Merge PR #1060 'Implement --embedded-mode command-line option'

9 files changed, 156 insertions, 22 deletions

diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 74f3edc8d9..69fb1d344a 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -2011,6 +2011,10 @@ void free_cmdline_buf(void)
  */
 static void draw_cmdline(int start, int len)
 {
+  if (embedded_mode) {
+    return;
+  }
+
   int i;
 
   if (cmdline_star > 0)
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index ad65f7e6fd..1ff8887598 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -1233,6 +1233,9 @@ EXTERN char *ignoredp;
  * os_unix.c */
 EXTERN int curr_tmode INIT(= TMODE_COOK); /* contains current terminal mode */
 
+// If a msgpack-rpc channel should be started over stdin/stdout
+EXTERN bool embedded_mode INIT(= false);
+
 /// Used to track the status of external functions.
 /// Currently only used for iconv().
 typedef enum {
diff --git a/src/nvim/main.c b/src/nvim/main.c
index 1de4b04a07..2f06a2cbf2 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -256,10 +256,10 @@ int main(int argc, char **argv)
   TIME_MSG("shell init");
 
 
-  /*
-   * Print a warning if stdout is not a terminal.
-   */
-  check_tty(&params);
+  if (!embedded_mode) {
+    // Print a warning if stdout is not a terminal.
+    check_tty(&params);
+  }
 
   /* This message comes before term inits, but after setting "silent_mode"
    * when the input is not a tty. */
@@ -267,8 +267,16 @@ int main(int argc, char **argv)
     printf(_("%d files to edit\n"), GARGCOUNT);
 
   if (params.want_full_screen && !silent_mode) {
-    termcapinit(params.term);           /* set terminal name and get terminal
-                                           capabilities (will set full_screen) */
+    if (embedded_mode) {
+      // In embedded mode don't do terminal-related initializations, assume an
+      // initial screen size of 80x20
+      full_screen = true;
+      set_shellsize(80, 20, false);
+    } else { 
+      // set terminal name and get terminal capabilities (will set full_screen)
+      // Do some initialization of the screen
+      termcapinit(params.term);
+    }
     screen_start();             /* don't know where cursor is now */
     TIME_MSG("Termcap init");
   }
@@ -405,14 +413,18 @@ int main(int argc, char **argv)
     TIME_MSG("waiting for return");
   }
 
-  starttermcap();             /* start termcap if not done by wait_return() */
-  TIME_MSG("start termcap");
-  may_req_ambiguous_char_width();
+  if (!embedded_mode) {
+    starttermcap(); // start termcap if not done by wait_return()
+    TIME_MSG("start termcap");
+    may_req_ambiguous_char_width();
+    setmouse();  // may start using the mouse
 
-  setmouse();                             /* may start using the mouse */
-  if (scroll_region)
-    scroll_region_reset();                /* In case Rows changed */
-  scroll_start();         /* may scroll the screen to the right position */
+    if (scroll_region) {
+      scroll_region_reset(); // In case Rows changed
+    }
+
+    scroll_start(); // may scroll the screen to the right position
+  }
 
   /*
    * Don't clear the screen when starting in Ex mode, unless using the GUI.
@@ -1015,11 +1027,13 @@ static void command_line_scan(mparm_T *parmp)
             msg_putchar('\n');
             msg_didout = FALSE;
             mch_exit(0);
-	  } else if (STRICMP(argv[0] + argv_idx, "api-msgpack-metadata") == 0) {
+          } else if (STRICMP(argv[0] + argv_idx, "api-msgpack-metadata") == 0) {
             for (unsigned int i = 0; i<msgpack_metadata_size; i++) {
               putchar(msgpack_metadata[i]);
             }
             mch_exit(0);
+          } else if (STRICMP(argv[0] + argv_idx, "embedded-mode") == 0) {
+            embedded_mode = true;
           } else if (STRNICMP(argv[0] + argv_idx, "literal", 7) == 0) {
 #if !defined(UNIX)
             parmp->literal = TRUE;
@@ -2200,6 +2214,8 @@ static void usage(void)
   main_msg(_("--startuptime <file>\tWrite startup timing messages to <file>"));
   main_msg(_("-i <viminfo>\t\tUse <viminfo> instead of .viminfo"));
   main_msg(_("--api-msgpack-metadata\tDump API metadata information and exit"));
+  main_msg(_("--embedded-mode\tUse stdin/stdout as a msgpack-rpc channel. "
+             "This can be used for embedding Neovim into other programs"));
   main_msg(_("-h  or  --help\tPrint Help (this message) and exit"));
   main_msg(_("--version\t\tPrint version information and exit"));
 
