#517 Implement some LSP message handling

2 files changed, 158 insertions, 0 deletions

diff --git a/autoload/ale/lsp.vim b/autoload/ale/lsp.vim
new file mode 100644
index 00000000..e01e4eb6
--- /dev/null
+++ b/autoload/ale/lsp.vim
@@ -0,0 +1,93 @@
+" Author: w0rp <devw0rp@gmail.com>
+" Description: Language Server Protocol client code
+
+let g:ale_lsp_next_message_id = 1
+
+function! ale#lsp#GetNextMessageID() abort
+    " Use the current ID
+    let l:id = g:ale_lsp_next_message_id
+
+    " Increment the ID variable.
+    let g:ale_lsp_next_message_id += 1
+
+    " When the ID overflows, reset it to 1. By the time we hit the initial ID
+    " again, the messages will be long gone.
+    if g:ale_lsp_next_message_id < 1
+        let g:ale_lsp_next_message_id = 1
+    endif
+
+    return l:id
+endfunction
+
+" (method_name, params)
+function! ale#lsp#CreateMessage(method_name, ...) abort
+    if a:0 > 1
+        throw 'Too many arguments!'
+    endif
+
+    let l:obj = {
+    \   'id': ale#lsp#GetNextMessageID(),
+    \   'jsonrpc': '2.0',
+    \   'method': a:method_name,
+    \}
+
+    if a:0 > 0
+        let l:obj.params = a:1
+    endif
+
+    let l:body = json_encode(l:obj)
+
+    return 'Content-Length: ' . strlen(l:body) . "\r\n\r\n" . l:body
+endfunction
+
+function! ale#lsp#ReadMessage(data) abort
+    let l:header_end_index = match(a:data, "\r\n\r\n")
+
+    if l:header_end_index < 0
+        throw 'Invalid messaage: ' . string(a:data)
+    endif
+
+    return json_decode(a:data[l:header_end_index + 4:])
+endfunction
+
+" Constants for message severity codes.
+let s:SEVERITY_ERROR = 1
+let s:SEVERITY_WARNING = 2
+let s:SEVERITY_INFORMATION = 3
+let s:SEVERITY_HINT = 4
+
+" Parse the message for textDocument/publishDiagnostics
+function! ale#lsp#ReadDiagnostics(params) abort
+    let l:filename = a:params.uri
+    let l:loclist = []
+
+    for l:diagnostic in a:params.diagnostics
+        let l:severity = get(l:diagnostic, 'severity', 0)
+        let l:loclist_item = {
+        \   'message': l:diagnostic.message,
+        \   'type': 'E',
+        \   'lnum': l:diagnostic.range.start.line + 1,
+        \   'col': l:diagnostic.range.start.character + 1,
+        \   'end_lnum': l:diagnostic.range.end.line + 1,
+        \   'end_col': l:diagnostic.range.end.character + 1,
+        \}
+
+        if l:severity == s:SEVERITY_WARNING
+            let l:loclist_item.type = 'W'
+        elseif l:severity == s:SEVERITY_INFORMATION
+            " TODO: Use 'I' here in future.
+            let l:loclist_item.type = 'W'
+        elseif l:severity == s:SEVERITY_HINT
+            " TODO: Use 'H' here in future
+            let l:loclist_item.type = 'W'
+        endif
+
+        if has_key(l:diagnostic, 'code')
+            let l:loclist_item.nr = l:diagnostic.code
+        endif
+
+        call add(l:loclist, l:loclist_item)
+    endfor
+
+    return [l:filename, l:loclist]
+endfunction
diff --git a/autoload/ale/lsp/message.vim b/autoload/ale/lsp/message.vim
new file mode 100644
index 00000000..d46e68ab
--- /dev/null
+++ b/autoload/ale/lsp/message.vim
@@ -0,0 +1,65 @@
+" Author: w0rp <devw0rp@gmail.com>
+" Description: Language Server Protocol message implementations
+
+function! ale#lsp#message#CancelRequest(id) abort
+    return ale#lsp#CreateMessage('$/cancelRequest', {'id': a:id})
+endfunction
+
+function! ale#lsp#message#Initialize(processId, rootUri) abort
+    " TODO: Define needed capabilities.
+    return ale#lsp#CreateMessage('initialize', {
+    \   'processId': a:processId,
+    \   'rootUri': a:rootUri,
+    \   'capabilities': {},
+    \})
+endfunction
+
+function! ale#lsp#message#Initialized() abort
+    return ale#lsp#CreateMessage('initialized')
+endfunction
+
+function! ale#lsp#message#Shutdown() abort
+    return ale#lsp#CreateMessage('shutdown')
+endfunction
+
+function! ale#lsp#message#Exit() abort
+    return ale#lsp#CreateMessage('exit')
+endfunction
+
+function! ale#lsp#message#DidOpen(uri, languageId, version, text) abort
+    return ale#lsp#CreateMessage('textDocument/didOpen', {
+    \   'textDocument': {
+    \       'uri': a:uri,
+    \       'languageId': a:languageId,
+    \       'version': a:version,
+    \       'text': a:text,
+    \   },
+    \})
+endfunction
+
+function! ale#lsp#message#DidChange(uri, version, text) abort
+    " For changes, we simply send the full text of the document to the server.
+    return ale#lsp#CreateMessage('textDocument/didChange', {
+    \   'textDocument': {
+    \       'uri': a:uri,
+    \       'version': a:version,
+    \   },
+    \   'contentChanges': [{'text': a:text}]
+    \})
+endfunction
+
+function! ale#lsp#message#DidSave(uri) abort
+    return ale#lsp#CreateMessage('textDocument/didSave', {
+    \   'textDocument': {
+    \       'uri': a:uri,
+    \   },
+    \})
+endfunction
+
+function! ale#lsp#message#DidClose(uri) abort
+    return ale#lsp#CreateMessage('textDocument/didClose', {
+    \   'textDocument': {
+    \       'uri': a:uri,
+    \   },
+    \})
+endfunction