Add readline support to cli

This PR adds readline support to the daemon and monero-wallet-cli. Only
GNU readline is supported (e.g. not libedit) and there are cmake checks
to ensure this.

There is a cmake variable, Readline_ROOT_DIR that can specify a
directory to find readline, otherwise some default paths are searched.

There is also a cmake option, USE_READLINE, that defaults to ON. If set
to ON, if readline is not found, the build continues but without
readline support.

One negative side effect of using readline is that the color prompt in
the wallet-cli now has no color and just uses terminal default. I know
how to fix this but it's quite a big change so will tackle another time.

8 files changed, 376 insertions, 1 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a9d6be986..a8060f90c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -655,6 +655,19 @@ endif()
 
 list(APPEND EXTRA_LIBRARIES ${CMAKE_DL_LIBS})
 
+option(USE_READLINE "Build with GNU readline support." ON)
+if(USE_READLINE)
+  find_package(Readline)
+  if(READLINE_FOUND AND GNU_READLINE_FOUND)
+    add_definitions(-DHAVE_READLINE)
+    include_directories(${Readline_INCLUDE_DIR})
+    list(APPEND EXTRA_LIBRARIES ${Readline_LIBRARY})
+    message(STATUS "Found readline library at: ${Readline_ROOT_DIR}")
+  else()
+    message(STATUS "Could not find GNU readline library so building without readline support")
+  endif()
+endif()
+
 if(ANDROID)
   set(ATOMIC libatomic.a)
 endif()
diff --git a/cmake/FindReadline.cmake b/cmake/FindReadline.cmake
new file mode 100644
index 000000000..9ccef7ad8
--- /dev/null
+++ b/cmake/FindReadline.cmake
@@ -0,0 +1,66 @@
+# - 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
+#  GNU_READLINE_FOUND        Version of readline found is GNU readline, not libedit!
+#  Readline_INCLUDE_DIR      The readline include directories. 
+#  Readline_LIBRARY          The readline library.
+
+find_path(Readline_ROOT_DIR
+    NAMES include/readline/readline.h
+    PATHS /opt/local/ /usr/local/ /usr/
+    NO_DEFAULT_PATH
+)
+
+find_path(Readline_INCLUDE_DIR
+    NAMES readline/readline.h
+    PATHS ${Readline_ROOT_DIR}/include
+    NO_DEFAULT_PATH
+)
+
+find_library(Readline_LIBRARY
+    NAMES readline
+    PATHS ${Readline_ROOT_DIR}/lib
+    NO_DEFAULT_PATH
+)
+
+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 PATHS Readline_ROOT_DIR)
+  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
+)
+
+set(CMAKE_REQUIRED_INCLUDES ${Readline_INCLUDE_DIR})
+set(CMAKE_REQUIRED_LIBRARIES ${Readline_LIBRARY})
+INCLUDE(CheckCXXSourceCompiles) 
+CHECK_CXX_SOURCE_COMPILES(
+"
+#include <stdio.h>
+#include <readline/readline.h>
+int
+main()
+{
+  char * s  = rl_copy_text(0, 0);
+}
+" GNU_READLINE_FOUND)
diff --git a/contrib/epee/include/console_handler.h b/contrib/epee/include/console_handler.h
index 54e3e966d..bb20faa65 100644
--- a/contrib/epee/include/console_handler.h
+++ b/contrib/epee/include/console_handler.h
@@ -38,6 +38,10 @@
 #endif
 #include <boost/thread.hpp>
 
+#ifdef HAVE_READLINE
+  #include "readline_buffer.h"
+#endif
+
 namespace epee
 {
   class async_stdin_reader
@@ -49,6 +53,10 @@ namespace epee
       , m_read_status(state_init)
     {
       m_reader_thread = boost::thread(std::bind(&async_stdin_reader::reader_thread_func, this));
+#ifdef HAVE_READLINE
+      m_readline_buffer.start();
+      m_readline_thread = boost::thread(std::bind(&async_stdin_reader::readline_thread_func, this));
+#endif
     }
 
     ~async_stdin_reader()
@@ -56,6 +64,13 @@ namespace epee
       stop();
     }
 
+#ifdef HAVE_READLINE
+    rdln::readline_buffer& get_readline_buffer()
+    {
+      return m_readline_buffer;
+    }
+#endif
+
     // Not thread safe. Only one thread can call this method at once.
     bool get_line(std::string& line)
     {
@@ -98,6 +113,10 @@ namespace epee
 
         m_request_cv.notify_one();
         m_reader_thread.join();
+#ifdef HAVE_READLINE
+        m_readline_buffer.stop();
+        m_readline_thread.join();
+#endif
       }
     }
 
