Add interactive session mode to keepassxc-cli.

This change adds a GNU Readline-based interactive mode to keepassxc-cli.
If GNU Readline is not available, commands are just read from stdin
with no editing support.

DatabaseCommand is modified to add the path to the current database to
the arguments passed to executeWithDatabase. In this way, instances of
DatabaseCommand do not have to prompt to re-open the database after each
invocation, and existing command implementations do not have to be
changed to support interactive mode.

Fixes keepassxreboot#3224.

cmake/FindReadline.cmake

@@ -0,0 +1,50 @@
+# Code copied from sethhall@github
+#
+# - Try to find readline include dirs and libraries
+#
+# Usage of this module as follows:
+#
+#     find_package(Readline)
+#
+# Variables used by this module, they can change the default behaviour and need
+# to be set before calling find_package:
+#
+#  Readline_ROOT_DIR         Set this variable to the root installation of
+#                            readline if the module has problems finding the
+#                            proper installation path.
+#
+# Variables defined by this module:
+#
+#  READLINE_FOUND            System has readline, include and lib dirs found
+#  Readline_INCLUDE_DIR      The readline include directories.
+#  Readline_LIBRARY          The readline library.
+
+find_path(Readline_ROOT_DIR
+    NAMES include/readline/readline.h
+)
+
+find_path(Readline_INCLUDE_DIR
+    NAMES readline/readline.h
+    HINTS ${Readline_ROOT_DIR}/include
+)
+
+find_library(Readline_LIBRARY
+    NAMES readline
+    HINTS ${Readline_ROOT_DIR}/lib
+)
+
+if(Readline_INCLUDE_DIR AND Readline_LIBRARY AND Ncurses_LIBRARY)
+  set(READLINE_FOUND TRUE)
+else(Readline_INCLUDE_DIR AND Readline_LIBRARY AND Ncurses_LIBRARY)
+  FIND_LIBRARY(Readline_LIBRARY NAMES readline)
+  include(FindPackageHandleStandardArgs)
+  FIND_PACKAGE_HANDLE_STANDARD_ARGS(Readline DEFAULT_MSG Readline_INCLUDE_DIR Readline_LIBRARY )
+  MARK_AS_ADVANCED(Readline_INCLUDE_DIR Readline_LIBRARY)
+endif(Readline_INCLUDE_DIR AND Readline_LIBRARY AND Ncurses_LIBRARY)
+
+mark_as_advanced(
+    Readline_ROOT_DIR
+    Readline_INCLUDE_DIR
+    Readline_LIBRARY
+)
+

src/cli/CMakeLists.txt

@@ -19,6 +19,7 @@ set(cli_SOURCES
         Clip.cpp
         Create.cpp
         Command.cpp
+        CommandParser.cpp
         DatabaseCommand.cpp
         Diceware.cpp
         Edit.cpp
@@ -28,12 +29,20 @@ set(cli_SOURCES
         List.cpp
         Locate.cpp
         Merge.cpp
+        Open.cpp
         Remove.cpp
         Show.cpp)
 
 add_library(cli STATIC ${cli_SOURCES})
 target_link_libraries(cli Qt5::Core Qt5::Widgets)
 
+find_package(Readline)
+
+if (READLINE_FOUND)
+    target_compile_definitions(cli PUBLIC USE_READLINE)
+    target_link_libraries(cli readline)
+endif()
+
 add_executable(keepassxc-cli keepassxc-cli.cpp)
 target_link_libraries(keepassxc-cli
         cli

src/cli/Command.cpp

@@ -34,6 +34,7 @@
 #include "List.h"
 #include "Locate.h"
 #include "Merge.h"
+#include "Open.h"
 #include "Remove.h"
 #include "Show.h"
 #include "TextStream.h"
@@ -119,6 +120,7 @@ void populateCommands()
         commands.insert(QString("locate"), new Locate());
         commands.insert(QString("ls"), new List());
         commands.insert(QString("merge"), new Merge());
+        commands.insert(QString("open"), new Open());
         commands.insert(QString("rm"), new Remove());
         commands.insert(QString("show"), new Show());
     }

src/cli/Command.h

@@ -44,6 +44,7 @@ class Command
     virtual int execute(const QStringList& arguments) = 0;
     QString name;
     QString description;
+    QSharedPointer<Database> currentDatabase;
     QList<CommandLineArgument> positionalArguments;
     QList<CommandLineArgument> optionalArguments;
     QList<QCommandLineOption> options;

