WIP mime parsing

8 files changed, 610 insertions, 42 deletions

diff --git a/OpenKeychain/build.gradle b/OpenKeychain/build.gradle
index 7d2f40128..5bf8f6d1b 100644
--- a/OpenKeychain/build.gradle
+++ b/OpenKeychain/build.gradle
@@ -56,6 +56,8 @@ dependencies {
     compile 'com.mikepenz.iconics:community-material-typeface:1.0.0@aar'
     compile 'com.nispok:snackbar:2.11.0'
     compile 'com.squareup.okhttp:okhttp:2.4.0'
+    compile 'org.apache.james:apache-mime4j-core:0.7.2'
+    compile 'org.apache.james:apache-mime4j-dom:0.7.2'
 
     // libs as submodules
     compile project(':extern:openpgp-api-lib:openpgp-api')
@@ -199,15 +201,21 @@ android {
         htmlOutput file('lint-report.html')
     }
 
-    // Disable preDexing, causes com.android.dx.cf.iface.ParseException: bad class file magic (cafebabe) or version (0034.0000) on some systems
     dexOptions {
+        // Disable preDexing, causes com.android.dx.cf.iface.ParseException: bad class file magic (cafebabe) or version (0034.0000) on some systems
         preDexLibraries = false
+        // faster with incremental?
+//        incremental true
+        javaMaxHeapSize "4g"
     }
 
