From 7a386a7f2a4d0d0600e1c026486a5f4d04b31803 Mon Sep 17 00:00:00 2001
From: agnostic-apollo <agnosticapollo@gmail.com>
Date: Mon, 15 Nov 2021 07:31:14 +0500
Subject: [PATCH] Fixed: Fix ArrayIndexOutOfBoundsException when setting zero
 width terminal character

java.lang.ArrayIndexOutOfBoundsException: length=64; index=-1
at com.termux.terminal.TerminalRow.setChar(TerminalRow.java:127)
at com.termux.terminal.TerminalBuffer.setChar(TerminalBuffer.java:413)
at com.termux.terminal.TerminalEmulator.emitCodePoint(TerminalEmulator.java:2329)
at com.termux.terminal.TerminalEmulator.processCodePoint(TerminalEmulator.java:617)
at com.termux.terminal.TerminalEmulator.processByte(TerminalEmulator.java:513)
at com.termux.terminal.TerminalEmulator.append(TerminalEmulator.java:480)
at com.termux.terminal.TerminalSession$MainThreadHandler.handleMessage(TerminalSession.java:339)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:219)
at android.app.ActivityThread.main(ActivityThread.java:8349)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1055)
---
 .../main/java/com/termux/terminal/TerminalBuffer.java    | 4 ++--
 .../main/java/com/termux/terminal/TerminalEmulator.java  | 9 ++++++++-
 .../src/main/java/com/termux/terminal/TerminalRow.java   | 3 +++
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/terminal-emulator/src/main/java/com/termux/terminal/TerminalBuffer.java b/terminal-emulator/src/main/java/com/termux/terminal/TerminalBuffer.java
index 4a74ee6f..df57bd36 100644
--- a/terminal-emulator/src/main/java/com/termux/terminal/TerminalBuffer.java
+++ b/terminal-emulator/src/main/java/com/termux/terminal/TerminalBuffer.java
@@ -449,8 +449,8 @@ public final class TerminalBuffer {
     }
 
     public void setChar(int column, int row, int codePoint, long style) {
-        if (row >= mScreenRows || column >= mColumns)
-            throw new IllegalArgumentException("row=" + row + ", column=" + column + ", mScreenRows=" + mScreenRows + ", mColumns=" + mColumns);
+        if (row  < 0 || row >= mScreenRows || column < 0 || column >= mColumns)
+            throw new IllegalArgumentException("TerminalBuffer.setChar(): row=" + row + ", column=" + column + ", mScreenRows=" + mScreenRows + ", mColumns=" + mColumns);
         row = externalToInternalRow(row);
         allocateFullLineIfNecessary(row).setChar(column, codePoint, style);
     }
diff --git a/terminal-emulator/src/main/java/com/termux/terminal/TerminalEmulator.java b/terminal-emulator/src/main/java/com/termux/terminal/TerminalEmulator.java
index 8efb949b..975c1a5a 100644
--- a/terminal-emulator/src/main/java/com/termux/terminal/TerminalEmulator.java
+++ b/terminal-emulator/src/main/java/com/termux/terminal/TerminalEmulator.java
@@ -2332,7 +2332,14 @@ public final class TerminalEmulator {
         }
 
         int offsetDueToCombiningChar = ((displayWidth <= 0 && mCursorCol > 0 && !mAboutToAutoWrap) ? 1 : 0);
-        mScreen.setChar(mCursorCol - offsetDueToCombiningChar, mCursorRow, codePoint, getStyle());
+        int column = mCursorCol - offsetDueToCombiningChar;
+
+        // Fix TerminalRow.setChar() ArrayIndexOutOfBoundsException index=-1 exception reported
+        // The offsetDueToCombiningChar would never be 1 if mCursorCol was 0 to get column/index=-1,
+        // so was mCursorCol changed after the offsetDueToCombiningChar conditional by another thread?
+        // TODO: Check if there are thread synchronization issues with mCursorCol and mCursorRow, possibly causing others bugs too.
+        if (column < 0) column = 0;
+        mScreen.setChar(column, mCursorRow, codePoint, getStyle());
 
         if (autoWrap && displayWidth > 0)
             mAboutToAutoWrap = (mCursorCol == mRightMargin - displayWidth);
diff --git a/terminal-emulator/src/main/java/com/termux/terminal/TerminalRow.java b/terminal-emulator/src/main/java/com/termux/terminal/TerminalRow.java
index cefdd4f7..cbeaf522 100644
--- a/terminal-emulator/src/main/java/com/termux/terminal/TerminalRow.java
+++ b/terminal-emulator/src/main/java/com/termux/terminal/TerminalRow.java
@@ -124,6 +124,9 @@ public final class TerminalRow {
 
     // https://github.com/steven676/Android-Terminal-Emulator/commit/9a47042620bec87617f0b4f5d50568535668fe26
     public void setChar(int columnToSet, int codePoint, long style) {
+        if (columnToSet  < 0 || columnToSet >= mStyle.length)
+            throw new IllegalArgumentException("TerminalRow.setChar(): columnToSet=" + columnToSet + ", codePoint=" + codePoint + ", style=" + style);
+
         mStyle[columnToSet] = style;
 
         final int newCodePointDisplayWidth = WcWidth.width(codePoint);