1 files changed, 283 insertions, 0 deletions
diff --git a/core/src/main/java/com/android/volley/toolbox/ImageRequest.java b/core/src/main/java/com/android/volley/toolbox/ImageRequest.java
new file mode 100644
index 0000000..32b5aa3
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+++ b/core/src/main/java/com/android/volley/toolbox/ImageRequest.java
@@ -0,0 +1,283 @@
+/*
+ * Copyright (C) 2011 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 com.android.volley.toolbox;
+
+import android.graphics.Bitmap;
+import android.graphics.Bitmap.Config;
+import android.graphics.BitmapFactory;
+import android.widget.ImageView.ScaleType;
+import androidx.annotation.GuardedBy;
+import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
+import com.android.volley.DefaultRetryPolicy;
+import com.android.volley.NetworkResponse;
+import com.android.volley.ParseError;
+import com.android.volley.Request;
+import com.android.volley.Response;
+import com.android.volley.VolleyLog;
+
+/** A canned request for getting an image at a given URL and calling back with a decoded Bitmap. */
+public class ImageRequest extends Request<Bitmap> {
+    /** Socket timeout in milliseconds for image requests */
+    public static final int DEFAULT_IMAGE_TIMEOUT_MS = 1000;
+
+    /** Default number of retries for image requests */
+    public static final int DEFAULT_IMAGE_MAX_RETRIES = 2;
+
+    /** Default backoff multiplier for image requests */
+    public static final float DEFAULT_IMAGE_BACKOFF_MULT = 2f;
+
+    /** Lock to guard mListener as it is cleared on cancel() and read on delivery. */
+    private final Object mLock = new Object();
+
+    @GuardedBy("mLock")
+    @Nullable
+    private Response.Listener<Bitmap> mListener;
+
+    private final Config mDecodeConfig;
+    private final int mMaxWidth;
+    private final int mMaxHeight;
+    private final ScaleType mScaleType;
+
+    /** Decoding lock so that we don't decode more than one image at a time (to avoid OOM's) */
+    private static final Object sDecodeLock = new Object();
+
+    /**
+     * Creates a new image request, decoding to a maximum specified width and height. If both width
+     * and height are zero, the image will be decoded to its natural size. If one of the two is
+     * nonzero, that dimension will be clamped and the other one will be set to preserve the image's
+     * aspect ratio. If both width and height are nonzero, the image will be decoded to be fit in
+     * the rectangle of dimensions width x height while keeping its aspect ratio.
+     *
+     * @param url URL of the image
+     * @param listener Listener to receive the decoded bitmap
+     * @param maxWidth Maximum width to decode this bitmap to, or zero for none
+     * @param maxHeight Maximum height to decode this bitmap to, or zero for none
+     * @param scaleType The ImageViews ScaleType used to calculate the needed image size.
+     * @param decodeConfig Format to decode the bitmap to
+     * @param errorListener Error listener, or null to ignore errors
+     */
+    public ImageRequest(
+            String url,
+            Response.Listener<Bitmap> listener,
+            int maxWidth,
+            int maxHeight,
+            ScaleType scaleType,
+            Config decodeConfig,
+            @Nullable Response.ErrorListener errorListener) {
+        super(Method.GET, url, errorListener);
+        setRetryPolicy(
+                new DefaultRetryPolicy(
+                        DEFAULT_IMAGE_TIMEOUT_MS,
+                        DEFAULT_IMAGE_MAX_RETRIES,
+                        DEFAULT_IMAGE_BACKOFF_MULT));
+        mListener = listener;
+        mDecodeConfig = decodeConfig;
+        mMaxWidth = maxWidth;
+        mMaxHeight = maxHeight;
+        mScaleType = scaleType;
+    }
+
+    /**
+     * For API compatibility with the pre-ScaleType variant of the constructor. Equivalent to the
+     * normal constructor with {@code ScaleType.CENTER_INSIDE}.
+     */
+    @Deprecated
+    public ImageRequest(
+            String url,
+            Response.Listener<Bitmap> listener,
+            int maxWidth,
+            int maxHeight,
+            Config decodeConfig,
+            Response.ErrorListener errorListener) {
+        this(
+                url,
+                listener,
+                maxWidth,
+                maxHeight,
+                ScaleType.CENTER_INSIDE,
+                decodeConfig,
+                errorListener);
+    }
+
+    @Override
+    public Priority getPriority() {
+        return Priority.LOW;
+    }
+
+    /**
+     * Scales one side of a rectangle to fit aspect ratio.
+     *
+     * @param maxPrimary Maximum size of the primary dimension (i.e. width for max width), or zero
+     *     to maintain aspect ratio with secondary dimension
+     * @param maxSecondary Maximum size of the secondary dimension, or zero to maintain aspect ratio
+     *     with primary dimension
+     * @param actualPrimary Actual size of the primary dimension
+     * @param actualSecondary Actual size of the secondary dimension
+     * @param scaleType The ScaleType used to calculate the needed image size.
+     */
+    private static int getResizedDimension(
+            int maxPrimary,
+            int maxSecondary,
+            int actualPrimary,
+            int actualSecondary,
+            ScaleType scaleType) {
+
+        // If no dominant value at all, just return the actual.
+        if ((maxPrimary == 0) && (maxSecondary == 0)) {
+            return actualPrimary;
+        }
+
+        // If ScaleType.FIT_XY fill the whole rectangle, ignore ratio.