     packagingOptions {
         exclude 'LICENSE.txt'
         exclude 'META-INF/LICENSE.txt'
         exclude 'META-INF/NOTICE.txt'
+        exclude 'META-INF/DEPENDENCIES'
+        exclude 'META-INF/LICENSE'
+        exclude 'META-INF/NOTICE'
         exclude '.readme'
     }
 }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/MimeParsingOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/MimeParsingOperation.java
new file mode 100644
index 000000000..c7ebbf5fd
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/MimeParsingOperation.java
@@ -0,0 +1,360 @@
+/*
+ * Copyright (C) 2015 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.operations;
+
+import android.content.Context;
+import android.net.Uri;
+import android.support.annotation.NonNull;
+
+import org.apache.james.mime4j.dom.BinaryBody;
+import org.apache.james.mime4j.dom.Body;
+import org.apache.james.mime4j.dom.Entity;
+import org.apache.james.mime4j.dom.Message;
+import org.apache.james.mime4j.dom.MessageBuilder;
+import org.apache.james.mime4j.dom.Multipart;
+import org.apache.james.mime4j.dom.TextBody;
+import org.apache.james.mime4j.dom.address.Mailbox;
+import org.apache.james.mime4j.dom.address.MailboxList;
+import org.apache.james.mime4j.dom.field.AddressListField;
+import org.apache.james.mime4j.dom.field.ContentTypeField;
+import org.apache.james.mime4j.dom.field.DateTimeField;
+import org.apache.james.mime4j.dom.field.UnstructuredField;
+import org.apache.james.mime4j.field.address.AddressFormatter;
+import org.apache.james.mime4j.message.BodyPart;
+import org.apache.james.mime4j.message.DefaultMessageBuilder;
+import org.apache.james.mime4j.message.MessageImpl;
+import org.apache.james.mime4j.stream.Field;
+import org.sufficientlysecure.keychain.Constants;
+import org.sufficientlysecure.keychain.operations.results.MimeParsingResult;
+import org.sufficientlysecure.keychain.operations.results.OperationResult;
+import org.sufficientlysecure.keychain.pgp.Progressable;
+import org.sufficientlysecure.keychain.provider.ProviderHelper;
+import org.sufficientlysecure.keychain.provider.TemporaryStorageProvider;
+import org.sufficientlysecure.keychain.service.MimeParsingParcel;
+import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
+import org.sufficientlysecure.keychain.util.Log;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.Reader;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.Map;
+
+public class MimeParsingOperation extends BaseOperation<MimeParsingParcel> {
+
+    public ArrayList<Uri> mTempUris;
+
+    public MimeParsingOperation(Context context, ProviderHelper providerHelper, Progressable progressable) {
+        super(context, providerHelper, progressable);
+    }
+
+    @NonNull
+    @Override
+    public MimeParsingResult execute(MimeParsingParcel parcel,
+                                     CryptoInputParcel cryptoInputParcel) {
+        OperationResult.OperationLog log = new OperationResult.OperationLog();
+
+        log.add(OperationResult.LogType.MSG_MIME_PARSING, 0);
+
+        mTempUris = new ArrayList<>();
+
+        try {
+            InputStream in = mContext.getContentResolver().openInputStream(parcel.getInputUri());
+
+            final MessageBuilder builder = new DefaultMessageBuilder();
+            final Message message = builder.parseMessage(in);
+
+            SimpleTreeNode root = createNode(message);
+
+            traverseTree(root);
+
+            log.add(OperationResult.LogType.MSG_MIME_PARSING_SUCCESS, 1);
+
+        } catch (Exception e) {
+            Log.e(Constants.TAG, "Mime parsing error", e);
+            log.add(OperationResult.LogType.MSG_MIME_PARSING_ERROR, 1);
+        }
+
+        return new MimeParsingResult(MimeParsingResult.RESULT_OK, log,
+                mTempUris);
+    }
+
+    private void traverseTree(SimpleTreeNode node) {
+        if (node.isLeaf()) {
+            parseAndSaveAsUris(node);
+            return;
+        }
+
+        for (SimpleTreeNode child : node.children) {
+            traverseTree(child);
+        }
+    }
+
+
+    /**
+     * Wraps an Object and associates it with a text. All message parts
+     * (headers, bodies, multiparts, body parts) will be wrapped in
+     * ObjectWrapper instances before they are added to the JTree instance.
+     */
+    public static class ObjectWrapper {
+        private String text = "";
+        private Object object = null;
+
+        public ObjectWrapper(String text, Object object) {
+            this.text = text;
+            this.object = object;
+        }
+
+        @Override
+        public String toString() {
+            return text;
+        }
+
+        public Object getObject() {
+            return object;
+        }
+    }
+
+//    /**
+//     * Create a node given a Multipart body.
+//     * Add the Preamble, all Body parts and the Epilogue to the node.
+//     *
+//     * @return the root node of the tree.
+//     */
+//    private DefaultMutableTreeNode createNode(Header header) {
+//        DefaultMutableTreeNode node = new DefaultMutableTreeNode(
+//                new ObjectWrapper("Header", header));
+//
+//        for (Field field : header.getFields()) {
+//            String name = field.getName();
+//
+//            node.add(new DefaultMutableTreeNode(new ObjectWrapper(name, field)));
+//        }
+//
+//        return node;
+//    }
+
+    /**
+     * Create a node given a Multipart body.
+     * Add the Preamble, all Body parts and the Epilogue to the node.
+     *
+     * @param multipart the Multipart.
+     * @return the root node of the tree.
+     */
+    private SimpleTreeNode createNode(Multipart multipart) {
+        SimpleTreeNode node = new SimpleTreeNode(
+                new ObjectWrapper("Multipart", multipart));
+
+//        node.add(new DefaultMutableTreeNode(
+//                new ObjectWrapper("Preamble", multipart.getPreamble())));
+        for (Entity part : multipart.getBodyParts()) {
+            node.add(createNode(part));
+        }
+//        node.add(new DefaultMutableTreeNode(
+//                new ObjectWrapper("Epilogue", multipart.getEpilogue())));
+
+        return node;
+    }
+
+    /**
+     * Creates the tree nodes given a MIME entity (either a Message or
+     * a BodyPart).
+     *
+     * @param entity the entity.
+     * @return the root node of the tree displaying the specified entity and
+     * its children.
+     */
+    private SimpleTreeNode createNode(Entity entity) {
+
+        /*
+         * Create the root node for the entity. It's either a
+         * Message or a Body part.
+         */
+        String type = "Message";
+        if (entity instanceof BodyPart) {
+            type = "Body part";
+        }
+        SimpleTreeNode node = new SimpleTreeNode(
+                new ObjectWrapper(type, entity));
+
+        /*
+         * Add the node encapsulating the entity Header.
+         */
+//        node.add(createNode(entity.getHeader()));
+
+        Body body = entity.getBody();
+
+        if (body instanceof Multipart) {
+            /*
+             * The body of the entity is a Multipart.
+             */
+
+            node.add(createNode((Multipart) body));
+        } else if (body instanceof MessageImpl) {
+            /*
+             * The body is another Message.
+             */
+
+            node.add(createNode((MessageImpl) body));
+
+        } else {
+            /*
