Sardine: Add additional "put" method (with lock token)

src/main/java/com/thegrizzlylabs/sardineandroid/Sardine.java

@@ -280,6 +280,20 @@ public interface Sardine
 	 */
 	void put(String url, File localFile, String contentType, boolean expectContinue) throws IOException;
 
+
+	/**
+	 * Uses <code>PUT</code> to upload file to a server with specific contentType.
+	 * Repeatable on authentication failure.
+	 *
+	 * @param url		Path to the resource including protocol and hostname
+	 * @param localFile local file to send
+	 * @param contentType	MIME type to add to the HTTP request header
+	 * @param expectContinue Enable <code>Expect: continue</code> header for <code>PUT</code> requests.
+	 * @param lockToken A lock token is a type of state token that identifies a particular lock.
+	 * @throws IOException I/O error or HTTP response validation failure
+	 */
+	void put(String url, File localFile, String contentType, boolean expectContinue, String lockToken) throws IOException;
+
 	/**
 	 * Delete a resource using HTTP <code>DELETE</code> at the specified url
 	 *

src/main/java/com/thegrizzlylabs/sardineandroid/impl/OkHttpSardine.java

@@ -1,5 +1,7 @@
 package com.thegrizzlylabs.sardineandroid.impl;
 
+import android.text.TextUtils;
+
 import com.thegrizzlylabs.sardineandroid.DavAce;
 import com.thegrizzlylabs.sardineandroid.DavAcl;
 import com.thegrizzlylabs.sardineandroid.DavPrincipal;
@@ -302,12 +304,20 @@ public void put(String url, File localFile, String contentType) throws IOExcepti
 
     @Override
     public void put(String url, File localFile, String contentType, boolean expectContinue) throws IOException {
+        put(url, localFile, contentType, expectContinue, null);
+    }
+
+    @Override
+    public void put(String url, File localFile, String contentType, boolean expectContinue, String lockToken) throws IOException {
         MediaType mediaType = contentType == null ? null : MediaType.parse(contentType);
         RequestBody requestBody = RequestBody.create(mediaType, localFile);
         Headers.Builder headersBuilder = new Headers.Builder();
         if (expectContinue) {
             headersBuilder.add("Expect", "100-Continue");
         }
+        if (!TextUtils.isEmpty(lockToken)) {
+            headersBuilder.add("If", "<" + url + "> (<" + lockToken + ">)");
+        }
         put(url, requestBody, headersBuilder.build());
     }