+        if (scaleType == ScaleType.FIT_XY) {
+            if (maxPrimary == 0) {
+                return actualPrimary;
+            }
+            return maxPrimary;
+        }
+
+        // If primary is unspecified, scale primary to match secondary's scaling ratio.
+        if (maxPrimary == 0) {
+            double ratio = (double) maxSecondary / (double) actualSecondary;
+            return (int) (actualPrimary * ratio);
+        }
+
+        if (maxSecondary == 0) {
+            return maxPrimary;
+        }
+
+        double ratio = (double) actualSecondary / (double) actualPrimary;
+        int resized = maxPrimary;
+
+        // If ScaleType.CENTER_CROP fill the whole rectangle, preserve aspect ratio.
+        if (scaleType == ScaleType.CENTER_CROP) {
+            if ((resized * ratio) < maxSecondary) {
+                resized = (int) (maxSecondary / ratio);
+            }
+            return resized;
+        }
+
+        if ((resized * ratio) > maxSecondary) {
+            resized = (int) (maxSecondary / ratio);
+        }
+        return resized;
+    }
+
+    @Override
+    protected Response<Bitmap> parseNetworkResponse(NetworkResponse response) {
+        // Serialize all decode on a global lock to reduce concurrent heap usage.
+        synchronized (sDecodeLock) {
+            try {
+                return doParse(response);
+            } catch (OutOfMemoryError e) {
+                VolleyLog.e("Caught OOM for %d byte image, url=%s", response.data.length, getUrl());
+                return Response.error(new ParseError(e));
+            }
+        }
+    }
+
+    /** The real guts of parseNetworkResponse. Broken out for readability. */
+    private Response<Bitmap> doParse(NetworkResponse response) {
+        byte[] data = response.data;
+        BitmapFactory.Options decodeOptions = new BitmapFactory.Options();
+        Bitmap bitmap = null;
+        if (mMaxWidth == 0 && mMaxHeight == 0) {
+            decodeOptions.inPreferredConfig = mDecodeConfig;
+            bitmap = BitmapFactory.decodeByteArray(data, 0, data.length, decodeOptions);
+        } else {
+            // If we have to resize this image, first get the natural bounds.
+            decodeOptions.inJustDecodeBounds = true;
+            BitmapFactory.decodeByteArray(data, 0, data.length, decodeOptions);
+            int actualWidth = decodeOptions.outWidth;
+            int actualHeight = decodeOptions.outHeight;
+
+            // Then compute the dimensions we would ideally like to decode to.
+            int desiredWidth =
+                    getResizedDimension(
+                            mMaxWidth, mMaxHeight, actualWidth, actualHeight, mScaleType);
+            int desiredHeight =
+                    getResizedDimension(
+                            mMaxHeight, mMaxWidth, actualHeight, actualWidth, mScaleType);
+
+            // Decode to the nearest power of two scaling factor.
+            decodeOptions.inJustDecodeBounds = false;
+            // TODO(ficus): Do we need this or is it okay since API 8 doesn't support it?
+            // decodeOptions.inPreferQualityOverSpeed = PREFER_QUALITY_OVER_SPEED;
+            decodeOptions.inSampleSize =
+                    findBestSampleSize(actualWidth, actualHeight, desiredWidth, desiredHeight);
+            Bitmap tempBitmap = BitmapFactory.decodeByteArray(data, 0, data.length, decodeOptions);
+
+            // If necessary, scale down to the maximal acceptable size.
+            if (tempBitmap != null
+                    && (tempBitmap.getWidth() > desiredWidth
+                            || tempBitmap.getHeight() > desiredHeight)) {
+                bitmap = Bitmap.createScaledBitmap(tempBitmap, desiredWidth, desiredHeight, true);
+                tempBitmap.recycle();
+            } else {
+                bitmap = tempBitmap;
+            }
+        }
+
+        if (bitmap == null) {
+            return Response.error(new ParseError(response));
+        } else {
+            return Response.success(bitmap, HttpHeaderParser.parseCacheHeaders(response));
+        }
+    }
+
+    @Override
+    public void cancel() {
+        super.cancel();
+        synchronized (mLock) {
+            mListener = null;
+        }
+    }
+
+    @Override
+    protected void deliverResponse(Bitmap response) {
+        Response.Listener<Bitmap> listener;
+        synchronized (mLock) {
+            listener = mListener;
+        }
+        if (listener != null) {
+            listener.onResponse(response);
+        }
+    }
+
+    /**
+     * Returns the largest power-of-two divisor for use in downscaling a bitmap that will not result
+     * in the scaling past the desired dimensions.
+     *
+     * @param actualWidth Actual width of the bitmap
+     * @param actualHeight Actual height of the bitmap
+     * @param desiredWidth Desired width of the bitmap
+     * @param desiredHeight Desired height of the bitmap
+     */
+    @VisibleForTesting
+    static int findBestSampleSize(
+            int actualWidth, int actualHeight, int desiredWidth, int desiredHeight) {
+        double wr = (double) actualWidth / desiredWidth;
+        double hr = (double) actualHeight / desiredHeight;
+        double ratio = Math.min(wr, hr);
+        float n = 1.0f;
+        while ((n * 2) <= ratio) {
+            n *= 2;
+        }
+
+        return (int) n;
+    }
+}