Allow users to adjust terminal transcript rows with termux.properties

This `terminal-transcript-rows` key can be used to adjust the terminal transcript rows. The user can set an integer value between `100` and `50000`. The default value is still `2000`. So adding an entry like `terminal-transcript-rows=10000` to `termux.properties` file will allow users to scroll back ~10000 lines of command output. After updating the value, termux must be restarted. You can also run `termux-reload-settings` command so that termux loads the updated value, but only new sessions will use the updated value, existing sessions will not be affected.

You can test this with the following, where `70` is number of `x` characters per line and `10001` is the number of lines to print.
`x="$(printf 'x%.0s' {1..70})"; for i in {1..10001}; do echo "$i:$x"; done`

Be advised that using large values may have a performance impact depending on your device capabilities, so use at your own risk.

Closes #2071

Author: agnostic-apollo

app/src/main/java/com/termux/app/TermuxActivity.java

@@ -846,6 +846,9 @@ private void reloadActivityStyling() {
         if (mTermuxTerminalViewClient != null)
             mTermuxTerminalViewClient.onReload();
 
+        if (mTermuxService != null)
+            mTermuxService.setTerminalTranscriptRows();
+
         // To change the activity and drawer theme, activity needs to be recreated.
         // But this will destroy the activity, and will call the onCreate() again.
         // We need to investigate if enabling this is wise, since all stored variables and

app/src/main/java/com/termux/app/TermuxService.java

@@ -20,6 +20,7 @@
 import android.widget.ArrayAdapter;
 
 import com.termux.R;
+import com.termux.app.settings.properties.TermuxAppSharedProperties;
 import com.termux.app.terminal.TermuxTerminalSessionClient;
 import com.termux.app.utils.PluginUtils;
 import com.termux.shared.termux.TermuxConstants;
@@ -106,6 +107,8 @@ class LocalBinder extends Binder {
     /** If the user has executed the {@link TERMUX_SERVICE#ACTION_STOP_SERVICE} intent. */
     boolean mWantsToStop = false;
 
+    public Integer mTerminalTranscriptRows;
+
     private static final String LOG_TAG = "TermuxService";
 
     @Override
@@ -503,6 +506,7 @@ public synchronized TermuxSession createTermuxSession(ExecutionCommand execution
         // If the execution command was started for a plugin, only then will the stdout be set
         // Otherwise if command was manually started by the user like by adding a new terminal session,
         // then no need to set stdout
+        executionCommand.terminalTranscriptRows = getTerminalTranscriptRows();
         TermuxSession newTermuxSession = TermuxSession.execute(this, executionCommand, getTermuxTerminalSessionClient(), this, sessionName, executionCommand.isPluginExecutionCommand);
         if (newTermuxSession == null) {
             Logger.logError(LOG_TAG, "Failed to execute new TermuxSession command for:\n" + executionCommand.getCommandIdAndLabelLogString());
@@ -560,6 +564,19 @@ public void onTermuxSessionExited(final TermuxSession termuxSession) {
         updateNotification();
     }
 
+    /** Get the terminal transcript rows to be used for new {@link TermuxSession}. */
+    public Integer getTerminalTranscriptRows() {
+        if (mTerminalTranscriptRows == null)
+            setTerminalTranscriptRows();
+        return mTerminalTranscriptRows;
+    }
+
+    public void setTerminalTranscriptRows() {
+        // TermuxService only uses this termux property currently, so no need to load them all into
+        // an internal values map like TermuxActivity does
+        mTerminalTranscriptRows = TermuxAppSharedProperties.getTerminalTranscriptRows(this);
+    }
+
 
 
 

app/src/main/java/com/termux/app/settings/properties/TermuxAppSharedProperties.java

@@ -5,7 +5,6 @@
 import com.termux.app.terminal.io.KeyboardShortcut;
 import com.termux.app.terminal.io.extrakeys.ExtraKeysInfo;
 import com.termux.shared.logger.Logger;
-import com.termux.shared.settings.properties.SharedPropertiesParser;
 import com.termux.shared.settings.properties.TermuxPropertyConstants;
 import com.termux.shared.settings.properties.TermuxSharedProperties;
 
