WinSCP Compare Files — Wine/Linux Meld alternative to WinMerge

winscp-meld-compare.sh

#!/bin/bash
#
# WinSCP Compare Files — Wine/Linux Fix
# ======================================
#
# Fix for WinSCP's broken "Compare Files" feature when running under Wine on Linux.
#
# PROBLEM:
#   WinSCP's built-in Compare Files extension is PowerShell-based. On native
#   Windows this works perfectly — WinMerge opens with the temp file vs local
#   file, edits are detected and uploaded. Under Wine, it fails because
#   PowerShell is not available. The extension either does nothing or falls
#   back to prompting for a new session.
#
# WHY IS THIS SO COMPLICATED:
#   Simply replacing PowerShell with a batch script isn't enough. Wine's
#   virtual filesystem creates a subtle problem: when WinSCP downloads
#   a remote file to a temp location, the file exists inside Wine's VFS
#   but is NOT visible to native Linux processes. A native diff tool
#   launched via Wine's `start /unix` simply cannot see the temp file.
#   The workaround: a batch script running inside Wine (where the file IS
#   visible) copies it to /tmp on the real Linux filesystem, then launches
#   the native diff tool. When the tool closes, modifications are copied
#   back to Wine's temp location so WinSCP detects the change and uploads.
#
# WHAT THIS INSTALLER DOES:
#   - Detects WinSCP installation path and Wine prefix automatically
#   - Checks for Meld, offers to install it (pacman/apt/dnf/zypper/flatpak)
#   - Creates a .WinSCPextension.bat that replaces the broken built-in
#   - Creates a Wine batch wrapper that bridges Wine VFS → Linux filesystem
#   - Creates a native Linux helper script for launching Meld
#   - Updates WinSCP.ini (disables broken extension, adds Meld custom command)
#   - Backs up WinSCP.ini before any changes
#
# AFTER INSTALLATION:
#   - Compare Files:  Commands menu > Compare Files  (Shift+Ctrl+Alt+C)
#   - Meld command:   Commands menu > Custom Commands > Meld
#   - WinSCP blocks while Meld is open (same as native Windows behavior)
#   - Edits to the remote file in Meld are detected and uploaded by WinSCP
#
# REQUIREMENTS:
#   - WinSCP running under Wine (portable mode with WinSCP.ini)
#   - Meld (installed automatically if missing)
#   - Bash 4+ (for associative arrays)
#
# TESTED WITH:
#   - WinSCP 6.x, Wine 9.x/10.x
#   - Arch Linux, Ubuntu, Fedora
#
# KEYWORDS (for searchability):
#   WinSCP Wine Linux, WinSCP compare files not working Wine,
#   WinSCP extension Wine fix, WinSCP PowerShell Wine replacement,
#   WinSCP Meld Linux, WinSCP diff tool Wine, WinSCP compare Wine broken,
#   WinSCP new session error compare, WinSCP WinSCPnet.dll Wine
#
# Usage: ./winscp-meld-compare.sh [--winscp-path /path/to/WinSCP]
#                                    [--wine-prefix ~/.wine]
#                                    [--uninstall]
#
# License: MIT
#

set -euo pipefail

# --- Colors ---
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
BOLD='\033[1m'
NC='\033[0m'

info()  { echo -e "${BLUE}::${NC} $*"; }
ok()    { echo -e "${GREEN}::${NC} $*"; }
warn()  { echo -e "${YELLOW}:: WARNING:${NC} $*"; }
err()   { echo -e "${RED}:: ERROR:${NC} $*" >&2; }
die()   { err "$*"; exit 1; }

# --- Defaults ---
WINSCP_PATH=""
WINE_PREFIX="${WINEPREFIX:-$HOME/.wine}"
UNINSTALL=0

# --- Parse args ---
while [[ $# -gt 0 ]]; do
    case "$1" in
        --winscp-path) WINSCP_PATH="$2"; shift 2 ;;
        --wine-prefix) WINE_PREFIX="$2"; shift 2 ;;
        --uninstall)   UNINSTALL=1; shift ;;
        --help|-h)
            echo "Usage: $0 [OPTIONS]"
            echo ""
            echo "Options:"
            echo "  --winscp-path PATH   Path to WinSCP installation directory"
            echo "  --wine-prefix PATH   Wine prefix (default: \$WINEPREFIX or ~/.wine)"
            echo "  --uninstall          Remove the Compare Files extension"
            echo "  --help               Show this help"
            exit 0
            ;;
        *) die "Unknown option: $1" ;;
    esac
done

