Merge branch 'mrschmidt/bundle/reader' into mrschmidt/bundle/localstore

Author: schmidt-sebastian

firebase-firestore/src/main/java/com/google/firebase/firestore/bundle/BundleDocument.java

@@ -18,7 +18,7 @@
 import com.google.firebase.firestore.model.DocumentKey;
 
 /** A document that was saved to a bundle. */
-public class BundleDocument extends BundleElement {
+public class BundleDocument implements BundleElement {
   private Document document;
 
   public BundleDocument(Document document) {

firebase-firestore/src/main/java/com/google/firebase/firestore/bundle/BundleElement.java

@@ -14,27 +14,4 @@
 
 package com.google.firebase.firestore.bundle;
 
-import org.json.JSONException;
-import org.json.JSONObject;
-
-public abstract class BundleElement {
-
-  public static BundleElement fromJson(BundleSerializer serializer, String json)
-      throws JSONException {
-    JSONObject object = new JSONObject(json);
-
-    if (object.has("metadata")) {
-      return serializer.decodeBundleMetadata(object.getJSONObject("metadata"));
-    } else if (object.has("namedQuery")) {
-      return serializer.decodeNamedQuery(object.getJSONObject("namedQuery"));
-    } else if (object.has("documentMetadata")) {
-      return serializer.decodeBundledDocumentMetadata(object.getJSONObject("documentMetadata"));
-    } else if (object.has("document")) {
-      return serializer.decodeDocument(object.getJSONObject("document"));
-    } else {
-      throw new IllegalArgumentException("Cannot decode unknown Bundle element: " + json);
-    }
-  }
-
-  protected BundleElement() {}
-}
+public interface BundleElement {}

firebase-firestore/src/main/java/com/google/firebase/firestore/bundle/BundleMetadata.java

@@ -17,7 +17,7 @@
 import com.google.firebase.firestore.model.SnapshotVersion;
 
 /** Represents a Firestore bundle saved by the SDK in its local storage. */
-public class BundleMetadata extends BundleElement {
+public class BundleMetadata implements BundleElement {
   private final String bundleId;
   private final int version;
   private final SnapshotVersion createTime;

firebase-firestore/src/main/java/com/google/firebase/firestore/bundle/BundleReader.java

@@ -19,15 +19,17 @@
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.nio.CharBuffer;
+import java.nio.charset.Charset;
 import org.json.JSONException;
+import org.json.JSONObject;
 
 /**
  * Reads the length-prefixed JSON stream for Bundles.
  *
  * <p>The class takes a bundle stream and presents abstractions to read bundled elements out of the
  * underlying content.
  */
-public class BundleReader extends BundleElement {
+public class BundleReader {
   /** The capacity for the internal char buffer. */
   protected static final int BUFFER_CAPACITY = 1024;
 
@@ -40,8 +42,10 @@ public class BundleReader extends BundleElement {
 
   public BundleReader(BundleSerializer serializer, InputStream data) {
     this.serializer = serializer;
-    dataReader = new InputStreamReader(data);
+    dataReader = new InputStreamReader(data, Charset.forName("UTF-8"));
     buffer = CharBuffer.allocate(BUFFER_CAPACITY);
+
+    buffer.flip(); // Start the buffer in "reading mode"
   }
 
   /** Returns the metadata element from the bundle. */
@@ -91,23 +95,23 @@ public void close() throws IOException {
    */
   @Nullable
   private BundleElement readNextElement() throws IOException, JSONException {
-    int length = readLength();
-    if (length == -1) {
+    String lengthPrefix = readLengthPrefix();
+    if (lengthPrefix == null) {
       return null;
     }
 
-    String json = readJsonString(length);
-    bytesRead += (int) (Math.log10(length) + 1) + length;
-    return BundleElement.fromJson(serializer, json);
+    String json = readJsonString(Integer.parseInt(lengthPrefix));
+    bytesRead += lengthPrefix.length() + json.length();
+    return decodeBundleElement(json);
   }
 
   /**
    * Reads the length prefix from the beginning of the internal buffer until the first '{'. Returns
    * the integer-decoded length.
    *
-   * <p>If it reached the end of the stream, returns -1.
+   * <p>If it reached the end of the stream, returns null.
    */
-  private int readLength() throws IOException {
+  private @Nullable String readLengthPrefix() throws IOException {
     int nextOpenBracket;
 
     while ((nextOpenBracket = indexOfOpenBracket()) == -1) {
@@ -119,7 +123,7 @@ private int readLength() throws IOException {
     // We broke out of the loop because underlying stream is closed, and there happens to be no
     // more data to process.
     if (buffer.remaining() == 0) {
-      return -1;
+      return null;
     }
 