diff --git a/src/nvim/os/channel.c b/src/nvim/os/channel.c
index 1a2efca513..2c1928f3b3 100644
--- a/src/nvim/os/channel.c
+++ b/src/nvim/os/channel.c
@@ -20,11 +20,14 @@
 #include "nvim/vim.h"
 #include "nvim/ascii.h"
 #include "nvim/memory.h"
+#include "nvim/os_unix.h"
 #include "nvim/message.h"
 #include "nvim/map.h"
 #include "nvim/log.h"
 #include "nvim/lib/kvec.h"
 
+#define CHANNEL_BUFFER_SIZE 0xffff
+
 typedef struct {
   uint64_t request_id;
   bool errored;
@@ -64,6 +67,10 @@ void channel_init(void)
   channels = pmap_new(uint64_t)();
   event_strings = pmap_new(cstr_t)();
   msgpack_sbuffer_init(&out_buffer);
+
+  if (embedded_mode) {
+    channel_from_stdio();
+  }
 }
 
 /// Teardown the module
@@ -117,7 +124,10 @@ void channel_from_stream(uv_stream_t *stream)
   stream->data = NULL;
   channel->is_job = false;
   // read stream
-  channel->data.streams.read = rstream_new(parse_msgpack, 1024, channel, NULL);
+  channel->data.streams.read = rstream_new(parse_msgpack,
+                                           CHANNEL_BUFFER_SIZE,
+                                           channel,
+                                           NULL);
   rstream_set_stream(channel->data.streams.read, stream);
   rstream_start(channel->data.streams.read);
   // write stream
@@ -256,6 +266,25 @@ void channel_unsubscribe(uint64_t id, char *event)
   unsubscribe(channel, event);
 }
 
+/// Creates an API channel from stdin/stdout. This is used when embedding
+/// Neovim
+static void channel_from_stdio(void)
+{
+  Channel *channel = register_channel();
+  channel->is_job = false;
+  // read stream
+  channel->data.streams.read = rstream_new(parse_msgpack,
+                                           CHANNEL_BUFFER_SIZE,
+                                           channel,
+                                           NULL);
+  rstream_set_file(channel->data.streams.read, 0);
+  rstream_start(channel->data.streams.read);
+  // write stream
+  channel->data.streams.write = wstream_new(0);
+  wstream_set_file(channel->data.streams.write, 1);
+  channel->data.streams.uv = NULL;
+}
+
 static void job_out(RStream *rstream, void *data, bool eof)
 {
   Job *job = data;
@@ -278,6 +307,7 @@ static void job_err(RStream *rstream, void *data, bool eof)
 static void parse_msgpack(RStream *rstream, void *data, bool eof)
 {
   Channel *channel = data;
+  channel->rpc_call_level++;
 
   if (eof) {
     char buf[256];
@@ -287,10 +317,9 @@ static void parse_msgpack(RStream *rstream, void *data, bool eof)
              "closed by the client",
              channel->id);
     call_set_error(channel, buf);
-    return;
+    goto end;
   }
 
