image-loader Fix data scheme handler

markwon-image-loader/src/main/java/ru/noties/markwon/il/AsyncDrawableLoader.java

@@ -79,6 +79,14 @@ public class AsyncDrawableLoader implements AsyncDrawable.Loader {
         // todo: should we cancel pending request for the same destination?
         //      we _could_ but there is possibility that one resource is request in multiple places
 
+        // todo: error handing (simply applying errorDrawable is not a good solution
+        //      as reason for an error is unclear (no scheme handler, no input data, error decoding, etc)
+
+        // todo: more efficient ImageMediaDecoder... BitmapFactory.decodeStream is a bit not optimal
+        //      for big images for sure. We _could_ introduce internal Drawable that will check for
+        //      image bounds (but we will need to cache inputStream in order to inspect and optimize
+        //      input image...)
+
         // todo, if not a link -> show placeholder
 
         return executorService.submit(new Runnable() {
@@ -176,6 +184,10 @@ public class AsyncDrawableLoader implements AsyncDrawable.Loader {
         return out;
     }
 
+    // todo: as now we have different layers of abstraction (for scheme handling and media decoding)
+    //      we no longer should add dependencies implicitly, it would be way better to allow adding
+    //      multiple artifacts (file, data, network, svg, gif)... at least, maybe we can extract API
+    //      for this module (without implementations), but keep _all-in_ (fat) artifact with all of these.
     public static class Builder {
 
         private OkHttpClient client;

markwon-image-loader/src/main/java/ru/noties/markwon/il/DataUriSchemeHandler.java

@@ -19,6 +19,8 @@ public class DataUriSchemeHandler extends SchemeHandler {
         return new DataUriSchemeHandler(DataUriParser.create(), DataUriDecoder.create());
     }
 
+    private static final String START = "data://";
+
     private final DataUriParser uriParser;
     private final DataUriDecoder uriDecoder;
 
@@ -32,12 +34,12 @@ public class DataUriSchemeHandler extends SchemeHandler {
     @Override
     public ImageItem handle(@NonNull String raw, @NonNull Uri uri) {
 
-        final String part = uri.getSchemeSpecificPart();
-
-        if (TextUtils.isEmpty(part)) {
+        if (!raw.startsWith(START)) {
             return null;
         }
 
+        final String part = raw.substring(START.length());
+
         final DataUri dataUri = uriParser.parse(part);
         if (dataUri == null) {
             return null;

markwon-image-loader/src/main/java/ru/noties/markwon/il/SchemeHandler.java

@@ -16,6 +16,10 @@ public abstract class SchemeHandler {
 
     public abstract void cancel(@NonNull String raw);
 
+    /**
+     * Will be called only once during initialization, should return schemes that are
+     * handled by this handler
+     */
     @NonNull
     public abstract Collection<String> schemes();
 }

markwon-image-loader/src/test/java/ru/noties/markwon/il/DataUriSchemeHandlerTest.java

@@ -0,0 +1,85 @@
+package ru.noties.markwon.il;
+
+import android.net.Uri;
+import android.support.annotation.NonNull;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+
+import java.io.InputStream;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Scanner;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+@RunWith(RobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class DataUriSchemeHandlerTest {
+
+    private DataUriSchemeHandler handler;
+
+    @Before
+    public void before() {
+        handler = DataUriSchemeHandler.create();
+    }
+
+    @Test
+    public void scheme_specific_part_is_empty() {
+        assertNull(handler.handle("data:", Uri.parse("data:")));
+    }
+
+    @Test
+    public void data_uri_is_empty() {
+        assertNull(handler.handle("data://whatever", Uri.parse("data://whatever")));
+    }
+
+    @Test
+    public void no_data() {
+        assertNull(handler.handle("data://,", Uri.parse("data://,")));
+    }
+
+    @Test
+    public void correct() {
+
+        final class Item {
+
+            final String contentType;
+            final String data;
+
+            Item(String contentType, String data) {
+                this.contentType = contentType;
+                this.data = data;
+            }
+        }
+
+        final Map<String, Item> expected = new HashMap<String, Item>() {{
+            put("data://text/plain;,123", new Item("text/plain", "123"));
+            put("data://image/svg+xml;base64,MTIz", new Item("image/svg+xml", "123"));
+        }};
+
+        for (Map.Entry<String, Item> entry : expected.entrySet()) {
+            final ImageItem item = handler.handle(entry.getKey(), Uri.parse(entry.getKey()));
+            assertNotNull(entry.getKey(), item);
+            assertEquals(entry.getKey(), entry.getValue().contentType, item.contentType());
+            assertEquals(entry.getKey(), entry.getValue().data, readStream(item.inputStream()));
+        }
+    }
+
+    @NonNull
+    private static String readStream(@NonNull InputStream stream) {
+        try {
+            final Scanner scanner = new Scanner(stream, "UTF-8").useDelimiter("\\A");
+            return scanner.hasNext()
+                    ? scanner.next()
+                    : "";
+        } catch (Throwable t) {
+            throw new RuntimeException(t);
+        }
+    }
+}