# --- Detect WinSCP ---
find_winscp() {
    local candidates=(
        "/opt/WinSCP"
        "$HOME/WinSCP"
        "$WINE_PREFIX/drive_c/Program Files/WinSCP"
        "$WINE_PREFIX/drive_c/Program Files (x86)/WinSCP"
    )

    for dir in "${candidates[@]}"; do
        if [[ -f "$dir/WinSCP.exe" ]]; then
            echo "$dir"
            return 0
        fi
    done

    # Search Wine prefix
    local found
    found=$(find "$WINE_PREFIX/drive_c" -maxdepth 3 -name "WinSCP.exe" -type f 2>/dev/null | head -1)
    if [[ -n "$found" ]]; then
        dirname "$found"
        return 0
    fi

    # Search common system paths
    found=$(find /opt /usr/local -maxdepth 2 -name "WinSCP.exe" -type f 2>/dev/null | head -1)
    if [[ -n "$found" ]]; then
        dirname "$found"
        return 0
    fi

    return 1
}

if [[ -z "$WINSCP_PATH" ]]; then
    info "Searching for WinSCP installation..."
    WINSCP_PATH=$(find_winscp) || die "WinSCP not found. Use --winscp-path to specify the location."
fi

[[ -f "$WINSCP_PATH/WinSCP.exe" ]] || die "WinSCP.exe not found in $WINSCP_PATH"
[[ -f "$WINSCP_PATH/WinSCP.ini" ]] || die "WinSCP.ini not found in $WINSCP_PATH (portable mode required)"
[[ -d "$WINE_PREFIX/drive_c" ]] || die "Wine prefix not found at $WINE_PREFIX"

ok "WinSCP found at: ${BOLD}$WINSCP_PATH${NC}"
ok "Wine prefix: ${BOLD}$WINE_PREFIX${NC}"

INI="$WINSCP_PATH/WinSCP.ini"
TOOLS_DIR="$WINE_PREFIX/drive_c/winscp-tools"
BIN_DIR="$HOME/.local/bin"
EXTENSION="$WINSCP_PATH/CompareFiles.WinSCPextension.bat"
WAIT_SCRIPT="$BIN_DIR/winscp-meld-wait"
BAT_FILE="$TOOLS_DIR/meld-ext.bat"

# --- Uninstall ---
if [[ "$UNINSTALL" -eq 1 ]]; then
    info "Uninstalling Compare Files extension..."

    rm -f "$EXTENSION" && ok "Removed extension file" || true
    rm -f "$WAIT_SCRIPT" && ok "Removed wait script" || true
    rm -f "$BAT_FILE" && ok "Removed bat wrapper" || true

    if grep -q 'commonext\\CompareFiles' "$INI" 2>/dev/null; then
        sed -i 's/ExtensionsDeleted=commonext\\CompareFiles/ExtensionsDeleted=/' "$INI"
        ok "Re-enabled built-in CompareFiles extension in WinSCP.ini"
    fi

    ok "Uninstall complete. Restart WinSCP to apply changes."
    exit 0
fi

# --- Check/Install Meld ---
install_meld() {
    local pm=""

    if command -v pacman &>/dev/null; then
        pm="pacman"
    elif command -v apt &>/dev/null; then
        pm="apt"
    elif command -v dnf &>/dev/null; then
        pm="dnf"
    elif command -v zypper &>/dev/null; then
        pm="zypper"
    fi

