[4/7] gdb/ui-file: Add newline tracking

diff --git a/gdb/cli-out.c b/gdb/cli-out.c
index fdfd0f7f0cf..1639f885cb9 100644
--- a/gdb/cli-out.c
+++ b/gdb/cli-out.c
@@ -307,6 +307,10 @@  cli_ui_out::do_progress_notify (const std::string &msg,
 
   if (info.state == progress_update::START)
     {
+      /* MSG should print on its own line.  */
+      if (stream->get_line_state () == ui_file::LINE_NOT_AT_START)
+	gdb_printf (stream, "\n");
+
       if (stream->isatty ()
 	  && current_ui->input_interactive_p ()
 	  && chars_per_line >= MIN_CHARS_PER_LINE)
@@ -410,10 +414,18 @@  void
 cli_ui_out::do_progress_end ()
 {
   struct ui_file *stream = m_streams.back ();
-  m_progress_info.pop_back ();
 
-  if (stream->isatty ())
-    clear_current_line ();
+  cli_progress_info &info (m_progress_info.back ());
+
+  if (info.state != progress_update::START && stream->isatty ())
+    {
+      clear_current_line ();
+
+      if (stream->get_line_state () != ui_file::LINE_UNDEFINED)
+	stream->set_line_state (ui_file::LINE_AT_START);
+    }
+
+  m_progress_info.pop_back ();
 }
 
 /* local functions */
diff --git a/gdb/mi/mi-console.c b/gdb/mi/mi-console.c
index e0b5648c2df..60f2a823b47 100644
--- a/gdb/mi/mi-console.c
+++ b/gdb/mi/mi-console.c
@@ -46,6 +46,8 @@  mi_console_file::write (const char *buf, long length_buf)
      buffer.  */
   if (strchr (m_buffer.c_str () + prev_size, '\n') != NULL)
     this->flush ();
+
+  set_line_state_from_buf (m_buffer.c_str () + prev_size, length_buf);
 }
 
 void
@@ -63,6 +65,8 @@  mi_console_file::write_async_safe (const char *buf, long length_buf)
 
   char nl = '\n';
   m_raw->write_async_safe (&nl, 1);
+
+  set_line_state (LINE_AT_START);
 }
 
 void
diff --git a/gdb/tui/tui-file.c b/gdb/tui/tui-file.c
index c1619d5ace6..c36ce739497 100644
--- a/gdb/tui/tui-file.c
+++ b/gdb/tui/tui-file.c
@@ -28,6 +28,8 @@  tui_file::puts (const char *linebuffer)
   tui_puts (linebuffer);
   if (!m_buffered)
     tui_refresh_cmd_win ();
+
+  set_line_state_from_buf (linebuffer);
 }
 
 void
@@ -36,6 +38,8 @@  tui_file::write (const char *buf, long length_buf)
   tui_write (buf, length_buf);
   if (!m_buffered)
     tui_refresh_cmd_win ();
+
+  set_line_state_from_buf (buf, length_buf);
 }
 
 void
diff --git a/gdb/ui-file.c b/gdb/ui-file.c
index e0814fe2b2d..3f7a55ed252 100644
--- a/gdb/ui-file.c
+++ b/gdb/ui-file.c
@@ -31,6 +31,7 @@ 
 null_file null_stream;
 
 ui_file::ui_file ()
+  : m_line_state (LINE_UNDEFINED)
 {}
 
 ui_file::~ui_file ()
@@ -159,6 +160,30 @@  ui_file::printchar (int c, int quoter, bool async_safe)
     this->write (buf, out);
 }
 
+/* See ui-file.h.  */
+
+void
+ui_file::set_line_state_from_buf (const char *buf)
+{
+  const char *last_nl = strrchr (buf, '\n');
+
+  if (last_nl != nullptr && *++last_nl == '\0')
+    m_line_state = LINE_AT_START;
+  else
+    m_line_state = LINE_NOT_AT_START;
+}
+
+/* See ui-file.h.  */
+
+void
+ui_file::set_line_state_from_buf (const char *buf, long length_buf)
+{
+  if (buf[length_buf - 1] == '\n')
+    m_line_state = LINE_AT_START;
+  else
+    m_line_state = LINE_NOT_AT_START;
+}
+
 
 
 void
@@ -311,6 +336,8 @@  stdio_file::write (const char *buf, long length_buf)
     {
       /* Nothing.  */
     }
+
+  set_line_state_from_buf (buf, length_buf);
 }
 
 void
@@ -323,6 +350,8 @@  stdio_file::write_async_safe (const char *buf, long length_buf)
     {
       /* Nothing.  */
     }
+
+  set_line_state_from_buf (buf, length_buf);
 }
 
 void
@@ -339,6 +368,8 @@  stdio_file::puts (const char *linebuffer)
     {
       /* Nothing.  */
     }
+
+  set_line_state_from_buf (linebuffer);
 }
 
 bool
diff --git a/gdb/ui-file.h b/gdb/ui-file.h
index de24620e247..b85c37d81c7 100644
--- a/gdb/ui-file.h
+++ b/gdb/ui-file.h
@@ -132,11 +132,40 @@  class ui_file
     this->puts (str);
   }
 
+  enum line_state
+  {
+    /* Line state is not being tracked.  */
+    LINE_UNDEFINED,
+
+    /* The last character written to this ui_file is not a newline.  */
+    LINE_NOT_AT_START,
+
+    /* The last character written to this ui_file is a newline.  */
+    LINE_AT_START
+  };
+
+  /* Set this ui_file's line_state to STATE.  */
+  virtual void set_line_state (line_state state)
+  { m_line_state = state; }
+
+  /* Return this ui_file's line_state.  */
+  virtual line_state get_line_state ()
+  { return m_line_state; }
+
 protected:
 
   /* The currently applied style.  */
   ui_file_style m_applied_style;
 
+  /* The current line_state.  */
+  line_state m_line_state;
+
+  /* Set line_state based on whether BUF ends in a newline.  */
+  void set_line_state_from_buf (const char *buf);
+
+  /* Set line_state based on whether BUF ends in a newline.  */
+  void set_line_state_from_buf (const char *buf, long length_buf);
+
 private:
 
   /* Helper function for putstr and putstrn.  Print the character C on
@@ -428,6 +457,21 @@  class wrapped_file : public ui_file
   void write_async_safe (const char *buf, long length_buf) override
   { return m_stream->write_async_safe (buf, length_buf); }
 
+  /* Return the line_state of the underlying stream.  */
+  line_state get_line_state () override
+  {
+    if (m_stream == nullptr)
+      return ui_file::LINE_UNDEFINED;
+    return m_stream->get_line_state ();
+  }
+
+  /* Set the line_state of the underlying stream.  */
+  void set_line_state (line_state state) override
+  {
+    if (m_stream != nullptr)
+      m_stream->set_line_state (state);
+  }
+
 protected:
 
   /* Note that this class does not assume ownership of the stream.