@@ -17,7 +16,7 @@
 
 import javax.annotation.Nonnull;
 
-public class TermuxAppSharedProperties extends TermuxSharedProperties implements SharedPropertiesParser {
+public class TermuxAppSharedProperties extends TermuxSharedProperties {
 
     private ExtraKeysInfo mExtraKeysInfo;
     private List<KeyboardShortcut> mSessionShortcuts = new ArrayList<>();
@@ -96,4 +95,13 @@ public ExtraKeysInfo getExtraKeysInfo() {
         return mExtraKeysInfo;
     }
 
+
+
+    /**
+     * Load the {@link TermuxPropertyConstants#KEY_TERMINAL_TRANSCRIPT_ROWS} value from termux properties file on disk.
+     */
+    public static int getTerminalTranscriptRows(Context context) {
+        return  (int) TermuxSharedProperties.getInternalPropertyValue(context, TermuxPropertyConstants.KEY_TERMINAL_TRANSCRIPT_ROWS);
+    }
+
 }

terminal-emulator/src/main/java/com/termux/terminal/TerminalEmulator.java

@@ -137,6 +137,11 @@ public final class TerminalEmulator {
     /** The number of character rows and columns in the terminal screen. */
     public int mRows, mColumns;
 
+    /** The number of terminal transcript rows that can be scrolled back to. */
+    public static final int TERMINAL_TRANSCRIPT_ROWS_MIN = 100;
+    public static final int TERMINAL_TRANSCRIPT_ROWS_MAX = 50000;
+    public static final int DEFAULT_TERMINAL_TRANSCRIPT_ROWS = 2000;
+
     /** The normal screen buffer. Stores the characters that appear on the screen of the emulated terminal. */
     private final TerminalBuffer mMainBuffer;
     /**
@@ -294,9 +299,9 @@ static int mapDecSetBitToInternalBit(int decsetBit) {
         }
     }
 
-    public TerminalEmulator(TerminalOutput session, int columns, int rows, int transcriptRows, TerminalSessionClient client) {
+    public TerminalEmulator(TerminalOutput session, int columns, int rows, Integer transcriptRows, TerminalSessionClient client) {
         mSession = session;
-        mScreen = mMainBuffer = new TerminalBuffer(columns, transcriptRows, rows);
+        mScreen = mMainBuffer = new TerminalBuffer(columns, getTerminalTranscriptRows(transcriptRows), rows);
         mAltBuffer = new TerminalBuffer(columns, rows, rows);
         mClient = client;
         mRows = rows;
@@ -317,6 +322,13 @@ public boolean isAlternateBufferActive() {
         return mScreen == mAltBuffer;
     }
 
+    private int getTerminalTranscriptRows(Integer transcriptRows) {
+        if (transcriptRows == null || transcriptRows < TERMINAL_TRANSCRIPT_ROWS_MIN || transcriptRows > TERMINAL_TRANSCRIPT_ROWS_MAX)
+            return DEFAULT_TERMINAL_TRANSCRIPT_ROWS;
+        else
+            return transcriptRows;
+    }
+
     /**
      * @param mouseButton one of the MOUSE_* constants of this class.
      */

terminal-emulator/src/main/java/com/termux/terminal/TerminalSession.java

@@ -74,14 +74,17 @@ public final class TerminalSession extends TerminalOutput {
     private final String mCwd;
     private final String[] mArgs;
     private final String[] mEnv;
+    private final Integer mTranscriptRows;
+
 
     private static final String LOG_TAG = "TerminalSession";
 
-    public TerminalSession(String shellPath, String cwd, String[] args, String[] env, TerminalSessionClient client) {
+    public TerminalSession(String shellPath, String cwd, String[] args, String[] env, Integer transcriptRows, TerminalSessionClient client) {
         this.mShellPath = shellPath;
         this.mCwd = cwd;
         this.mArgs = args;
         this.mEnv = env;
+        this.mTranscriptRows = transcriptRows;
         this.mClient = client;
     }
 
