User can now specify text/hexdump visualization

app/src/main/java/com/emanuelef/remote_capture/Utils.java

@@ -1125,4 +1125,8 @@ public class Utils {
         icon.setColorFilter(ContextCompat.getColor(context, color));
         icon.setImageDrawable(ContextCompat.getDrawable(context, resid));
     }
+
+    public static boolean isPrintable(byte c) {
+        return ((c >= 32) && (c <= 126)) || (c == '\r') || (c == '\n') || (c == '\t');
+    }
 }

app/src/main/java/com/emanuelef/remote_capture/adapters/PayloadAdapter.java

@@ -19,6 +19,7 @@
 
 package com.emanuelef.remote_capture.adapters;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
 import android.util.Log;
 import android.view.LayoutInflater;
@@ -63,6 +64,7 @@ public class PayloadAdapter extends RecyclerView.Adapter<PayloadAdapter.PayloadV
     private final ArrayList<AdapterChunk> mChunks = new ArrayList<>();
     private final HTTPReassembly mHttpReq;
     private final HTTPReassembly mHttpRes;
+    private boolean mShowAsPrintable;
 
     public PayloadAdapter(Context context, ConnectionDescriptor conn, ChunkType mode) {
         mLayoutInflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
@@ -111,15 +113,13 @@ public class PayloadAdapter extends RecyclerView.Adapter<PayloadAdapter.PayloadV
         private void makeText() {
             int dump_len = mIsExpanded ? mChunk.payload.length : Math.min(mChunk.payload.length, COLLAPSE_CHUNK_SIZE);
 
-            if(mMode == ChunkType.RAW)
+            if(!mShowAsPrintable)
                 mTheText = Utils.hexdump(mChunk.payload, 0, dump_len);
             else
                 mTheText = new String(mChunk.payload, 0, dump_len, StandardCharsets.UTF_8);
         }
 
         void expand() {
-            assert(!mIsExpanded);
-
             mIsExpanded = true;
             makeText();
 
@@ -129,8 +129,6 @@ public class PayloadAdapter extends RecyclerView.Adapter<PayloadAdapter.PayloadV
 
         // collapses the item and returns the old number of pages
         void collapse() {
-            assert(mIsExpanded);
-
             mIsExpanded = false;
             mTheText = null;
 
@@ -307,6 +305,19 @@ public class PayloadAdapter extends RecyclerView.Adapter<PayloadAdapter.PayloadV
         return mChunks.get(i).getPage(pageIdx);
     }
 
+    @SuppressLint("NotifyDataSetChanged")
+    public void setDisplayAsPrintableText(boolean asText) {
+        if(mShowAsPrintable != asText) {
+            mShowAsPrintable = asText;
+
+            // Chunk pagination depends on the displayed data length, collapsing everything is simpler
+            // than handling individual changes
+            for(AdapterChunk chunk: mChunks)
+                chunk.collapse(); // resets the chunk text
+            notifyDataSetChanged();
+        }
+    }
+
     private int getAdapterPosition(AdapterChunk chunk) {
         int i;
         int count = 0;

app/src/main/java/com/emanuelef/remote_capture/fragments/ConnectionPayload.java

@@ -22,6 +22,9 @@ package com.emanuelef.remote_capture.fragments;
 import android.content.Context;
 import android.os.Bundle;
 import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.TextView;
@@ -31,6 +34,7 @@ import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
 
 import com.emanuelef.remote_capture.R;
+import com.emanuelef.remote_capture.Utils;
 import com.emanuelef.remote_capture.activities.ConnectionDetailsActivity;
 import com.emanuelef.remote_capture.adapters.PayloadAdapter;
 import com.emanuelef.remote_capture.model.ConnectionDescriptor;
@@ -43,6 +47,9 @@ public class ConnectionPayload extends Fragment implements ConnectionDetailsActi
     private PayloadAdapter mAdapter;
     private TextView mTruncatedWarning;
     private int mCurChunks;
+    private Menu mMenu;
+    private boolean mJustCreated;
+    private boolean mShowAsPrintable;
 
     public static ConnectionPayload newInstance(PayloadChunk.ChunkType mode) {
         ConnectionPayload fragment = new ConnectionPayload();
@@ -70,6 +77,7 @@ public class ConnectionPayload extends Fragment implements ConnectionDetailsActi
     @Override
     public View onCreateView(LayoutInflater inflater,
                              ViewGroup container, Bundle savedInstanceState) {
+        setHasOptionsMenu(true);
         return inflater.inflate(R.layout.connection_payload, container, false);
     }
 
