feat: Write types and helper functions for implementing LSP

internal/wire/lsp/lsp.go

@@ -0,0 +1,101 @@
+package lsp
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func ReadBuffer(reader *bufio.Reader) ([]byte, bool) {
+	var length int
+	for {
+		header, err := reader.ReadString('\n')
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error reading header: %v\n", err)
+			return nil, false
+		}
+		if header == "\r\n" {
+			break
+		}
+		// TODO: trim the remaining \r also
+		header = strings.TrimSpace(header)
+		switch {
+		case strings.HasPrefix(header, "Content-Length: "):
+			value := strings.TrimPrefix(header, "Content-Length: ")
+			length, err = strconv.Atoi(value)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Content-Length is not a valid integer: %v\n", err)
+				return nil, false
+			}
+		case strings.HasPrefix(header, "Content-Type: "):
+			value := strings.TrimPrefix(header, "Content-Type: ")
+			if value != "application/vscode-jsonrpc; charset=utf-8" {
+				fmt.Fprintf(os.Stderr, "Content-Type is invalid: %v\n", value)
+				return nil, false
+			}
+		default:
+			fmt.Fprintf(os.Stderr, "header field name is invalid: %v", header)
+			return nil, false
+		}
+	}
+	// Read len bytes of content
+	buf := make([]byte, length)
+	n, err := io.ReadFull(reader, buf)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error reading content %v\n", err)
+		return nil, false
+	}
+	if n != length {
+		fmt.Fprintln(os.Stderr, "Content-Length and content length do not match")
+		return nil, false
+	}
+	return buf, true
+}
+
+func ParseMessage(buf []byte) (map[string]interface{}, bool) {
+	in := make(map[string]interface{})
+	if err := json.Unmarshal(buf, &in); err != nil {
+		fmt.Fprintf(os.Stderr, "error deserializing request: %v\n", err)
+		return nil, false
+	}
+	return in, true
+}
+
+func ParseRequest(buf []byte, req interface{}) bool {
+	if err := json.Unmarshal(buf, req); err != nil {
+		fmt.Fprintf(os.Stderr, "Error parsing request: %v\n", err)
+		return false
+	}
+	return true
+}
+
+func StringifyResponse(res interface{}) bool {
+	bytes, err := json.Marshal(res)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error serializing response: %v\n", err)
+		return false
+	}
+	fmt.Printf("Content-Length: %d\r\n", len(bytes))
+	fmt.Printf("\r\n")
+	// TODO: \r\n at the end is redundant
+	fmt.Print(string(bytes) + "\r\n")
+	return true
+}
+
+// func calculatePos(fset *token.FileSet, path string, line int, char int) token.Pos {
+// 	var file *token.File
+// 	fset.Iterate(func(f *token.File) bool {
+// 		if f.Name() == path {
+// 			file = f
+// 			return false
+// 		}
+// 		return true
+// 	})
+// 	offset := int(file.LineStart(line)) - int(file.Base())
+// 	offset += char
+// 	return file.Pos(offset)
+// }

internal/wire/lsp/types.go

@@ -0,0 +1,80 @@
+package lsp
+
+type InitializeRequest struct {
+	Jsonrpc string           `json:"jsonrpc"`
+	Id      int              `json:"id"`
+	Method  string           `json:"method"`
+	Params  InitializeParams `json:"params"`
+}
+
+type InitializeParams struct {
+	Capabilities ClientCapabilities `json:"capabilities"`
+}
+
+type ClientCapabilities struct {
+	Workspace WorkspaceClientCapabilities `json:"workspace"`
+}
+
+type WorkspaceClientCapabilities struct {
+	Configuration    bool `json:"configuration"`
+	WorkspaceFolders bool `json:"workspaceFolders"`
+}
+
+type InitializeResponse struct {
+	Jsonrpc string           `json:"jsonrpc"`
+	Id      int              `json:"id"`
+	Result  InitializeResult `json:"result"`
+}
+type InitializeResult struct {
+	Capabilities ServerCapabilities `json:"capabilities"`
+}
+
+type ServerCapabilities struct {
+	TextDocumentSync int                         `json:"textDocumentSync"`
+	HoverProvider    bool                        `json:"hoverProvider"`
+	Workspace        WorkspaceServerCapabilities `json:"workspace"`
+}
+
+type WorkspaceServerCapabilities struct {
+	WorkspaceFolders WorkspaceFoldersServerCapabilities `json:"workspaceFolders"`
+}
+
+type WorkspaceFoldersServerCapabilities struct {
+	Supported bool `json:"supported"`
+}
+
+type HoverRequest struct {
+	Jsonrpc string      `json:"jsonrpc"`
+	Id      int         `json:"id"`
+	Method  string      `json:"method"`
+	Params  HoverParams `json:"Params"`
+}
+
+type HoverParams struct {
+	TextDocument TextDocumentIdentifier `json:"textDocument"`
+	Position     Position               `json:"position"`
+}
+
+type TextDocumentIdentifier struct {
+	Uri string `json:"uri"`
+}
+
+type Position struct {
+	Line      int `json:"line"`
+	Character int `json:"character"`
+}
+
+type HoverResponse struct {
+	Jsonrpc string      `json:"jsonrpc"`
+	Id      int         `json:"id"`
+	Result  HoverResult `json:"result"`
+}
+
+type HoverResult struct {
+	Contents MarkupContent `json:"contents"`
+}
+
+type MarkupContent struct {
+	Kind  string `json:"kind"`
+	Value string `json:"value"`
+}