Support custom logsite formatting in SimpleAndroidLoggerBackend.

RELNOTES=Support custom logsite formatting in SimpleAndroidLoggerBackend.
PiperOrigin-RevId: 565490675

api/src/main/java/com/google/common/flogger/backend/LogSiteFormatter.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2023 The Flogger Authors.
+ *
+ * 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.common.flogger.backend;
+
+import com.google.common.flogger.LogSite;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+
+/** Interface for custom LogSite formatting. */
+public interface LogSiteFormatter {
+
+  /**
+   * Appends log site information to a buffer.
+   *
+   * @param logSite the log site to be appended (ignored if {@link LogSite#INVALID}).
+   * @param out the destination buffer.
+   * @return whether the logSite was appended.
+   */
+  @CanIgnoreReturnValue
+  boolean appendLogSite(LogSite logSite, StringBuilder out);
+}

api/src/main/java/com/google/common/flogger/backend/LogSiteFormatters.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2023 The Flogger Authors.
+ *
+ * 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.common.flogger.backend;
+
+import com.google.common.flogger.LogSite;
+
+/** Sample LogSiteFormatter implementations. */
+public enum LogSiteFormatters implements LogSiteFormatter {
+  DEFAULT {
+    /** Appends logsite information in the default format, <className>.<methodName>:<lineNumber> */
+    @Override
+    public boolean appendLogSite(LogSite logSite, StringBuilder out) {
+      if (logSite == LogSite.INVALID) {
+        return false;
+      }
+      out.append(logSite.getClassName())
+          .append('.')
+          .append(logSite.getMethodName())
+          .append(':')
+          .append(logSite.getLineNumber());
+      return true;
+    }
+  },
+  NO_OP {
+    /** Does not append logsite information. */
+    @Override
+    public boolean appendLogSite(LogSite logSite, StringBuilder out) {
+      return false;
+    }
+  },
+  SIMPLE_CLASSNAME {
+    /**
+     * Appends logsite information using the unqualified class name,
+     * <simpleClassName>.<methodName>:<lineNumber>
+     *
+     * <p>The unqualified class name is all text after the last period. A class name with no
+     * separators or a trailing separator will be appended in full.
+     */
+    @Override
+    public boolean appendLogSite(LogSite logSite, StringBuilder out) {
+      if (logSite == LogSite.INVALID) {
+        return false;
+      }
+      String qualifiedClassName = logSite.getClassName();
+      int lastDotIndex = qualifiedClassName.lastIndexOf('.');
+      if (lastDotIndex == -1 || lastDotIndex + 1 >= qualifiedClassName.length()) {
+        out.append(qualifiedClassName);
+      } else {
+        out.append(qualifiedClassName, lastDotIndex + 1, qualifiedClassName.length());
+      }
+      out.append('.').append(logSite.getMethodName()).append(':').append(logSite.getLineNumber());
+      return true;
+    }
+  }
+}

api/src/main/java/com/google/common/flogger/backend/MessageUtils.java

@@ -47,23 +47,15 @@ private MessageUtils() {}
   static final Locale FORMAT_LOCALE = Locale.ROOT;
 
   /**
-   * Appends log-site information in the default format, including a trailing space.
+   * Appends log-site information in the default format.
    *
-   * @param logSite the log site to be appended (ingored if {@link LogSite#INVALID}).
+   * @param logSite the log site to be appended (ignored if {@link LogSite#INVALID}).
    * @param out the destination buffer.
    * @return whether the log-site was appended.
    */
   @CanIgnoreReturnValue
   public static boolean appendLogSite(LogSite logSite, StringBuilder out) {
-    if (logSite == LogSite.INVALID) {
-      return false;
-    }
-    out.append(logSite.getClassName())
-        .append('.')
-        .append(logSite.getMethodName())
-        .append(':')
-        .append(logSite.getLineNumber());
-    return true;
+    return LogSiteFormatters.DEFAULT.appendLogSite(logSite, out);
   }
 
   /**

api/src/test/java/com/google/common/flogger/backend/LogSiteFormattersTest.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2023 The Flogger Authors.
+ *
+ * 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.common.flogger.backend;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.flogger.LogSite;
+import com.google.common.flogger.testing.FakeLogSite;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public final class LogSiteFormattersTest {
+
+  @Test
+  public void testInvalidLogSite() {
+    for (LogSiteFormatter formatter : LogSiteFormatters.values()) {
+      StringBuilder out = new StringBuilder();
+      assertThat(formatter.appendLogSite(LogSite.INVALID, out)).isFalse();
+      assertThat(out.toString()).isEmpty();
+    }
+  }
+
+  @Test
+  public void testAppendLogSite_default() {
+    StringBuilder out = new StringBuilder();
+    LogSite logSite = FakeLogSite.create("<class>", "<method>", 32, "Ignored.java");
+    assertThat(LogSiteFormatters.DEFAULT.appendLogSite(logSite, out)).isTrue();
+    assertThat(out.toString()).isEqualTo("<class>.<method>:32");
+  }
+
+  @Test
+  public void testAppendLogSite_noOp() {
+    StringBuilder out = new StringBuilder();
+    LogSite logSite = FakeLogSite.create("<class>", "<method>", 32, "Ignored.java");
+    assertThat(LogSiteFormatters.NO_OP.appendLogSite(logSite, out)).isFalse();
+    assertThat(out.toString()).isEmpty();
+  }
+
+  @Test
+  public void testAppendLogSite_simpleClassname_qualifiedName_unqualified() {
+    StringBuilder out = new StringBuilder();
+    LogSite logSite =
+        FakeLogSite.create(
+            "com.google.common.flogger.backend.LogSiteFormattersTest",
+            "testMethod",
+            42,
+            "Ignored.java");
+    assertThat(LogSiteFormatters.SIMPLE_CLASSNAME.appendLogSite(logSite, out)).isTrue();
+    assertThat(out.toString()).isEqualTo("LogSiteFormattersTest.testMethod:42");
+  }
+
+  @Test
+  public void testAppendLogSite_simpleClassname_unqualifiedName_all() {
+    StringBuilder out = new StringBuilder();
+    LogSite logSite = FakeLogSite.create("LogSiteFormattersTest", "testMethod", 55, "Ignored.java");
+    assertThat(LogSiteFormatters.SIMPLE_CLASSNAME.appendLogSite(logSite, out)).isTrue();
+    assertThat(out.toString()).isEqualTo("LogSiteFormattersTest.testMethod:55");
+  }
+
+  @Test
+  public void testAppendLogSite_simpleClassname_trailingDot_all() {
+    StringBuilder out = new StringBuilder();
+    LogSite logSite =
+        FakeLogSite.create("LogSiteFormattersTest.", "testMethod", 63, "Ignored.java");
+    assertThat(LogSiteFormatters.SIMPLE_CLASSNAME.appendLogSite(logSite, out)).isTrue();
+    assertThat(out.toString()).isEqualTo("LogSiteFormattersTest..testMethod:63");
+  }
+
+  @Test
+  public void testAppendLogSite_simpleClassname_fakeClassName() {
+    StringBuilder out = new StringBuilder();
+    LogSite logSite = FakeLogSite.create("<class>", "<method>", 32, "Ignored.java");
+    assertThat(LogSiteFormatters.SIMPLE_CLASSNAME.appendLogSite(logSite, out)).isTrue();
+    assertThat(out.toString()).isEqualTo("<class>.<method>:32");
+  }
+}