@@ -94,10 +102,83 @@ public class ConnectionPayload extends Fragment implements ConnectionDetailsActi
         mAdapter = new PayloadAdapter(requireContext(), mConn, mode);
         mCurChunks = mConn.getNumPayloadChunks();
         recyclerView.setAdapter(mAdapter);
+        mJustCreated = true;
+    }
+
+    @Override
+    public void onCreateOptionsMenu(@NonNull Menu menu, MenuInflater menuInflater) {
+        menuInflater.inflate(R.menu.connection_payload, menu);
+        mMenu = menu;
+        if((mCurChunks > 0) && mJustCreated) {
+            mShowAsPrintable = guessDisplayAsPrintable();
+            mAdapter.setDisplayAsPrintableText(mShowAsPrintable);
+            mJustCreated = false;
+        }
+        refreshDisplayMode();
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
+        int id = item.getItemId();
+
+        if(id == R.id.printable_text) {
+            mShowAsPrintable = true;
+            mAdapter.setDisplayAsPrintableText(true);
+            refreshDisplayMode();
+            return true;
+        } else if(id == R.id.hexdump) {
+            mShowAsPrintable = false;
+            mAdapter.setDisplayAsPrintableText(false);
+            refreshDisplayMode();
+            return true;
+        }
+
+        return super.onOptionsItemSelected(item);
+    }
+
+    private boolean guessDisplayAsPrintable() {
+        // try to determine the best mode based on the current payload
+        if(mConn.getNumPayloadChunks() == 0)
+            return mConn.l7proto.equals("HTTPS");
+
+        PayloadChunk firstChunk = mConn.getPayloadChunk(0);
+        if(firstChunk.type == PayloadChunk.ChunkType.HTTP)
+            return true;
+
+        // guess based on the actual data
+        int maxLen = Math.min(firstChunk.payload.length, 16);
+        for(int i=0; i<maxLen; i++) {
+            if(!Utils.isPrintable(firstChunk.payload[i]))
+                return false;
+        }
+
+        return true;
+    }
+
+    private void refreshDisplayMode() {
+        if(mMenu == null)
+            return;
+
+        MenuItem printableText = mMenu.findItem(R.id.printable_text);
+        MenuItem hexdump = mMenu.findItem(R.id.hexdump);
+
+        // important: the checked item must first be unchecked
+        if(mShowAsPrintable) {
+            hexdump.setChecked(false);
+            printableText.setChecked(true);
+        } else {
+            printableText.setChecked(false);
+            hexdump.setChecked(true);
+        }
     }
 
     @Override
     public void connectionUpdated() {
+        if(mCurChunks == 0) {
+            mShowAsPrintable = guessDisplayAsPrintable();
+            mAdapter.setDisplayAsPrintableText(mShowAsPrintable);
+        }
+
         if(mConn.getNumPayloadChunks() > mCurChunks) {
             mAdapter.handleChunksAdded(mConn.getNumPayloadChunks());
             mCurChunks = mConn.getNumPayloadChunks();

app/src/main/res/drawable/ic_short_text.xml

@@ -0,0 +1,5 @@
+<vector android:autoMirrored="true" android:height="24dp"
+    android:tint="?attr/colorControlNormal" android:viewportHeight="24"
+    android:viewportWidth="24" android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M4,9h16v2H4V9zM4,13h10v2H4V13z"/>
+</vector>

app/src/main/res/menu/connection_payload.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <item
+        android:title="@string/display_as"
+        android:icon="@drawable/ic_short_text"
+        app:showAsAction="ifRoom">
+        <menu>
+            <group android:id="@+id/display_as_grp" android:checkableBehavior="single">
+                <item
+                    android:id="@+id/printable_text"
+                    android:title="@string/printable_text" />
+                <item
+                    android:id="@+id/hexdump"
+                    android:title="@string/hexdump" />
+            </group>
+        </menu>
+    </item>
+</menu>

app/src/main/res/values/strings.xml

@@ -314,4 +314,7 @@
     <string name="network_traffic">Traffic</string>
     <string name="warn_no_app_data">No application data has been exchanged</string>
     <string name="waiting_application_data">Waiting data</string>
+    <string name="display_as">Display as…</string>
+    <string name="printable_text">Printable text</string>
+    <string name="hexdump">Hexdump</string>
 </resources>