Refactoring

app/src/main/java/eu/faircode/email/HtmlHelper.java

@@ -19,6 +19,15 @@ package eu.faircode.email;
     Copyright 2018 by Marcel Bokhorst (M66B)
 */
 
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
+import android.text.TextUtils;
+import android.util.Base64;
+import android.util.Log;
+
 import org.jsoup.Jsoup;
 import org.jsoup.nodes.Document;
 import org.jsoup.nodes.Element;
@@ -28,6 +37,12 @@ import org.jsoup.safety.Whitelist;
 import org.jsoup.select.NodeTraversor;
 import org.jsoup.select.NodeVisitor;
 
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -82,4 +97,125 @@ public class HtmlHelper {
         }, document.body());
         return document.body().html();
     }
+
+    static Drawable decodeImage(String source, Context context, long id, boolean show) {
+        float scale = context.getResources().getDisplayMetrics().density;
+        int px = Math.round(48 * scale);
+
+        if (TextUtils.isEmpty(source)) {
+            Drawable d = context.getResources().getDrawable(R.drawable.baseline_broken_image_24, context.getTheme());
+            d.setBounds(0, 0, px / 2, px / 2);
+            return d;
+        }
+
+        boolean embedded = source.startsWith("cid:");
+        boolean data = source.startsWith("data:");
+        Log.i(Helper.TAG, "Image embedded=" + embedded + " data=" + data + " source=" + source);
+
+        if (show) {
+            // Embedded images
+            if (embedded) {
+                String cid = "<" + source.split(":")[1] + ">";
+                EntityAttachment attachment = DB.getInstance(context).attachment().getAttachment(id, cid);
+                if (attachment == null || !attachment.available) {
+                    Drawable d = context.getResources().getDrawable(R.drawable.baseline_photo_library_24, context.getTheme());
+                    d.setBounds(0, 0, px, px);
+                    return d;
+                } else {
+                    File file = EntityAttachment.getFile(context, attachment.id);
+                    Drawable d = Drawable.createFromPath(file.getAbsolutePath());
+                    if (d == null) {
+                        d = context.getResources().getDrawable(R.drawable.baseline_broken_image_24, context.getTheme());
+                        d.setBounds(0, 0, px / 2, px / 2);
+                    } else
+                        d.setBounds(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
+                    return d;
+                }
+            }
+
+            // Data URI
+            if (data) {
+                // "<img src=\"data:image/png;base64,iVBORw0KGgoAAA" +
+                // "ANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4" +
+                // "//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU" +
+                // "5ErkJggg==\" alt=\"Red dot\" />";
+
+                String base64 = source.substring(source.indexOf(',') + 1);
+                byte[] bytes = Base64.decode(base64.getBytes(), 0);
+
+                Bitmap bm = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
+                if (bm == null)
+                    throw new IllegalArgumentException("decode byte array failed");
+
+                Drawable d = new BitmapDrawable(context.getResources(), bm);
+                d.setBounds(0, 0, bm.getWidth(), bm.getHeight());
+                return d;
+            }
+
+            // Get cache folder
+            File dir = new File(context.getCacheDir(), "images");
+            if (!dir.exists())
+                dir.mkdir();
+
+            InputStream is = null;
+            FileOutputStream os = null;
+            try {
+                // Create unique file name
+                File file = new File(dir, id + "_" + source.hashCode());
+
+                // Get input stream
+                if (file.exists()) {
+                    Log.i(Helper.TAG, "Using cached " + file);
+                    is = new FileInputStream(file);
+                } else {
+                    Log.i(Helper.TAG, "Downloading " + source);
+                    is = new URL(source).openStream();
+                }
+
+                // Decode image from stream
+                Bitmap bm = BitmapFactory.decodeStream(is);
+                if (bm == null)
+                    throw new IllegalArgumentException("decode stream failed");
+
+                // Cache bitmap
+                if (!file.exists()) {
+                    os = new FileOutputStream(file);
+                    bm.compress(Bitmap.CompressFormat.PNG, 100, os);
+                }
+
+                // Create drawable from bitmap
+                Drawable d = new BitmapDrawable(context.getResources(), bm);
+                d.setBounds(0, 0, bm.getWidth(), bm.getHeight());
+                return d;
+            } catch (Throwable ex) {
+                // Show warning icon
+                Log.e(Helper.TAG, ex + "\n" + Log.getStackTraceString(ex));
+                Drawable d = context.getResources().getDrawable(R.drawable.baseline_broken_image_24, context.getTheme());
+                d.setBounds(0, 0, px / 2, px / 2);
+                return d;
+            } finally {
+                // Close streams
+                if (is != null) {
+                    try {
+                        is.close();
+                    } catch (IOException e) {
+                        Log.w(Helper.TAG, e + "\n" + Log.getStackTraceString(e));
+                    }
+                }
+                if (os != null) {
+                    try {
+                        os.close();
+                    } catch (IOException e) {
+                        Log.w(Helper.TAG, e + "\n" + Log.getStackTraceString(e));
+                    }
+                }
+            }
+        } else {
+            // Show placeholder icon
+            int resid = (embedded || data ? R.drawable.baseline_photo_library_24 : R.drawable.baseline_image_24);
+            Drawable d = context.getResources().getDrawable(resid, context.getTheme());
+            d.setBounds(0, 0, px, px);
+            return d;
+        }
+    }
 }