@@ -118,7 +121,7 @@ public String getTitle() {
      * @param rows    The number of rows in the terminal window.
      */
     public void initializeEmulator(int columns, int rows) {
-        mEmulator = new TerminalEmulator(this, columns, rows, /* transcript= */2000, mClient);
+        mEmulator = new TerminalEmulator(this, columns, rows, mTranscriptRows, mClient);
 
         int[] processId = new int[1];
         mTerminalFileDescriptor = JNI.createSubprocess(mShellPath, mCwd, mArgs, mEnv, processId, rows, columns);

termux-shared/src/main/java/com/termux/shared/models/ExecutionCommand.java

@@ -81,6 +81,10 @@ public int getValue() {
     public String workingDirectory;
 
 
+    /** The terminal transcript rows for the {@link ExecutionCommand}. */
+    public Integer terminalTranscriptRows;
+
+
     /** If the {@link ExecutionCommand} is a background or a foreground terminal session command. */
     public boolean inBackground;
     /** If the {@link ExecutionCommand} is meant to start a failsafe terminal session. */

termux-shared/src/main/java/com/termux/shared/settings/properties/TermuxPropertyConstants.java

@@ -3,6 +3,7 @@
 import com.google.common.collect.ImmutableBiMap;
 import com.termux.shared.termux.TermuxConstants;
 import com.termux.shared.logger.Logger;
+import com.termux.terminal.TerminalEmulator;
 import com.termux.view.TerminalView;
 
 import java.io.File;
@@ -11,7 +12,7 @@
 import java.util.Set;
 
 /*
- * Version: v0.10.0
+ * Version: v0.11.0
  *
  * Changelog
  *
@@ -49,6 +50,9 @@
  * - 0.10.0 (2021-05-15)
  *      - Add `MAP_BACK_KEY_BEHAVIOUR`, `MAP_SOFT_KEYBOARD_TOGGLE_BEHAVIOUR`, `MAP_VOLUME_KEYS_BEHAVIOUR`.
  *
+ * - 0.11.0 (2021-06-10)
+ *      - Add `*KEY_TERMINAL_TRANSCRIPT_ROWS*`.
+ *
  */
 
 /**
@@ -131,6 +135,14 @@ public final class TermuxPropertyConstants {
 
 
 
+    /** Defines the key for the terminal transcript rows */
+    public static final String KEY_TERMINAL_TRANSCRIPT_ROWS =  "terminal-transcript-rows"; // Default: "terminal-transcript-rows"
+    public static final int IVALUE_TERMINAL_TRANSCRIPT_ROWS_MIN = TerminalEmulator.TERMINAL_TRANSCRIPT_ROWS_MIN;
+    public static final int IVALUE_TERMINAL_TRANSCRIPT_ROWS_MAX = TerminalEmulator.TERMINAL_TRANSCRIPT_ROWS_MAX;
+    public static final int DEFAULT_IVALUE_TERMINAL_TRANSCRIPT_ROWS = TerminalEmulator.DEFAULT_TERMINAL_TRANSCRIPT_ROWS;
+
+
+
 
 
     /* float */
@@ -259,6 +271,7 @@ public final class TermuxPropertyConstants {
         /* int */
         KEY_BELL_BEHAVIOUR,
         KEY_TERMINAL_CURSOR_BLINK_RATE,
+        KEY_TERMINAL_TRANSCRIPT_ROWS,
 
         /* float */
         KEY_TERMINAL_TOOLBAR_HEIGHT_SCALE_FACTOR,

termux-shared/src/main/java/com/termux/shared/settings/properties/TermuxSharedProperties.java

@@ -13,7 +13,7 @@
 
 import javax.annotation.Nonnull;
 
-public class TermuxSharedProperties implements SharedPropertiesParser {
+public class TermuxSharedProperties {
 
     protected final Context mContext;
     protected final SharedProperties mSharedProperties;
@@ -24,7 +24,7 @@ public class TermuxSharedProperties implements SharedPropertiesParser {
     public TermuxSharedProperties(@Nonnull Context context) {
         mContext = context;
         mPropertiesFile = TermuxPropertyConstants.getTermuxPropertiesFile();
-        mSharedProperties = new SharedProperties(context, mPropertiesFile, TermuxPropertyConstants.TERMUX_PROPERTIES_LIST, this);
+        mSharedProperties = new SharedProperties(context, mPropertiesFile, TermuxPropertyConstants.TERMUX_PROPERTIES_LIST, new SharedPropertiesParserClient());
         loadTermuxPropertiesFromDisk();
     }
 