+             * Discrete Body (either of type TextBody or BinaryBody).
+             */
+            type = "Text body";
+            if (body instanceof BinaryBody) {
+                type = "Binary body";
+            }
+
+            type += " (" + entity.getMimeType() + ")";
+            node.add(new SimpleTreeNode(new ObjectWrapper(type, body)));
+
+        }
+
+        return node;
+    }
+
+    public void parseAndSaveAsUris(SimpleTreeNode node) {
+        Object o = ((ObjectWrapper) node.getUserObject()).getObject();
+
+        if (o instanceof TextBody) {
+            /*
+             * A text body. Display its contents.
+             */
+            TextBody body = (TextBody) o;
+            StringBuilder sb = new StringBuilder();
+            try {
+                Reader r = body.getReader();
+                int c;
+                while ((c = r.read()) != -1) {
+                    sb.append((char) c);
+                }
+            } catch (IOException ex) {
+                ex.printStackTrace();
+            }
+            Log.d(Constants.TAG, "text: " + sb.toString());
+//                textView.setText(sb.toString());
+
+            Uri tempUri = null;
+            try {
+                tempUri = TemporaryStorageProvider.createFile(mContext, "text", "text/plain");
+                OutputStream outStream = mContext.getContentResolver().openOutputStream(tempUri);
+                body.writeTo(outStream);
+                outStream.close();
+            } catch (IOException e) {
+                Log.e(Constants.TAG, "error mime parsing", e);
+            }
+
+            mTempUris.add(tempUri);
+
+        } else if (o instanceof BinaryBody) {
+            /*
+             * A binary body. Display its MIME type and length in bytes.
+             */
+            BinaryBody body = (BinaryBody) o;
+            int size = 0;
+            try {
+                InputStream is = body.getInputStream();
+                while ((is.read()) != -1) {
+                    size++;
+                }
+            } catch (IOException ex) {
+                ex.printStackTrace();
+            }
+            Log.d(Constants.TAG, "Binary body\n"
+                    + "MIME type: "
+                    + body.getParent().getMimeType() + "\n"
+                    + "Size of decoded data: " + size + " bytes");
+
+        } else if (o instanceof ContentTypeField) {
+            /*
+             * Content-Type field.
+             */
+            ContentTypeField field = (ContentTypeField) o;
+            StringBuilder sb = new StringBuilder();
+            sb.append("MIME type: ").append(field.getMimeType()).append("\n");
+            for (Map.Entry<String, String> entry : field.getParameters().entrySet()) {
+                sb.append(entry.getKey()).append(" = ").append(entry.getValue()).append("\n");
+            }
+            Log.d(Constants.TAG, sb.toString());
+
+        } else if (o instanceof AddressListField) {
+            /*
+             * An address field (From, To, Cc, etc)
+             */
+            AddressListField field = (AddressListField) o;
+            MailboxList list = field.getAddressList().flatten();
+            StringBuilder sb = new StringBuilder();
+            for (Mailbox mailbox : list) {
+                sb.append(AddressFormatter.DEFAULT.format(mailbox, false)).append("\n");
+            }
+            Log.d(Constants.TAG, sb.toString());
+
+        } else if (o instanceof DateTimeField) {
+            Date date = ((DateTimeField) o).getDate();
+            Log.d(Constants.TAG, date.toString());
+        } else if (o instanceof UnstructuredField) {
+            Log.d(Constants.TAG, ((UnstructuredField) o).getValue());
+        } else if (o instanceof Field) {
+            Log.d(Constants.TAG, ((Field) o).getBody());
+        } else {
+            /*
+             * The Object should be a Header or a String containing a
+             * Preamble or Epilogue.
+             */
+            Log.d(Constants.TAG, o.toString());
+        }
+    }
+
+    public class SimpleTreeNode {
+        private SimpleTreeNode parent;
+        private Object userObject;
+        private ArrayList<SimpleTreeNode> children;
+
+        protected SimpleTreeNode(Object userObject) {
+            this.parent = null;
+            this.userObject = userObject;
+            this.children = new ArrayList<>();
+        }
+
+        protected Object getUserObject() {
+            return userObject;
+        }
+
+        protected void setUserObject(Object userObject) {
+            this.userObject = userObject;
+        }
+
+        public void add(SimpleTreeNode newChild) {
+            newChild.parent = this;
+            children.add(newChild);
+        }
+
+        public SimpleTreeNode getParent() {
+            return parent;
+        }
+
+        public boolean isLeaf() {
+            return children.isEmpty();
+        }
+
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/MimeParsingResult.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/MimeParsingResult.java
new file mode 100644
index 000000000..05f5125cb
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/MimeParsingResult.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2015 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.operations.results;
+
+import android.net.Uri;
+import android.os.Parcel;
+
+import java.util.ArrayList;
+
+public class MimeParsingResult extends OperationResult {
+
+    public final ArrayList<Uri> mTemporaryUris;
+
+    public ArrayList<Uri> getTemporaryUris() {
+        return mTemporaryUris;
+    }
+
+    public MimeParsingResult(int result, OperationLog log, ArrayList<Uri> temporaryUris) {
+        super(result, log);
+        mTemporaryUris = temporaryUris;
+    }
+
+    protected MimeParsingResult(Parcel in) {
+        super(in);
+        mTemporaryUris = in.createTypedArrayList(Uri.CREATOR);
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        super.writeToParcel(dest, flags);
+        dest.writeTypedList(mTemporaryUris);
+    }
+
+    public static final Creator<MimeParsingResult> CREATOR = new Creator<MimeParsingResult>() {
+        @Override
+        public MimeParsingResult createFromParcel(Parcel in) {
+            return new MimeParsingResult(in);
+        }
+
+        @Override
+        public MimeParsingResult[] newArray(int size) {
+            return new MimeParsingResult[size];
+        }
+    };
+}
\ No newline at end of file
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/OperationResult.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/OperationResult.java
index d498bd9a1..3c15a2e7b 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/OperationResult.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/OperationResult.java
@@ -787,6 +787,11 @@ public abstract class OperationResult implements Parcelable {
         MSG_EXPORT_LOG_EXPORT_ERROR_FOPEN(LogLevel.ERROR,R.string.msg_export_log_error_fopen),
         MSG_EXPORT_LOG_EXPORT_ERROR_WRITING(LogLevel.ERROR,R.string.msg_export_log_error_writing),
         MSG_EXPORT_LOG_EXPORT_SUCCESS (LogLevel.OK, R.string.msg_export_log_success),
+
+        // mim parsing
+        MSG_MIME_PARSING(LogLevel.START,R.string.msg_mime_parsing_start),
+        MSG_MIME_PARSING_ERROR(LogLevel.ERROR,R.string.msg_mime_parsing_error),
+        MSG_MIME_PARSING_SUCCESS(LogLevel.OK,R.string.msg_mime_parsing_success),
         ;
 