src/cli/CommandParser.cpp

@@ -0,0 +1,48 @@
+/*
+ *  Copyright (C) 2019 KeePassXC Team <[email protected]>
+ *
+ *  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 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  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/>.
+ */
+
+#include "CommandParser.h"
+
+QStringList const CommandParser::parse(const QString& command)
+{
+    QStringList result;
+
+    bool inside_quotes = false;
+    QString cur;
+    for (int i = 0; i < command.size(); ++i) {
+        QChar c = command[i];
+        if (c == '\\' && i < command.size() - 1) {
+            cur.append(command[i + 1]);
+            ++i;
+        } else if (!inside_quotes && (c == ' ' || c == '\t')) {
+            if (!cur.isEmpty()) {
+                result.append(cur);
+                cur.clear();
+            }
+        } else if (c == '"' && (inside_quotes || i == 0 || command[i - 1].isSpace())) {
+            inside_quotes = !inside_quotes;
+        } else {
+            cur.append(c);
+        }
+    }
+
+    if (!cur.isEmpty()) {
+        result.append(cur);
+    }
+
+    return result;
+}

src/cli/CommandParser.h

@@ -0,0 +1,38 @@
+/*
+ *  Copyright (C) 2019 KeePassXC Team <[email protected]>
+ *
+ *  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 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  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/>.
+ */
+
+#ifndef KEEPASSXC_COMMANDPARSER_H
+#define KEEPASSXC_COMMANDPARSER_H
+
+#include <QtCore/QStringList>
+
+// Implements basic string splitting for the readline-based interactive CLI.
+class CommandParser
+{
+public:
+    CommandParser() = default;
+
+    // Splits the given QString into a QString list. For example:
+    //
+    // "hello world" -> ["hello", "world"]
+    // "hello    world" -> ["hello", "world"]
+    // "hello\\ world" -> ["hello world"] (i.e. backslash is an escape character
+    // "\"hello world\"" -> ["hello world"]
+    QStringList const parse(const QString& command);
+};
+
+#endif // KEEPASSXC_COMMANDPARSER_H

src/cli/DatabaseCommand.cpp

@@ -28,20 +28,28 @@ DatabaseCommand::DatabaseCommand()
 
 int DatabaseCommand::execute(const QStringList& arguments)
 {
-    QSharedPointer<QCommandLineParser> parser = getCommandLineParser(arguments);
+    QStringList amendedArgs(arguments);
+    if (currentDatabase) {
+        amendedArgs.prepend(currentDatabase->filePath());
+    }
+    QSharedPointer<QCommandLineParser> parser = getCommandLineParser(amendedArgs);
+
     if (parser.isNull()) {
         return EXIT_FAILURE;
     }
 
-    const QStringList args = parser->positionalArguments();
-    auto db = Utils::unlockDatabase(args.at(0),
-                                    !parser->isSet(Command::NoPasswordOption),
-                                    parser->value(Command::KeyFileOption),
-                                    parser->isSet(Command::QuietOption) ? Utils::DEVNULL : Utils::STDOUT,
-                                    Utils::STDERR);
-    if (!db) {
-        return EXIT_FAILURE;
+    QStringList args = parser->positionalArguments();
+    if (!currentDatabase) {
+        currentDatabase = Utils::unlockDatabase(args.at(0),
+                                   !parser->isSet(Command::NoPasswordOption),
+                                   parser->value(Command::KeyFileOption),
+                                   parser->isSet(Command::QuietOption)
+                                   ? Utils::DEVNULL : Utils::STDOUT,
+                                   Utils::STDERR);
+      if (!currentDatabase) {
+          return EXIT_FAILURE;
+      }
     }
 
-    return executeWithDatabase(db, parser);
+    return executeWithDatabase(currentDatabase, parser);
 }

src/cli/Open.cpp

@@ -0,0 +1,37 @@
+/*
+ *  Copyright (C) 2019 KeePassXC Team <[email protected]>
+ *
+ *  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 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  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/>.
+ */
+
+#include "Open.h"
+
+#include <QtCore/QCommandLineParser>
+
+#include "DatabaseCommand.h"
+#include "TextStream.h"
+#include "Utils.h"
+
+Open::Open()
+{
+    name = QString("open");
+    description = QObject::tr("Open a database.");
+}
+
+int Open::executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser)
+{
+    Q_UNUSED(parser)
+    currentDatabase = db;
+    return EXIT_SUCCESS;
+}

src/cli/Open.h

@@ -0,0 +1,31 @@
+/*
+ *  Copyright (C) 2019 KeePassXC Team <[email protected]>
+ *
+ *  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 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  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/>.
+ */
+
+#ifndef KEEPASSXC_OPEN_H
+#define KEEPASSXC_OPEN_H
+
+#include "DatabaseCommand.h"
+
+class Open : public DatabaseCommand
+{
+public:
+    Open();
+    ~Open() override = default;
+    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser) override;
+};
+
+#endif // KEEPASSXC_OPEN_H