support lookups via language servers (LSP)HEADmaster-fmsbw-cimaster

* The main interface is the `FT` command.
  `FT` was an undocumented Video TECO command for etags/ctags lookups.
  I don't want to exactly copy its interface, though.
* `FT` allows looking up symbol names,
  definitions and references.
* ctags will be supported via ctags-lsp.
  LSP support is more powerful though and works without
  regenerating TAGS files all the time.
  The LSP will also allow you to customize auto-completions
  using SciTECO itself (i.e. by writing a language server
  in SciTECO).
* For multiple results, `FT$` can be used to cycle through
  results - this should mimic repeated `S$` or `N$`.
* `:FT...$` does a fuzzy search. IMHO it's not important
  to return a status integer instead. `FT` will only
  really be used in interactive mode.
* Document synchronization is supported via hooks from
  ring.c and via Scintilla notifications.
* Currently, the LSP communication is based on blocking
  GIOChannels. This means that a misbehaving hanging
  server could "lock up" the entire editor (FIXME).
  Only on ncurses you can always kill the subprocess by
  pressing CTRL+C.
  We need helper functions in spawn.c to read and write
  with interruptions.
* The textDocument/didChange notification transmits
  not only all edits, but all files' contents as well
  during initial synchronization.
  Therefore it is optimized to write and JSON-escape
  data without copying them around in memory and without
  destroying the buffer gap.
* Use $SCITECO_LSP to configure the language server.
  You can also use `tee` to capture stdin and stdout.
  Perhaps $SCITECO_LSP should be saved in .teco_session,
  so you can change it between projects?
* $SCITECO_LSP_ROOT is used to point to the project's
  root directory. session.tes will set it up automatically.

1 files changed, 38 insertions, 3 deletions

diff --git a/src/ring.c b/src/ring.c
index cda15c4..dc43ac5 100644
--- a/src/ring.c
+++ b/src/ring.c
@@ -37,6 +37,7 @@
 #include "glob.h"
 #include "error.h"
 #include "list.h"
+#include "lsp.h"
 #include "ring.h"
 
 /** @private @static @memberof teco_buffer_t */
@@ -79,13 +80,20 @@ teco_buffer_undo_edit(teco_buffer_t *ctx)
 static gboolean
 teco_buffer_load(teco_buffer_t *ctx, const gchar *filename, GError **error)
 {
+	teco_buffer_set_filename(ctx, filename);
+
+	if (!teco_lsp_didopen(ctx, error))
+		return FALSE;
+
+	/*
+	 * Will also call teco_lsp_didchange_insert() following
+	 * Scintilla notifications.
+	 */
 	if (!teco_view_load(ctx->view, filename, TRUE, error))
 		return FALSE;
 
 	/* currently buffer cannot be dirty */
 	g_assert(ctx->state == TECO_BUFFER_CLEAN);
-
-	teco_buffer_set_filename(ctx, filename);
 	return TRUE;
 }
 
@@ -93,7 +101,9 @@ teco_buffer_load(teco_buffer_t *ctx, const gchar *filename, GError **error)
 static gboolean
 teco_buffer_save(teco_buffer_t *ctx, const gchar *filename, GError **error)
 {
-	if (!filename && !ctx->filename) {
+	gboolean is_unnamed = !ctx->filename;
+
+	if (!filename && is_unnamed) {
 		g_set_error_literal(error, TECO_ERROR, TECO_ERROR_FAILED,
 		                    "Cannot save the unnamed file "
 		                    "without providing a file name");
@@ -127,6 +137,13 @@ teco_buffer_save(teco_buffer_t *ctx, const gchar *filename, GError **error)
 	teco_undo_cstring(ctx->filename);
 	teco_buffer_set_filename(ctx, filename ? : ctx->filename);
 
+	/*
+	 * Unnamed buffers were not synced with the LSP server,
+	 * so we do this now.
+	 */
+	if (is_unnamed && !teco_lsp_sync(ctx, error))
+		return FALSE;
+
 	return TRUE;
 }
 
@@ -400,6 +417,9 @@ teco_ring_edit_by_name(const gchar *filename, GError **error)
 		else
 			teco_interface_msg(TECO_MSG_INFO,
 			                   "Added new unnamed file to ring.");
+
+		if (!teco_lsp_didopen(buffer, error))
+			return FALSE;
 	}
 
 	return teco_ed_hook(TECO_ED_HOOK_ADD, error);
@@ -467,6 +487,9 @@ teco_ring_close(teco_buffer_t *buffer, GError **error)
 		teco_ring_remove_buffer(buffer);
 	}
 
+	if (!teco_lsp_didclose(buffer, error))
+		return FALSE;
+
 	/* transfer responsibility to the undo token object */
 	teco_undo_ring_reinsert(buffer);
 
@@ -489,6 +512,18 @@ teco_ring_set_scintilla_undo(gboolean state)
 	}
 }
 
+gboolean
+teco_ring_sync_lsp(GError **error)
+{
+	for (teco_tailq_entry_t *cur = teco_ring_head.first; cur != NULL; cur = cur->next) {
+		teco_buffer_t *buffer = (teco_buffer_t *)cur;
+		if (buffer->filename && !teco_lsp_sync(buffer, error))
+			return FALSE;
+	}
+
+	return TRUE;
+}
+
 void
 teco_ring_cleanup(void)
 {