         public final int mMsgId;
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainService.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainService.java
index dca2a08c2..ce4381140 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainService.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainService.java
@@ -36,6 +36,7 @@ import org.sufficientlysecure.keychain.operations.EditKeyOperation;
 import org.sufficientlysecure.keychain.operations.ExportOperation;
 import org.sufficientlysecure.keychain.operations.ImportOperation;
 import org.sufficientlysecure.keychain.operations.KeybaseVerificationOperation;
+import org.sufficientlysecure.keychain.operations.MimeParsingOperation;
 import org.sufficientlysecure.keychain.operations.PromoteKeyOperation;
 import org.sufficientlysecure.keychain.operations.RevokeOperation;
 import org.sufficientlysecure.keychain.operations.SignEncryptOperation;
@@ -137,6 +138,9 @@ public class KeychainService extends Service implements Progressable {
                 } else if (inputParcel instanceof KeybaseVerificationParcel) {
                     op = new KeybaseVerificationOperation(outerThis, new ProviderHelper(outerThis),
                             outerThis);
+                } else if (inputParcel instanceof MimeParsingParcel) {
+                    op = new MimeParsingOperation(outerThis, new ProviderHelper(outerThis),
+                            outerThis);
                 } else {
                     throw new AssertionError("Unrecognized input parcel in KeychainService!");
                 }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/MimeParsingParcel.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/MimeParsingParcel.java
new file mode 100644
index 000000000..ccc817c21
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/MimeParsingParcel.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2015 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.service;
+
+import android.net.Uri;
+import android.os.Parcel;
+import android.os.Parcelable;
+
+public class MimeParsingParcel implements Parcelable {
+
+    private Uri mInputUri;
+    private Uri mOutputUri;
+
+    public MimeParsingParcel() {
+    }
+
+    public MimeParsingParcel(Uri inputUri, Uri outputUri) {
+        mInputUri = inputUri;
+        mOutputUri = outputUri;
+    }
+
+    MimeParsingParcel(Parcel source) {
+        // we do all of those here, so the PgpSignEncryptInput class doesn't have to be parcelable
+        mInputUri = source.readParcelable(getClass().getClassLoader());
+        mOutputUri = source.readParcelable(getClass().getClassLoader());
+    }
+
+    public Uri getInputUri() {
+        return mInputUri;
+    }
+
+    public Uri getOutputUri() {
+        return mOutputUri;
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeParcelable(mInputUri, 0);
+        dest.writeParcelable(mOutputUri, 0);
+    }
+
+    public static final Creator<MimeParsingParcel> CREATOR = new Creator<MimeParsingParcel>() {
+        public MimeParsingParcel createFromParcel(final Parcel source) {
+            return new MimeParsingParcel(source);
+        }
+
+        public MimeParsingParcel[] newArray(final int size) {
+            return new MimeParsingParcel[size];
+        }
+    };
+
+}
+
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptListFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptListFragment.java
index f57d2d056..640755ef3 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptListFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptListFragment.java
@@ -28,7 +28,6 @@ import android.app.Activity;
 import android.content.ClipDescription;
 import android.content.Context;
 import android.content.Intent;
-import android.content.pm.LabeledIntent;
 import android.content.pm.ResolveInfo;
 import android.graphics.Bitmap;
 import android.graphics.Point;
@@ -38,7 +37,6 @@ import android.net.Uri;
 import android.os.AsyncTask;
 import android.os.Build;
 import android.os.Bundle;
-import android.os.Parcelable;
 import android.support.v7.widget.DefaultItemAnimator;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
@@ -58,14 +56,16 @@ import android.widget.ViewAnimator;
 