-  channel->rpc_call_level++;
   uint32_t count = rstream_available(rstream);
   DLOG("Feeding the msgpack parser with %u bytes of data from RStream(%p)",
        count,
@@ -469,7 +498,12 @@ static void close_channel(Channel *channel)
   } else {
     rstream_free(channel->data.streams.read);
     wstream_free(channel->data.streams.write);
-    uv_close((uv_handle_t *)channel->data.streams.uv, close_cb);
+    if (channel->data.streams.uv) {
+      uv_close((uv_handle_t *)channel->data.streams.uv, close_cb);
+    } else {
+      // When the stdin channel closes, it's time to go
+      mch_exit(0);
+    }
   }
 
   free(channel);
diff --git a/src/nvim/os/input.c b/src/nvim/os/input.c
index 15aebdbf3d..53024d1389 100644
--- a/src/nvim/os/input.c
+++ b/src/nvim/os/input.c
@@ -6,6 +6,7 @@
 
 #include "nvim/os/input.h"
 #include "nvim/os/event.h"
+#include "nvim/os/signal.h"
 #include "nvim/os/rstream_defs.h"
 #include "nvim/os/rstream.h"
 #include "nvim/ascii.h"
@@ -34,6 +35,10 @@ static bool eof = false, started_reading = false;
 
 void input_init(void)
 {
+  if (embedded_mode) {
+    return;
+  }
+
   read_stream = rstream_new(read_cb, READ_BUFFER_SIZE, NULL, NULL);
   rstream_set_file(read_stream, read_cmd_fd);
 }
@@ -41,18 +46,30 @@ void input_init(void)
 // Listen for input
 void input_start(void)
 {
+  if (embedded_mode) {
+    return;
+  }
+
   rstream_start(read_stream);
 }
 
 // Stop listening for input
 void input_stop(void)
 {
+  if (embedded_mode) {
+    return;
+  }
+
   rstream_stop(read_stream);
 }
 
 // Copies (at most `count`) of was read from `read_cmd_fd` into `buf`
 uint32_t input_read(char *buf, uint32_t count)
 {
+  if (embedded_mode) {
+    return 0;
+  }
+
   return rstream_read(read_stream, buf, count);
 }
 
@@ -129,6 +146,11 @@ bool os_isatty(int fd)
 
 static bool input_poll(int32_t ms)
 {
+  if (embedded_mode) {
+    EventSource input_sources[] = { signal_event_source(), NULL };
+    return event_poll(ms, input_sources);
+  }
+
   EventSource input_sources[] = {
     rstream_event_source(read_stream),
     NULL
diff --git a/src/nvim/os/signal.c b/src/nvim/os/signal.c
index 17f270a5cc..2f93cfb08a 100644
--- a/src/nvim/os/signal.c
+++ b/src/nvim/os/signal.c
@@ -39,7 +39,10 @@ void signal_init(void)
   uv_signal_start(&shup, signal_cb, SIGHUP);
   uv_signal_start(&squit, signal_cb, SIGQUIT);
   uv_signal_start(&sterm, signal_cb, SIGTERM);
-  uv_signal_start(&swinch, signal_cb, SIGWINCH);
+  if (!embedded_mode) {
+    // TODO(tarruda): There must be an API function for resizing window
+    uv_signal_start(&swinch, signal_cb, SIGWINCH);
+  }
 #ifdef SIGPWR
   uv_signal_init(uv_default_loop(), &spwr);
   uv_signal_start(&spwr, signal_cb, SIGPWR);
diff --git a/src/nvim/os/wstream.c b/src/nvim/os/wstream.c
index 194bf757e4..44463c7c88 100644
--- a/src/nvim/os/wstream.c
+++ b/src/nvim/os/wstream.c
@@ -1,6 +1,7 @@
 #include <assert.h>
 #include <stdint.h>
 #include <stdbool.h>
+#include <stdlib.h>
 