@@ -174,6 +193,16 @@ namespace epee
       return true;
     }
 
+#ifdef HAVE_READLINE
+    void readline_thread_func()
+    {
+      while (m_run.load(std::memory_order_relaxed))
+      {
+        m_readline_buffer.process();
+      }
+    }
+#endif
+
     void reader_thread_func()
     {
       while (true)
@@ -187,7 +216,11 @@ namespace epee
         {
           if (m_run.load(std::memory_order_relaxed))
           {
+#ifdef HAVE_READLINE
+            m_readline_buffer.get_line(line);
+#else
             std::getline(std::cin, line);
+#endif
             read_ok = !std::cin.eof() && !std::cin.fail();
           }
         }
@@ -229,6 +262,10 @@ namespace epee
   private:
     boost::thread m_reader_thread;
     std::atomic<bool> m_run;
+#ifdef HAVE_READLINE
+    boost::thread m_readline_thread;
+    rdln::readline_buffer m_readline_buffer;
+#endif
 
     std::string m_line;
     bool m_has_read_request;
@@ -277,12 +314,16 @@ namespace epee
     {
       if (!m_prompt.empty())
       {
+#ifdef HAVE_READLINE
+        m_stdin_reader.get_readline_buffer().set_prompt(m_prompt);
+#else
         epee::set_console_color(epee::console_color_yellow, true);
         std::cout << m_prompt;
         if (' ' != m_prompt.back())
           std::cout << ' ';
         epee::reset_console_color();
         std::cout.flush();
+#endif
       }
     }
 
diff --git a/contrib/epee/include/readline_buffer.h b/contrib/epee/include/readline_buffer.h
new file mode 100644
index 000000000..7d929bc4c
--- /dev/null
+++ b/contrib/epee/include/readline_buffer.h
@@ -0,0 +1,40 @@
+#pragma once
+
+#include <streambuf>
+#include <sstream>
+#include <iostream>
+
+namespace rdln
+{
+  class readline_buffer : public std::stringbuf
+  {
+  public:
+    readline_buffer();
+    void start();
+    void stop();
+    int process();
+    bool is_running()
+    {
+      return m_cout_buf != NULL;
+    }
+    void get_line(std::string& line);
+    void set_prompt(const std::string& prompt);
+    
+  protected:
+    virtual int sync();
+    
+  private:
+    std::streambuf* m_cout_buf;
+  };
+  
+  class suspend_readline
+  {
+  public:
+    suspend_readline();
+    ~suspend_readline();
+  private:
+    readline_buffer* m_buffer;
+    bool m_restart;
+  };
+}
+
diff --git a/contrib/epee/src/CMakeLists.txt b/contrib/epee/src/CMakeLists.txt
index 437851833..c61a6e684 100644
--- a/contrib/epee/src/CMakeLists.txt
+++ b/contrib/epee/src/CMakeLists.txt
@@ -26,7 +26,12 @@
 # STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 # THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-add_library(epee STATIC hex.cpp http_auth.cpp mlog.cpp string_tools.cpp)
+if (USE_READLINE AND GNU_READLINE_FOUND)
+  add_library(epee STATIC hex.cpp http_auth.cpp mlog.cpp string_tools.cpp readline_buffer.cpp)
+else()
+  add_library(epee STATIC hex.cpp http_auth.cpp mlog.cpp string_tools.cpp)
+endif()
+
 # Build and install libepee if we're building for GUI
 if (BUILD_GUI_DEPS)
     if(IOS)
diff --git a/contrib/epee/src/readline_buffer.cpp b/contrib/epee/src/readline_buffer.cpp
new file mode 100644
index 000000000..68b739db9
--- /dev/null
+++ b/contrib/epee/src/readline_buffer.cpp
@@ -0,0 +1,196 @@
+#include "readline_buffer.h"
+#include <readline/readline.h>
+#include <readline/history.h>
+#include <sys/select.h>
+#include <unistd.h>
+#include <mutex>
+#include <condition_variable>
+
+static int process_input();
+static void install_line_handler();
+static void remove_line_handler();
+
+static std::string last_line;
+static std::string last_prompt;
+std::mutex line_mutex, sync_mutex;
+std::condition_variable have_line;
+
+namespace
+{
+  rdln::readline_buffer* current = NULL;
+}
+
+rdln::suspend_readline::suspend_readline()
+{
+  m_buffer = current;
+  if(!m_buffer)
+    return;
+  m_restart = m_buffer->is_running();
+  if(m_restart)
+    m_buffer->stop();
+}
+
+rdln::suspend_readline::~suspend_readline()
+{
+  if(!m_buffer)
+    return;
+  if(m_restart)
+    m_buffer->start();
+}
+
+rdln::readline_buffer::readline_buffer()
+: std::stringbuf()
+{
+  current = this;
+}
+
+void rdln::readline_buffer::start()