    if [[ -n "$pm" ]]; then
        echo ""
        read -rp "$(echo -e "${YELLOW}Install Meld using $pm? [Y/n]${NC} ")" answer
        answer="${answer:-y}"
        if [[ "$answer" =~ ^[Yy] ]]; then
            case "$pm" in
                pacman) sudo pacman -S --needed meld ;;
                apt)    sudo apt install -y meld ;;
                dnf)    sudo dnf install -y meld ;;
                zypper) sudo zypper install -y meld ;;
            esac
        else
            die "Meld is required. Install it manually and re-run this script."
        fi
    elif command -v flatpak &>/dev/null; then
        echo ""
        read -rp "$(echo -e "${YELLOW}Install Meld via Flatpak? [Y/n]${NC} ")" answer
        answer="${answer:-y}"
        if [[ "$answer" =~ ^[Yy] ]]; then
            flatpak install -y flathub org.gnome.meld
        else
            die "Meld is required. Install it manually and re-run this script."
        fi
    else
        die "No supported package manager found. Install Meld manually and re-run this script."
    fi
}

MELD_BIN=""
if command -v meld &>/dev/null; then
    MELD_BIN=$(command -v meld)
    ok "Meld found: ${BOLD}$MELD_BIN${NC}"
elif flatpak list 2>/dev/null | grep -q org.gnome.meld; then
    MELD_BIN="flatpak run org.gnome.meld"
    ok "Meld found (Flatpak)"
else
    warn "Meld is not installed."
    install_meld
    if command -v meld &>/dev/null; then
        MELD_BIN=$(command -v meld)
    elif flatpak list 2>/dev/null | grep -q org.gnome.meld; then
        MELD_BIN="flatpak run org.gnome.meld"
    else
        die "Meld installation failed."
    fi
    ok "Meld installed: ${BOLD}$MELD_BIN${NC}"
fi

# --- Backup WinSCP.ini ---
BACKUP="$INI.bak.$(date +%Y%m%d%H%M%S)"
cp "$INI" "$BACKUP"
ok "Backed up WinSCP.ini to ${BOLD}$(basename "$BACKUP")${NC}"

# --- Create directories ---
mkdir -p "$TOOLS_DIR" "$BIN_DIR"

# --- Create bat wrapper ---
# This runs inside Wine: copies the Wine-only temp file to /tmp,
# launches Meld, waits for it to close, copies changes back.
info "Creating bat wrapper..."
cat > "$BAT_FILE" << 'BATEOF'
@echo off
setlocal

set "REMOTE=%~1"
set "LOCAL=%~2"

rem Create temp dir on the Linux filesystem via Z: drive
set "TMPDIR=Z:\tmp\winscp-compare-%RANDOM%"
mkdir "%TMPDIR%"

rem Copy the remote temp file (only visible in Wine) to Linux filesystem
set "REMOTENAME=%~nx1"
copy "%REMOTE%" "%TMPDIR%\%REMOTENAME%" >nul

rem Launch meld (non-blocking) - wrapper creates .done marker when it closes
start "" /unix @WAIT_SCRIPT@ "%TMPDIR%" "%TMPDIR%\%REMOTENAME%" "%LOCAL%"

rem Wait for meld to close by polling for the .done marker
:waitloop
if exist "%TMPDIR%\.done" goto cleanup
ping -n 2 127.0.0.1 >nul
goto waitloop

:cleanup
rem Copy potentially modified file back to WinSCP temp so it detects the change and uploads
copy /y "%TMPDIR%\%REMOTENAME%" "%REMOTE%" >nul 2>&1
rmdir /s /q "%TMPDIR%" >nul 2>&1

endlocal
BATEOF

# Replace placeholder with actual path
sed -i "s|@WAIT_SCRIPT@|$WAIT_SCRIPT|g" "$BAT_FILE"
ok "Created: ${BOLD}$BAT_FILE${NC}"

# --- Create wait script ---
# Native Linux script that runs Meld and signals completion.
info "Creating wait script..."
cat > "$WAIT_SCRIPT" << WAITEOF
#!/bin/bash
# Wrapper: runs meld, creates .done marker when it exits
MARKER_DIR="\$1"; shift

convert_zpath() {
    local p="\$1"
    [[ "\$p" == [Zz]:* ]] && p="\${p:2}"
    echo "\${p//\\\\//}"
}

FILE1=\$(convert_zpath "\$1")
FILE2=\$(convert_zpath "\$2")

$MELD_BIN "\$FILE2" "\$FILE1" || true

MARKER_DIR=\$(convert_zpath "\$MARKER_DIR")
touch "\$MARKER_DIR/.done"
WAITEOF
chmod +x "$WAIT_SCRIPT"
ok "Created: ${BOLD}$WAIT_SCRIPT${NC}"

# --- Create extension file ---
# Convert WinSCP path to Wine path for the @command
# If WinSCP is under Wine's C: drive, use C: path
# If it's on the Linux filesystem, use Z: path
info "Creating extension file..."