 import org.openintents.openpgp.OpenPgpMetadata;
 import org.openintents.openpgp.OpenPgpSignatureResult;
-import org.sufficientlysecure.keychain.BuildConfig;
 import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.operations.results.DecryptVerifyResult;
+import org.sufficientlysecure.keychain.operations.results.MimeParsingResult;
 import org.sufficientlysecure.keychain.pgp.PgpDecryptVerifyInputParcel;
 import org.sufficientlysecure.keychain.provider.KeychainContract.KeyRings;
 import org.sufficientlysecure.keychain.provider.TemporaryStorageProvider;
 // this import NEEDS to be above the ViewModel one, or it won't compile! (as of 06/06/15)
+import org.sufficientlysecure.keychain.service.MimeParsingParcel;
+import org.sufficientlysecure.keychain.ui.base.CryptoOperationHelper;
 import org.sufficientlysecure.keychain.ui.base.QueueingCryptoOperationFragment;
 import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils.StatusHolder;
 import org.sufficientlysecure.keychain.ui.DecryptListFragment.DecryptFilesAdapter.ViewModel;
@@ -432,45 +432,47 @@ public class DecryptListFragment
         // OpenKeychain's internal viewer
         if ("text/plain".equals(metadata.getMimeType())) {
 
-            // this is a significant i/o operation, use an asynctask
-            new AsyncTask<Void,Void,Intent>() {
-
-                @Override
-                protected Intent doInBackground(Void... params) {
-
-                    Activity activity = getActivity();
-                    if (activity == null) {
-                        return null;
-                    }
-
-                    Intent intent = new Intent(Intent.ACTION_VIEW);
-                    intent.setDataAndType(outputUri, "text/plain");
-                    intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
-                    return intent;
-                }
-
-                @Override
-                protected void onPostExecute(Intent intent) {
-                    // for result so we can possibly get a snackbar error from internal viewer
-                    Activity activity = getActivity();
-                    if (intent == null || activity == null) {
-                        return;
-                    }
+            parseMime(outputUri);
 
