Add a basic language server

gtkblueprinttool/lsp.py

@@ -0,0 +1,159 @@
+# lsp.py
+#
+# Copyright 2021 James Westman <james@jwestman.net>
+#
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 3 of the
+# License, or (at your option) any later version.
+#
+# This file 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# SPDX-License-Identifier: LGPL-3.0-or-later
+
+
+import json, sys
+
+from .errors import PrintableError, CompileError, MultipleErrors
+from .lsp_enums import *
+from . import tokenizer, parser, utils
+
+
+def command(json_method):
+    def decorator(func):
+        func._json_method = json_method
+        return func
+    return decorator
+
+
+class LanguageServer:
+    commands = {}
+
+    def __init__(self):
+        self.client_capabilities = {}
+        self._open_files = {}
+
+    def run(self):
+        try:
+            while True:
+                line = ""
+                content_len = -1
+                while content_len == -1 or (line != "\n" and line != "\r\n"):
+                    line = sys.stdin.readline()
+                    if line == "":
+                        return
+                    if line.startswith("Content-Length:"):
+                        content_len = int(line.split("Content-Length:")[1].strip())
+                line = sys.stdin.read(content_len)
+                self._log("input: " + line)
+
+                data = json.loads(line)
+                method = data.get("method")
+                id = data.get("id")
+                params = data.get("params")
+
+                if method in self.commands:
+                    self.commands[method](self, id, params)
+        except Exception as e:
+            self._log(e)
+
+
+    def _send(self, data):
+        data["jsonrpc"] = "2.0"
+        line = json.dumps(data, separators=(",", ":")) + "\r\n"
+        self._log("output: " + line)
+        sys.stdout.write(f"Content-Length: {len(line)}\r\nContent-Type: application/vscode-jsonrpc; charset=utf-8\r\n\r\n{line}")
+        sys.stdout.flush()
+
+    def _log(self, msg):
+        pass
+
+    def _send_response(self, id, result):
+        self._send({
+            "id": id,
+            "result": result,
+        })
+
+    def _send_notification(self, method, params):
+        self._send({
+            "method": method,
+            "params": params,
+        })
+
+
+    @command("initialize")
+    def initialize(self, id, params):
+        self.client_capabilities = params.get("capabilities")
+        self._send_response(id, {
+            "capabilities": {
+                "textDocumentSync": {
+                    "openClose": True,
+                    "change": 1
+                }
+            }
+        })
+
+    @command("textDocument/didOpen")
+    def didOpen(self, id, params):
+        doc = params.get("textDocument")
+        uri = doc.get("uri")
+        version = doc.get("version")
+        text = doc.get("text")
+
+        self._open_files[uri] = text
+        self._send_diagnostics(uri)
+
+    @command("textDocument/didChange")
+    def didChange(self, id, params):
+        text = self._open_files[params.textDocument.uri]
+
+        for change in params.contentChanges:
+            start = utils.pos_to_idx(change.range.start.line, change.range.start.character, text)
+            end = utils.pos_to_idx(change.range.end.line, change.range.end.character, text)
+            text = text[:start] + change.text + text[end:]
+
+        self._open_files[params.textDocument.uri] = text
+        self._send_diagnostics(uri)
+
+    def _send_diagnostics(self, uri):
+        text = self._open_files[uri]
+
+        diagnostics = []
+        try:
+            tokens = tokenizer.tokenize(text)
+            ast = parser.parse(tokens)
+            diagnostics = [self._create_diagnostic(text, err) for err in list(ast.errors)]
+        except MultipleErrors as e:
+            diagnostics += [self._create_diagnostic(text, err) for err in e.errors]
+        except CompileError as e:
+            diagnostics += [self._create_diagnostic(text, e)]
+
+        self._send_notification("textDocument/publishDiagnostics", {
+            "uri": uri,
+            "diagnostics": diagnostics,
+        })
+
+    def _create_diagnostic(self, text, err):
+        start_l, start_c = utils.idx_to_pos(err.start, text)
+        end_l, end_c = utils.idx_to_pos(err.end or err.start, text)
+        return {
+            "range": {
+                "start": { "line": start_l - 1, "character": start_c },
+                "end": { "line": end_l - 1, "character": end_c },
+            },
+            "message": err.message,
+            "severity": 1,
+        }
+
+
+for name in dir(LanguageServer):
+    item = getattr(LanguageServer, name)
+    if callable(item) and hasattr(item, "_json_method"):
+        LanguageServer.commands[item._json_method] = item
+