@@ -146,24 +146,47 @@ public Object getInternalPropertyValue(String key, boolean cached) {
                 // {@link #loadTermuxPropertiesFromDisk()} call
                 // A null value can still be returned by
                 // {@link #getInternalPropertyValueFromValue(Context,String,String)} for some keys
-                value = getInternalPropertyValueFromValue(mContext, key, null);
+                value = getInternalTermuxPropertyValueFromValue(mContext, key, null);
                 Logger.logWarn(LOG_TAG, "The value for \"" + key + "\" not found in SharedProperties cache, force returning default value: `" + value +  "`");
                 return value;
             }
         } else {
             // We get the property value directly from file and return its internal value
-            return getInternalPropertyValueFromValue(mContext, key, mSharedProperties.getProperty(key, false));
+            return getInternalTermuxPropertyValueFromValue(mContext, key, mSharedProperties.getProperty(key, false));
         }
     }
 
+
+
+
+
     /**
-     * Override the
-     * {@link SharedPropertiesParser#getInternalPropertyValueFromValue(Context,String,String)}
-     * interface function.
+     * Get the internal {@link Object} value for the key passed from the file returned by
+     * {@link TermuxPropertyConstants#getTermuxPropertiesFile()}. The {@link Properties} object is
+     * read directly from the file and internal value is returned for the property value against the key.
+     *
+     * @param context The context for operations.
+     * @param key The key for which the internal object is required.
+     * @return Returns the {@link Object} object. This will be {@code null} if key is not found or
+     * the object stored against the key is {@code null}.
      */
-    @Override
-    public Object getInternalPropertyValueFromValue(Context context, String key, String value) {
-        return getInternalTermuxPropertyValueFromValue(context, key, value);
+    public static Object getInternalPropertyValue(Context context, String key) {
+        return SharedProperties.getInternalProperty(context, TermuxPropertyConstants.getTermuxPropertiesFile(), key, new SharedPropertiesParserClient());
+    }
+
+    /**
+     * The class that implements the {@link SharedPropertiesParser} interface.
+     */
+    public static class SharedPropertiesParserClient implements SharedPropertiesParser {
+        /**
+         * Override the
+         * {@link SharedPropertiesParser#getInternalPropertyValueFromValue(Context,String,String)}
+         * interface function.
+         */
+        @Override
+        public Object getInternalPropertyValueFromValue(Context context, String key, String value) {
+            return getInternalTermuxPropertyValueFromValue(context, key, value);
+        }
     }
 
     /**
@@ -194,6 +217,8 @@ public static Object getInternalTermuxPropertyValueFromValue(Context context, St
                 return (int) getBellBehaviourInternalPropertyValueFromValue(value);
             case TermuxPropertyConstants.KEY_TERMINAL_CURSOR_BLINK_RATE:
                 return (int) getTerminalCursorBlinkRateInternalPropertyValueFromValue(value);
+            case TermuxPropertyConstants.KEY_TERMINAL_TRANSCRIPT_ROWS:
+                return (int) getTerminalTranscriptRowsInternalPropertyValueFromValue(value);
 
             /* float */
             case TermuxPropertyConstants.KEY_TERMINAL_TOOLBAR_HEIGHT_SCALE_FACTOR:
@@ -263,9 +288,9 @@ public static int getBellBehaviourInternalPropertyValueFromValue(String value) {
 