-                    LabeledIntent internalIntent = new LabeledIntent(
-                            new Intent(intent)
-                                    .setClass(activity, DisplayTextActivity.class)
-                                    .putExtra(DisplayTextActivity.EXTRA_METADATA, result),
-                            BuildConfig.APPLICATION_ID, R.string.view_internal, R.drawable.ic_launcher);
-
-                    Intent chooserIntent = Intent.createChooser(intent, getString(R.string.intent_show));
-                    chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS,
-                            new Parcelable[] { internalIntent });
-
-                    activity.startActivity(chooserIntent);
-                }
-
-            }.execute();
+            // this is a significant i/o operation, use an asynctask
+//            new AsyncTask<Void,Void,Intent>() {
+//
+//                @Override
+//                protected Intent doInBackground(Void... params) {
+//
+//                    Activity activity = getActivity();
+//                    if (activity == null) {
+//                        return null;
+//                    }
+//
+//                    Intent intent = new Intent(Intent.ACTION_VIEW);
+//                    intent.setDataAndType(outputUri, "text/plain");
+//                    intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+//                    return intent;
+//                }
+//
+//                @Override
+//                protected void onPostExecute(Intent intent) {
+//                    // for result so we can possibly get a snackbar error from internal viewer
+//                    Activity activity = getActivity();
+//                    if (intent == null || activity == null) {
+//                        return;
+//                    }
+//
+//                    LabeledIntent internalIntent = new LabeledIntent(
+//                            new Intent(intent)
+//                                    .setClass(activity, DisplayTextActivity.class)
+//                                    .putExtra(DisplayTextActivity.EXTRA_METADATA, result),
+//                            BuildConfig.APPLICATION_ID, R.string.view_internal, R.drawable.ic_launcher);
+//
+//                    Intent chooserIntent = Intent.createChooser(intent, getString(R.string.intent_show));
+//                    chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS,
+//                            new Parcelable[] { internalIntent });
+//
+//                    activity.startActivity(chooserIntent);
+//                }
+//
+//            }.execute();
 
         } else {
             Intent intent = new Intent(Intent.ACTION_VIEW);
@@ -484,6 +486,52 @@ public class DecryptListFragment
 
     }
 
+    private void parseMime(final Uri inputUri) {
+
+        CryptoOperationHelper.Callback<MimeParsingParcel, MimeParsingResult> callback
+                = new CryptoOperationHelper.Callback<MimeParsingParcel, MimeParsingResult>() {
+
+            @Override
+            public MimeParsingParcel createOperationInput() {
+                return new MimeParsingParcel(inputUri, null);
+            }
+
+            @Override
+            public void onCryptoOperationSuccess(MimeParsingResult result) {
+                handleResult(result);
+            }
+
+            @Override
+            public void onCryptoOperationCancelled() {
+
+            }
+
+            @Override
+            public void onCryptoOperationError(MimeParsingResult result) {
+                handleResult(result);
+            }
+
+            public void handleResult(MimeParsingResult result) {
+                // TODO: merge with other log
+//                saveKeyResult.getLog().add(result, 0);
+
+                mOutputUris = new HashMap<>(result.getTemporaryUris().size());
+                for (Uri tempUri : result.getTemporaryUris()) {
+                    // TODO: use same inputUri for all?
+                    mOutputUris.put(inputUri, tempUri);
+                }
+            }
+
+            @Override
+            public boolean onCryptoSetProgress(String msg, int progress, int max) {
+                return false;
+            }
+        };
+
+        CryptoOperationHelper mimeParsingHelper = new CryptoOperationHelper<>(3, this, callback, R.string.progress_uploading);
+        mimeParsingHelper.cryptoOperation();
+    }
+
     @Override
     public PgpDecryptVerifyInputParcel createOperationInput() {
 
diff --git a/OpenKeychain/src/main/res/values/strings.xml b/OpenKeychain/src/main/res/values/strings.xml
index 72406aaab..6aa968756 100644
--- a/OpenKeychain/src/main/res/values/strings.xml
+++ b/OpenKeychain/src/main/res/values/strings.xml
@@ -1341,6 +1341,11 @@
     <string name="msg_export_log_error_writing">"I/O error writing to file!"</string>
     <string name="msg_export_log_success">"Log exported successfully!"</string>
 
+    <!-- Messages for Mime parsing operation -->
+    <string name="msg_mime_parsing_start">"Parsing the MIME structure"</string>
+    <string name="msg_mime_parsing_error">"MIME parsing failed"</string>
+    <string name="msg_mime_parsing_success">"MIME parsing successfully!"</string>
+
     <!-- PassphraseCache -->
     <string name="passp_cache_notif_click_to_clear">"Touch to clear passwords."</string>
     <plurals name="passp_cache_notif_n_keys">