code $HOME/.cache/}.
+   *
+   * <p>For Windows, this is {@code %LOCALAPPDATA%}.
+   *
+   * <p>For macOS, this is {@code $HOME/Library/Application Support/}.
+   */
+  @VisibleForTesting
+  static Path getCacheHome(Properties properties, Map<String, String> environment) {
+    // Use environment variable $XDG_CACHE_HOME if set and not empty.
+    String xdgCacheHome = environment.get("XDG_CACHE_HOME");
+    if (xdgCacheHome != null && !xdgCacheHome.trim().isEmpty()) {
+      return Paths.get(xdgCacheHome);
+    }
+
+    String userHome = properties.getProperty("user.home");
+
+    Path userHomeDirectory = Paths.get(userHome);
+    Path xdgPath = userHomeDirectory.resolve(".cache");
+
+    String rawOsName = properties.getProperty("os.name");
+    String osName = rawOsName.toLowerCase(Locale.ENGLISH);
+
+    if (osName.contains("linux")) {
+      return xdgPath;
+
+    } else if (osName.contains("windows")) {
+      // Use %LOCALAPPDATA% for Windows.
+      String localAppDataEnv = environment.get("LOCALAPPDATA");
+      if (localAppDataEnv == null || localAppDataEnv.trim().isEmpty()) {
+        logger.warning("LOCALAPPDATA environment is invalid or missing");
+        return xdgPath;
+      }
+      Path localAppData = Paths.get(localAppDataEnv);
+      if (!Files.exists(localAppData)) {
+        logger.warning(localAppData + " does not exist");
+        return xdgPath;
+      }
+      return localAppData;
+
+    } else if (osName.contains("mac") || osName.contains("darwin")) {
+      // Use '~/Library/Application Support/' for macOS.
+      Path applicationSupport = userHomeDirectory.resolve("Library").resolve("Application Support");
+      if (!Files.exists(applicationSupport)) {
+        logger.warning(applicationSupport + " does not exist");
+        return xdgPath;
+      }
+      return applicationSupport;
+    }
+
+    throw new IllegalStateException("Unknown OS: " + rawOsName);
+  }
+
+  private UserCacheHome() {}
+}

skaffold-plugins-core/src/test/java/com/google/cloud/tools/skaffold/filesystem/UserCacheHomeTest.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2018 Google LLC. 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 com.google.cloud.tools.skaffold.filesystem;
+
+import com.google.common.collect.ImmutableMap;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Properties;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.mockito.Mockito;
+
+/** Tests for {@link UserCacheHome}. */
+public class UserCacheHomeTest {
+
+  @Rule public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+  private String fakeCacheHome;
+
+  @Before
+  public void setUp() throws IOException {
+    fakeCacheHome = temporaryFolder.newFolder().getPath();
+  }
+
+  @Test
+  public void testGetCacheHome_hasXdgCacheHome() {
+    Map<String, String> fakeEnvironment = ImmutableMap.of("XDG_CACHE_HOME", fakeCacheHome);
+
+    Assert.assertEquals(
+        Paths.get(fakeCacheHome),
+        UserCacheHome.getCacheHome(Mockito.mock(Properties.class), fakeEnvironment));
+  }
+
+  @Test
+  public void testGetCacheHome_linux() {
+    Properties fakeProperties = new Properties();
+    fakeProperties.setProperty("user.home", fakeCacheHome);
+    fakeProperties.setProperty("os.name", "os is LiNuX");
+
+    Assert.assertEquals(
+        Paths.get(fakeCacheHome).resolve(".cache"),
+        UserCacheHome.getCacheHome(fakeProperties, Collections.emptyMap()));
+  }
+
+  @Test
+  public void testGetCacheHome_windows() {
+    Properties fakeProperties = new Properties();
+    fakeProperties.setProperty("user.home", "nonexistent");
+    fakeProperties.setProperty("os.name", "os is WiNdOwS");
+
+    Map<String, String> fakeEnvironment = ImmutableMap.of("LOCALAPPDATA", fakeCacheHome);
+
+    Assert.assertEquals(
+        Paths.get(fakeCacheHome), UserCacheHome.getCacheHome(fakeProperties, fakeEnvironment));
+  }
+
+  @Test
+  public void testGetCacheHome_mac() throws IOException {
+    Path libraryApplicationSupport =
+        Paths.get(fakeCacheHome).resolve("Library").resolve("Application Support");
+    Files.createDirectories(libraryApplicationSupport);
+
+    Properties fakeProperties = new Properties();
+    fakeProperties.setProperty("user.home", fakeCacheHome);
+    fakeProperties.setProperty("os.name", "os is mAc or DaRwIn");
+
+    Assert.assertEquals(
+        libraryApplicationSupport,
+        UserCacheHome.getCacheHome(fakeProperties, Collections.emptyMap()));
+  }
+}