     // We broke out of the loop because underlying stream is closed, but still cannot find an
@@ -130,14 +134,14 @@ private int readLength() throws IOException {
 
     char[] c = new char[nextOpenBracket];
     buffer.get(c);
-    return Integer.parseInt(new String(c));
+    return new String(c);
   }
 
   /** Returns the index of the first open bracket, or -1 if none is found. */
   private int indexOfOpenBracket() {
     buffer.mark();
     try {
-      for (int i = 0; i < buffer.limit(); ++i) {
+      for (int i = 0; i < buffer.remaining(); ++i) {
         if (buffer.get() == '{') {
           return i;
         }
@@ -155,20 +159,22 @@ private int indexOfOpenBracket() {
    * <p>Returns a string decoded from the read bytes.
    */
   private String readJsonString(int length) throws IOException {
-    char[] c = new char[length];
+    StringBuilder json = new StringBuilder();
 
-    int read = Math.min(length, buffer.remaining());
-    buffer.get(c, 0, read);
-
-    while (read < length) {
+    int remaining = length;
+    while (remaining > 0) {
       if (!pullMoreData()) {
         raiseError("Reached the end of bundle when more data was expected.");
       }
-      int toRead = Math.min(length, buffer.remaining());
-      buffer.get(c, read, toRead);
-      read += toRead;
+
+      int read = Math.min(remaining, buffer.remaining());
+      json.append(buffer, 0, read);
+      buffer.position(buffer.position() + read);
+
+      remaining -= read;
     }
-    return new String(c);
+
+    return json.toString();
   }
 
   /**
@@ -179,17 +185,29 @@ private String readJsonString(int length) throws IOException {
   private boolean pullMoreData() throws IOException {
     if (buffer.remaining() == 0) {
       buffer.compact();
+      dataReader.read(buffer);
+      buffer.flip();
     }
-
-    int read;
-    do {
-      read = dataReader.read(buffer);
-    } while (read > 0);
-    buffer.flip();
-
     return buffer.remaining() > 0;
   }
 
+  /** Converts a JSON-encoded bundle element into its model class. */
+  private BundleElement decodeBundleElement(String json) throws JSONException {
+    JSONObject object = new JSONObject(json);
+
+    if (object.has("metadata")) {
+      return serializer.decodeBundleMetadata(object.getJSONObject("metadata"));
+    } else if (object.has("namedQuery")) {
+      return serializer.decodeNamedQuery(object.getJSONObject("namedQuery"));
+    } else if (object.has("documentMetadata")) {
+      return serializer.decodeBundledDocumentMetadata(object.getJSONObject("documentMetadata"));
+    } else if (object.has("document")) {
+      return serializer.decodeDocument(object.getJSONObject("document"));
+    } else {
+      throw new IllegalArgumentException("Cannot decode unknown Bundle element: " + json);
+    }
+  }
+
   /** Closes the underlying stream and raises an IllegalArgumentException. */
   private void raiseError(String message) throws IOException {
     close();

firebase-firestore/src/main/java/com/google/firebase/firestore/bundle/BundledDocumentMetadata.java

@@ -21,7 +21,7 @@
 // TODO(bundles): Figure out whether we need this class (it is not needed in Web).
 
 /** Metadata describing a Firestore document saved in the bundle. */
-public class BundledDocumentMetadata extends BundleElement {
+public class BundledDocumentMetadata implements BundleElement {
   private final DocumentKey key;
   private final SnapshotVersion readTime;
   private final boolean exists;

firebase-firestore/src/main/java/com/google/firebase/firestore/bundle/BundledQuery.java

@@ -18,7 +18,7 @@
 import com.google.firebase.firestore.core.Target;
 
 /** A bundled query represents a query target and its limit. */
-public class BundledQuery extends BundleElement {
+public class BundledQuery implements BundleElement {
   private final Target target;
   private final Query.LimitType limitType;
 

firebase-firestore/src/main/java/com/google/firebase/firestore/bundle/NamedQuery.java

@@ -17,7 +17,7 @@
 import com.google.firebase.firestore.model.SnapshotVersion;
 
 /** Represents a named query saved by the SDK in its local storage. */
-public class NamedQuery extends BundleElement {
+public class NamedQuery implements BundleElement {
   private final String name;
   private final BundledQuery bundledQuery;
   private final SnapshotVersion readTime;