+{
+  if(m_cout_buf != NULL)
+    return;
+  m_cout_buf = std::cout.rdbuf();
+  std::cout.rdbuf(this);
+  install_line_handler();
+}
+
+void rdln::readline_buffer::stop()
+{
+  if(m_cout_buf == NULL)
+    return;
+  std::cout.rdbuf(m_cout_buf);
+  m_cout_buf = NULL;
+  remove_line_handler();
+}
+
+void rdln::readline_buffer::get_line(std::string& line)
+{
+  std::unique_lock<std::mutex> lock(line_mutex);
+  have_line.wait(lock);
+  line = last_line;
+}
+
+void rdln::readline_buffer::set_prompt(const std::string& prompt)
+{
+  last_prompt = prompt;
+  if(m_cout_buf == NULL)
+    return;
+  rl_set_prompt(last_prompt.c_str());
+  rl_redisplay();
+}
+
+int rdln::readline_buffer::process()
+{
+  if(m_cout_buf == NULL)
+    return 0;
+  return process_input();
+}
+
+int rdln::readline_buffer::sync()
+{
+  std::lock_guard<std::mutex> lock(sync_mutex);
+  char* saved_line;
+  int saved_point;
+  
+  saved_point = rl_point;
+  saved_line = rl_copy_text(0, rl_end);
+  
+  rl_set_prompt("");
+  rl_replace_line("", 0);
+  rl_redisplay();
+  
+  do
+  {
+    char x = this->sgetc();
+    m_cout_buf->sputc(x);
+  }
+  while ( this->snextc() != EOF );
+  
+  rl_set_prompt(last_prompt.c_str());
+  rl_replace_line(saved_line, 0);
+  rl_point = saved_point;
+  rl_redisplay();
+  free(saved_line);
+  
+  return 0;
+}
+
+static fd_set fds;
+
+static int process_input()
+{
+  int count;
+  struct timeval t;
+  
+  t.tv_sec = 0;
+  t.tv_usec = 0;
+  
+  FD_ZERO(&fds);
+  FD_SET(STDIN_FILENO, &fds);
+  count = select(FD_SETSIZE, &fds, NULL, NULL, &t);
+  if (count < 1)
+  {
+    return count;
+  }
+  rl_callback_read_char();
+  return count;
+}
+
+static void handle_line(char* line)
+{
+  if (line != NULL)
+  {
+    std::lock_guard<std::mutex> lock(sync_mutex);
+    rl_set_prompt(last_prompt.c_str());
+    rl_already_prompted = 1;
+    return;
+  }
+  rl_set_prompt("");
+  rl_replace_line("", 0);
+  rl_redisplay();
+  rl_set_prompt(last_prompt.c_str());
+}
+
+static int handle_enter(int x, int y)
+{
+  std::lock_guard<std::mutex> lock(sync_mutex);
+  char* line = NULL;
+  
+  line = rl_copy_text(0, rl_end);
+  rl_set_prompt("");
+  rl_replace_line("", 1);
+  rl_redisplay();
+  
+  if (strcmp(line, "") != 0)
+  {
+    last_line = line;
+    add_history(line);
+    have_line.notify_one();
+  }
+  free(line);
+  
+  rl_set_prompt(last_prompt.c_str());
+  rl_redisplay();
+  
+  rl_done = 1;
+  return 0;
+}
+
+static int startup_hook()
+{
+  rl_bind_key(RETURN, handle_enter);
+  rl_bind_key(NEWLINE, handle_enter);
+  return 0;
+}
+
+static void install_line_handler()
+{
+  rl_startup_hook = startup_hook;
+  rl_callback_handler_install("", handle_line);
+}
+
+static void remove_line_handler()
+{
+  rl_unbind_key(RETURN);
+  rl_callback_handler_remove();
+}
+
diff --git a/src/common/command_line.cpp b/src/common/command_line.cpp
index f71b3e576..8c2796bbe 100644
--- a/src/common/command_line.cpp
+++ b/src/common/command_line.cpp
@@ -37,6 +37,10 @@
 #include "cryptonote_config.h"
 #include "string_tools.h"
 
+#ifdef HAVE_READLINE
+  #include "readline_buffer.h"
+#endif
+
 namespace command_line
 {
   namespace
@@ -49,6 +53,9 @@ namespace command_line
 
   std::string input_line(const std::string& prompt)
   {
+#ifdef HAVE_READLINE
+    rdln::suspend_readline pause_readline;
+#endif
     std::cout << prompt;
 
     std::string buf;
diff --git a/src/common/password.cpp b/src/common/password.cpp
index bdc9c69c0..5c04023f4 100644
--- a/src/common/password.cpp
+++ b/src/common/password.cpp
@@ -42,6 +42,10 @@
 #include <unistd.h>
 #endif
 
+#ifdef HAVE_READLINE
+  #include "readline_buffer.h"
+#endif
+
 namespace
 {
 #if defined(_WIN32)
@@ -238,6 +242,9 @@ namespace tools
 
   boost::optional<password_container> password_container::prompt(const bool verify, const char *message)
   {
+#ifdef HAVE_READLINE
+    rdln::suspend_readline pause_readline;
+#endif
     password_container pass1{};
     password_container pass2{};
     if (is_cin_tty() ? read_from_tty(verify, message, pass1.m_password, pass2.m_password) : read_from_file(pass1.m_password))