2 files changed, 142 insertions, 0 deletions
diff --git a/luni/src/main/java/libcore/net/http/ResponseUtils.java b/luni/src/main/java/libcore/net/http/ResponseUtils.java
new file mode 100644
index 0000000..c892b53
--- /dev/null
+++ b/luni/src/main/java/libcore/net/http/ResponseUtils.java
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * 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 libcore.net.http;
+
+import java.nio.charset.Charset;
+import java.nio.charset.IllegalCharsetNameException;
+import java.nio.charset.StandardCharsets;
+import java.nio.charset.UnsupportedCharsetException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @hide
+ */
+public class ResponseUtils {
+  /**
+   * Returns the response charset of a HTTP response based on the {@code Content-Type} of
+   * the response (see RFC 7230). If the {@code Content-Type} header is missing or invalid,
+   * the response is assumed to be encoded as {@code UTF-8}. Note that a charset usually
+   * makes sense only for {@code "text/plain"} and other "text based" responses.
+   *
+   * @throws IllegalCharsetNameException if the response specified charset is illegal.
+   * @throws UnsupportedCharsetException if the response specified charset is unsupported.
+   */
+  public static Charset responseCharset(String contentTypeHeader)
+      throws IllegalCharsetNameException, UnsupportedCharsetException {
+    Charset responseCharset = StandardCharsets.UTF_8;
+    if (contentTypeHeader != null) {
+      Map<String, String> contentTypeParams = parseContentTypeParameters(contentTypeHeader);
+      String charsetParameter = contentTypeParams.get("charset");
+      if (charsetParameter != null) {
+        responseCharset = Charset.forName(charsetParameter);
+      }
+    }
+
+    return responseCharset;
+  }
+
+  /**
+   * Parse content-type parameters. The format of this header is roughly :
+   * {@code type/subtype; param1=value1; param2=value2 ...} where each of the
+   * parameters are optional. Parsing is lenient, malformed parameters are ignored.
+   *
+   * Parameter keys & values are trimmed of whitespace and keys are converted to
+   * lower case.
+   */
+  private static Map<String, String> parseContentTypeParameters(String contentTypeHeader) {
+    Map<String, String> parameters = Collections.EMPTY_MAP;
+
+    String[] fields = contentTypeHeader.split(";");
+    if (fields.length > 1) {
+      parameters = new HashMap<>();
+      // Ignore the first element in the array (the type/subtype).
+      for (int i = 1; i < fields.length; ++i) {
+        final String parameter = fields[i];
+        if (!parameter.isEmpty()) {
+          final String[] components = parameter.split("=");
+          if (components.length != 2) {
+            continue;
+          }
+
+          final String key = components[0].trim().toLowerCase();
+          final String value = components[1].trim();
+          if (key.isEmpty() || value.isEmpty()) {
+            continue;
+          }
+
+          parameters.put(key, value);
+        }
+      }
+    }
+
+    return parameters;
+  }
+}
diff --git a/luni/src/test/java/libcore/net/http/ResponseUtilsTest.java b/luni/src/test/java/libcore/net/http/ResponseUtilsTest.java
new file mode 100644
index 0000000..16745ee
--- /dev/null
+++ b/luni/src/test/java/libcore/net/http/ResponseUtilsTest.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * 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 libcore.net.http;
+
+import java.nio.charset.StandardCharsets;
+import java.nio.charset.UnsupportedCharsetException;
+import junit.framework.TestCase;
+import static libcore.net.http.ResponseUtils.responseCharset;
+
+public class ResponseUtilsTest extends TestCase {
+  public void test_responseCharset_missing() {
+    assertEquals(StandardCharsets.UTF_8, responseCharset(null));
+    assertEquals(StandardCharsets.UTF_8, responseCharset("text/plain"));
+    assertEquals(StandardCharsets.UTF_8, responseCharset("text/plain;foo=bar;baz=bal"));
+    assertEquals(StandardCharsets.UTF_8, responseCharset("text/plain;charset="));
+  }
+
+  public void test_responseCharset_valid() {
+    assertEquals(StandardCharsets.ISO_8859_1,
+            responseCharset("text/plain;charset=ISO-8859-1"));
+    assertEquals(StandardCharsets.ISO_8859_1,
+            responseCharset("text/plain;CHARSET=ISO-8859-1"));
+    assertEquals(StandardCharsets.ISO_8859_1,
+            responseCharset("text/plain;   charset  =   ISO-8859-1"));
+    assertEquals(StandardCharsets.ISO_8859_1,
+            responseCharset("text/plain; foo=bar;baz=bag;charset=ISO-8859-1"));
+    assertEquals(StandardCharsets.ISO_8859_1,
+            responseCharset("text/plain;charset=ISO-8859-1;;==,=="));
+  }
+
+  public void test_responseCharset_invalid() {
+    try {
+      responseCharset("text/plain;charset=unsupportedCharset");
+      fail();
+    } catch (UnsupportedCharsetException expected) {
+    }
+  }
+}