TOOLS_WINPATH="C:\\\\winscp-tools"
cat > "$EXTENSION" << EXTEOF
rem @name         &Compare Files...
rem @command      ${TOOLS_WINPATH}\\meld-ext.bat ! !^!
rem @side         Local
rem @flag         ApplyToDirectories
rem @description  Compare local and remote file using Meld (Wine-compatible)
rem @version      3
rem @author       WinSCP Compare Installer
rem @require      WinSCP 5.13.4
rem @shortcut     Shift+Ctrl+Alt+C
EXTEOF
ok "Created: ${BOLD}$EXTENSION${NC}"

# --- Update WinSCP.ini ---
info "Updating WinSCP.ini..."

# Disable built-in CompareFiles extension
if grep -q '^ExtensionsDeleted=$' "$INI"; then
    sed -i '0,/^ExtensionsDeleted=$/s/^ExtensionsDeleted=$/ExtensionsDeleted=commonext\\CompareFiles/' "$INI"
    ok "Disabled built-in CompareFiles extension"
elif grep -q 'ExtensionsDeleted=commonext\\CompareFiles' "$INI"; then
    ok "Built-in CompareFiles already disabled"
else
    # ExtensionsDeleted has other values, append
    current=$(grep '^ExtensionsDeleted=' "$INI" | head -1 | cut -d= -f2-)
    if [[ -n "$current" && "$current" != "0" ]]; then
        sed -i "0,/^ExtensionsDeleted=/s/^ExtensionsDeleted=.*/ExtensionsDeleted=${current};commonext\\\\CompareFiles/" "$INI"
    else
        sed -i '0,/^ExtensionsDeleted=/s/^ExtensionsDeleted=.*/ExtensionsDeleted=commonext\\CompareFiles/' "$INI"
    fi
    ok "Disabled built-in CompareFiles extension"
fi

# Update ExtensionsPortableCount
if grep -q 'ExtensionsPortableCount=0' "$INI"; then
    sed -i 's/ExtensionsPortableCount=0/ExtensionsPortableCount=1/' "$INI"
    ok "Set ExtensionsPortableCount=1"
fi

# Add Meld custom command if not present
MELD_CMD="C:%5Cwinscp-tools%5Cmeld-ext.bat%20!%20!^!"
if ! grep -q '^\[Configuration\\CustomCommands\]' "$INI"; then
    warn "CustomCommands section not found in WinSCP.ini — skipping custom command setup"
elif ! grep -q "^Meld=" "$INI"; then
    sed -i "/^\[Configuration\\\\CustomCommands\]/a Meld=$MELD_CMD" "$INI"
    # Add params if section exists
    if grep -q '^\[Configuration\\CustomCommandsParams\]' "$INI"; then
        sed -i '/^\[Configuration\\CustomCommandsParams\]/a Meld=257' "$INI"
    fi
    ok "Added Meld custom command"
else
    ok "Meld custom command already present"
fi

# --- Summary ---
echo ""
echo -e "${GREEN}${BOLD}Installation complete!${NC}"
echo ""
echo "  Extension:    $EXTENSION"
echo "  Bat wrapper:  $BAT_FILE"
echo "  Wait script:  $WAIT_SCRIPT"
echo "  INI backup:   $BACKUP"
echo ""
echo -e "  ${BOLD}Restart WinSCP to activate.${NC}"
echo ""
echo "  Compare Files:  Commands > Compare Files (Shift+Ctrl+Alt+C)"
echo "  Meld command:   Commands > Custom Commands > Meld"
echo ""
echo "  To uninstall:   $0 --uninstall"