 #include <uv.h>
 
@@ -20,7 +21,7 @@ struct wstream {
   size_t maxmem;
   // Number of pending requests
   size_t pending_reqs;
-  bool freed;
+  bool freed, free_handle;
   // (optional) Write callback and data
   wstream_cb cb;
   void *data;
@@ -60,6 +61,7 @@ WStream * wstream_new(size_t maxmem)
   rv->curmem = 0;
   rv->pending_reqs = 0;
   rv->freed = false;
+  rv->free_handle = false;
   rv->cb = NULL;
 
   return rv;
@@ -68,9 +70,13 @@ WStream * wstream_new(size_t maxmem)
 /// Frees all memory allocated for a WStream instance
 ///
 /// @param wstream The `WStream` instance
-void wstream_free(WStream *wstream)
-{
+void wstream_free(WStream *wstream) {
   if (!wstream->pending_reqs) {
+    handle_set_wstream((uv_handle_t *)wstream->stream, NULL);
+    if (wstream->free_handle) {
+      uv_close((uv_handle_t *)wstream->stream, close_cb);
+    }
+
     free(wstream);
   } else {
     wstream->freed = true;
@@ -87,6 +93,24 @@ void wstream_set_stream(WStream *wstream, uv_stream_t *stream)
   wstream->stream = stream;
 }
 
+/// Sets the underlying file descriptor that will be written to. Only pipes
+/// are supported for now.
+///
+/// @param wstream The `WStream` instance
+/// @param file The file descriptor
+void wstream_set_file(WStream *wstream, uv_file file)
+{
+  uv_handle_type type = uv_guess_handle(file);
+
+  assert(type == UV_NAMED_PIPE || type == UV_TTY);
+  wstream->stream = xmalloc(sizeof(uv_pipe_t));
+  uv_pipe_init(uv_default_loop(), (uv_pipe_t *)wstream->stream, 0);
+  uv_pipe_open((uv_pipe_t *)wstream->stream, file);
+  wstream->stream->data = NULL;
+  handle_set_wstream((uv_handle_t *)wstream->stream, wstream);
+  wstream->free_handle = true;
+}
+
 /// Sets a callback that will be called on completion of a write request,
 /// indicating failure/success.
 ///
@@ -211,3 +235,16 @@ static void release_wbuffer(WBuffer *buffer)
     free(buffer);
   }
 }
+
+static void close_cb(uv_handle_t *handle)
+{
+  WStream *wstream = handle_get_wstream(handle);
+
+  if (wstream) {
+    free(wstream);
+  }
+
+  free(handle->data);
+  free(handle);
+}
+
diff --git a/src/nvim/os_unix.c b/src/nvim/os_unix.c
index af17676ebf..1b092c8261 100644
--- a/src/nvim/os_unix.c
+++ b/src/nvim/os_unix.c
@@ -88,6 +88,18 @@ static int did_set_icon = FALSE;
  */
 void mch_write(char_u *s, int len)
 {
+  if (embedded_mode) {
+    // TODO(tarruda): This is a temporary hack to stop Neovim from writing
+    // messages to stdout in embedded mode. In the future, embedded mode will
+    // be the only possibility(GUIs will always start neovim with a msgpack-rpc
+    // over stdio) and this function won't exist.
+    //
+    // The reason for this is because before Neovim fully migrates to a
+    // msgpack-rpc-driven architecture, we must have a fully functional
+    // UI working
+    return;
+  }
+
   ignored = (int)write(1, (char *)s, len);
   if (p_wd)             /* Unix is too fast, slow down a bit more */
     os_microdelay(p_wd, false);
diff --git a/src/nvim/term.c b/src/nvim/term.c
index 36e433d624..d2c524e2e8 100644
--- a/src/nvim/term.c
+++ b/src/nvim/term.c
@@ -2360,6 +2360,9 @@ void set_shellsize(int width, int height, int mustset)
  */
 void settmode(int tmode)
 {
+  if (embedded_mode) {
+    return;
+  }
 
   if (full_screen) {
     /*