     /**
      * Returns the int for the value if its not null and is between
-     * {@code TermuxPropertyConstants#IVALUE_TERMINAL_TOOLBAR_HEIGHT_SCALE_FACTOR_MIN} and
-     * {@code TermuxPropertyConstants#IVALUE_TERMINAL_TOOLBAR_HEIGHT_SCALE_FACTOR_MAX},
-     * otherwise returns {@code TermuxPropertyConstants#DEFAULT_IVALUE_TERMINAL_TOOLBAR_HEIGHT_SCALE_FACTOR}.
+     * {@code TermuxPropertyConstants#IVALUE_TERMINAL_CURSOR_BLINK_RATE_MIN} and
+     * {@code TermuxPropertyConstants#IVALUE_TERMINAL_CURSOR_BLINK_RATE_MAX},
+     * otherwise returns {@code TermuxPropertyConstants#DEFAULT_IVALUE_TERMINAL_CURSOR_BLINK_RATE}.
      *
      * @param value The {@link String} value to convert.
      * @return Returns the internal value for value.
@@ -279,6 +304,24 @@ public static float getTerminalCursorBlinkRateInternalPropertyValueFromValue(Str
                     true, true, LOG_TAG);
     }
 
+    /**
+     * Returns the int for the value if its not null and is between
+     * {@code TermuxPropertyConstants#IVALUE_TERMINAL_TRANSCRIPT_ROWS_MIN} and
+     * {@code TermuxPropertyConstants#IVALUE_TERMINAL_TRANSCRIPT_ROWS_MAX},
+     * otherwise returns {@code TermuxPropertyConstants#DEFAULT_IVALUE_TERMINAL_TRANSCRIPT_ROWS}.
+     *
+     * @param value The {@link String} value to convert.
+     * @return Returns the internal value for value.
+     */
+    public static float getTerminalTranscriptRowsInternalPropertyValueFromValue(String value) {
+        return SharedProperties.getDefaultIfNotInRange(TermuxPropertyConstants.KEY_TERMINAL_TRANSCRIPT_ROWS,
+            DataUtils.getIntFromString(value, TermuxPropertyConstants.DEFAULT_IVALUE_TERMINAL_TRANSCRIPT_ROWS),
+            TermuxPropertyConstants.DEFAULT_IVALUE_TERMINAL_TRANSCRIPT_ROWS,
+            TermuxPropertyConstants.IVALUE_TERMINAL_TRANSCRIPT_ROWS_MIN,
+            TermuxPropertyConstants.IVALUE_TERMINAL_TRANSCRIPT_ROWS_MAX,
+            true, true, LOG_TAG);
+    }
+
     /**
      * Returns the int for the value if its not null and is between
      * {@code TermuxPropertyConstants#IVALUE_TERMINAL_TOOLBAR_HEIGHT_SCALE_FACTOR_MIN} and
@@ -435,6 +478,10 @@ public int getTerminalCursorBlinkRate() {
         return (int) getInternalPropertyValue(TermuxPropertyConstants.KEY_TERMINAL_CURSOR_BLINK_RATE, true);
     }
 
+    public int getTerminalTranscriptRows() {
+        return (int) getInternalPropertyValue(TermuxPropertyConstants.KEY_TERMINAL_TRANSCRIPT_ROWS, true);
+    }
+
     public float getTerminalToolbarHeightScaleFactor() {
         return (float) getInternalPropertyValue(TermuxPropertyConstants.KEY_TERMINAL_TOOLBAR_HEIGHT_SCALE_FACTOR, true);
     }

termux-shared/src/main/java/com/termux/shared/shell/TermuxSession.java

@@ -109,7 +109,7 @@ public static TermuxSession execute(@NonNull final Context context, @NonNull Exe
         Logger.logDebug(LOG_TAG, executionCommand.toString());
 
         Logger.logDebug(LOG_TAG, "Running \"" + executionCommand.getCommandIdAndLabelLogString() + "\" TermuxSession");
-        TerminalSession terminalSession = new TerminalSession(executionCommand.executable, executionCommand.workingDirectory, executionCommand.arguments, environment, terminalSessionClient);
+        TerminalSession terminalSession = new TerminalSession(executionCommand.executable, executionCommand.workingDirectory, executionCommand.arguments, environment, executionCommand.terminalTranscriptRows, terminalSessionClient);
 
         if (sessionName != null) {
             terminalSession.mSessionName = sessionName;