Remove Map of headers

lib/android_build/app/src/test/java/com/microsoft/applications/events/maesdktest/HttpClientRequestTest.java

@@ -0,0 +1,40 @@
+//
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+package com.microsoft.applications.events.maesdktest;
+
+import com.microsoft.applications.events.HttpClientRequest;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.junit.Assert.*;
+
+public class HttpClientRequestTest {
+    @Test
+    public void testHeaders() {
+        byte[] bytes = "key1value1key2value2".getBytes(UTF_8);
+        int[] header_lengths = new int[] { 4, 6, 4, 6 };
+
+        HttpClientRequest.Headers headers = new HttpClientRequest.Headers(header_lengths, bytes);
+        ArrayList<String> actual = new ArrayList<>();
+        while (headers.hasNext()) {
+            HttpClientRequest.HeaderEntry entry = headers.next();
+            actual.add(entry.key);
+            actual.add(entry.value);
+        }
+
+        Assert.assertEquals(4, headers.length);
+        Assert.assertArrayEquals(
+                new String[] {"key1", "value1", "key2", "value2"},
+                actual.toArray()
+        );
+    }
+}

lib/android_build/maesdk/src/main/java/com/microsoft/applications/events/HttpClient.java

@@ -36,7 +36,7 @@
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
-import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -97,7 +97,7 @@ class Request implements HttpClientRequest {
           String method,
           byte[] body,
           String request_id,
-          @NonNull Map<String, String> headers)
+          @NonNull Headers headers)
       throws java.io.IOException {
     m_parent = parent;
     m_connection = (HttpURLConnection) parent.newUrl(url).openConnection();
@@ -108,8 +108,9 @@ class Request implements HttpClientRequest {
       m_connection.setDoOutput(true);
     }
     m_request_id = request_id;
-    for (Map.Entry<String, String> header : headers.entrySet()) {
-      m_connection.setRequestProperty(header.getKey(), header.getValue());
+    while (headers.hasNext()) {
+      HeaderEntry header = headers.next();
+      m_connection.setRequestProperty(header.key, header.value);
     }
   }
 
@@ -185,22 +186,6 @@ public class HttpClient {
   private static final String ANDROID_DEVICE_CLASS_PC = "Android.PC";
   private static final String ANDROID_DEVICE_CLASS_PHONE = "Android.Phone";
 
-  static Map<String, String> convertHeaders(
-          int[] header_length,
-          byte[] header_buffer
-  ) {
-    int offset = 0;
-    Map<String, String> result = new HashMap<>(header_length.length);
-    for (int i = 0; i + 1 < header_length.length; i += 2) {
-      String k = new String(header_buffer, offset, header_length[i], UTF_8);
-      offset += header_length[i];
-      String v = new String(header_buffer, offset, header_length[i + 1], UTF_8);
-      offset += header_length[i + 1];
-      result.put(k, v);
-    }
-    return result;
-  }
-
   /** Shim FutureTask: we would like to @Keep the cancel method for JNI */
   static class FutureShim extends FutureTask<Boolean> {
     FutureShim(HttpClientRequest inner) {
@@ -394,7 +379,7 @@ public FutureTask<Boolean> createTask(
       int[] header_index,
       byte[] header_buffer) {
     try {
-      Map<String, String> headers = HttpClient.convertHeaders(header_index, header_buffer);
+      HttpClientRequest.Headers headers = new HttpClientRequest.Headers(header_index, header_buffer);
       HttpClientRequest r = m_requestFactory.create(this, url, method, body, request_id, headers);
       return new FutureShim(r);
     } catch (Exception e) {

lib/android_build/maesdk/src/main/java/com/microsoft/applications/events/HttpClientRequest.java

@@ -7,7 +7,9 @@
 import androidx.annotation.NonNull;
 
 import java.io.IOException;
-import java.util.Map;
+import java.util.Iterator;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 public interface HttpClientRequest extends Runnable {
 
@@ -18,14 +20,53 @@ HttpClientRequest create(
                 String method,
                 byte[] body,
                 String request_id,
-                @NonNull Map<String, String> headers
+                @NonNull Headers headers
         ) throws IOException;
 
         class AndroidUrlConnection implements HttpClientRequest.Factory {
             @Override
-            public HttpClientRequest create(@NonNull HttpClient parent, String url, String method, byte[] body, String request_id, @NonNull Map<String, String> headers) throws IOException {
+            public HttpClientRequest create(@NonNull HttpClient parent, String url, String method, byte[] body, String request_id, @NonNull Headers headers) throws IOException {
                 return new Request(parent, url, method, body, request_id, headers);
             }
         }
     }
+
+    final class HeaderEntry {
+        public final String key;
+        public final String value;
+
+        public HeaderEntry(String key, String value) {
+            this.key = key;
+            this.value = value;
+        }
+    }
+
+    final class Headers implements Iterator<HeaderEntry> {
+        public final int length;
+        private final int[] header_lengths;
+        private final byte[] buffer;
+        private int current = 0;
+        private int offset = 0;
+
+        public Headers(int[] header_lengths, byte[] buffer) {
+            this.length = header_lengths.length;
+            this.header_lengths = header_lengths;
+            this.buffer = buffer;
+        }
+
+        @Override
+        public boolean hasNext() {
+            return current + 2 <= length;
+        }
+
+        @Override
+        public HeaderEntry next() {
+            String k = new String(buffer, offset, header_lengths[current], UTF_8);
+            offset += header_lengths[current];
+            String v = new String(buffer, offset, header_lengths[current + 1], UTF_8);
+            offset += header_lengths[current + 1];
+            current += 2;
+            return new HeaderEntry(k,v);
+        }
+    }
 }