Implement LSP symbol search

autoload/ale/lsp.vim

@@ -41,6 +41,7 @@ function! ale#lsp#Register(executable_or_address, project, init_options) abort
         \       'completion': 0,
         \       'completion_trigger_characters': [],
         \       'definition': 0,
+        \       'symbol_search': 0,
         \   },
         \}
     endif
@@ -203,6 +204,10 @@ function! s:UpdateCapabilities(conn, capabilities) abort
     if get(a:capabilities, 'definitionProvider') is v:true
         let a:conn.capabilities.definition = 1
     endif
+
+    if get(a:capabilities, 'workspaceSymbolProvider') is v:true
+        let a:conn.capabilities.symbol_search = 1
+    endif
 endfunction
 
 function! ale#lsp#HandleInitResponse(conn, response) abort
@@ -285,6 +290,7 @@ function! ale#lsp#MarkConnectionAsTsserver(conn_id) abort
     let l:conn.capabilities.completion = 1
     let l:conn.capabilities.completion_trigger_characters = ['.']
     let l:conn.capabilities.definition = 1
+    let l:conn.capabilities.symbol_search = 1
 endfunction
 
 " Start a program for LSP servers.

autoload/ale/lsp/message.vim

@@ -130,6 +130,12 @@ function! ale#lsp#message#References(buffer, line, column) abort
     \}]
 endfunction
 
+function! ale#lsp#message#Symbol(query) abort
+    return [0, 'workspace/symbol', {
+    \   'query': a:query,
+    \}]
+endfunction
+
 function! ale#lsp#message#Hover(buffer, line, column) abort
     return [0, 'textDocument/hover', {
     \   'textDocument': {

autoload/ale/preview.vim

@@ -46,11 +46,14 @@ function! ale#preview#ShowSelection(item_list) abort
 
     " Create lines to display to users.
     for l:item in a:item_list
+        let l:match = get(l:item, 'match', '')
+
         call add(
         \   l:lines,
         \   l:item.filename
         \       . ':' . l:item.line
-        \       . ':' . l:item.column,
+        \       . ':' . l:item.column
+        \       . (!empty(l:match) ? ' ' . l:match : ''),
         \)
     endfor
 

autoload/ale/symbol.vim

@@ -0,0 +1,109 @@
+let s:symbol_map = {}
+
+" Used to get the symbol map in tests.
+function! ale#symbol#GetMap() abort
+    return deepcopy(s:symbol_map)
+endfunction
+
+" Used to set the symbol map in tests.
+function! ale#symbol#SetMap(map) abort
+    let s:symbol_map = a:map
+endfunction
+
+function! ale#symbol#ClearLSPData() abort
+    let s:symbol_map = {}
+endfunction
+
+function! ale#symbol#HandleLSPResponse(conn_id, response) abort
+    if has_key(a:response, 'id')
+    \&& has_key(s:symbol_map, a:response.id)
+        let l:options = remove(s:symbol_map, a:response.id)
+
+        let l:result = get(a:response, 'result', v:null)
+        let l:item_list = []
+
+        if type(l:result) is v:t_list
+            " Each item looks like this:
+            " {
+            "   'name': 'foo',
+            "   'kind': 123,
+            "   'deprecated': v:false,
+            "   'location': {
+            "     'uri': 'file://...',
+            "     'range': {
+            "       'start': {'line': 0, 'character': 0},
+            "       'end': {'line': 0, 'character': 0},
+            "     },
+            "   },
+            "   'containerName': 'SomeContainer',
+            " }
+            for l:response_item in l:result
+                let l:location = l:response_item.location
+
+                call add(l:item_list, {
+                \ 'filename': ale#path#FromURI(l:location.uri),
+                \ 'line': l:location.range.start.line + 1,
+                \ 'column': l:location.range.start.character + 1,
+                \ 'match': l:response_item.name,
+                \})
+            endfor
+        endif
+
+        if empty(l:item_list)
+            call ale#util#Execute('echom ''No symbols found.''')
+        else
+            call ale#preview#ShowSelection(l:item_list)
+        endif
+    endif
+endfunction
+
+function! s:OnReady(linter, lsp_details, query, ...) abort
+    let l:buffer = a:lsp_details.buffer
+
+    " If we already made a request, stop here.
+    if getbufvar(l:buffer, 'ale_symbol_request_made', 0)
+        return
+    endif
+
+    let l:id = a:lsp_details.connection_id
+
+    let l:Callback = function('ale#symbol#HandleLSPResponse')
+    call ale#lsp#RegisterCallback(l:id, l:Callback)
+
+    let l:message = ale#lsp#message#Symbol(a:query)
+    let l:request_id = ale#lsp#Send(l:id, l:message)
+
+    call setbufvar(l:buffer, 'ale_symbol_request_made', 1)
+    let s:symbol_map[l:request_id] = {
+    \   'buffer': l:buffer,
+    \}
+endfunction
+
+function! s:Search(linter, buffer, query) abort
+    let l:lsp_details = ale#lsp_linter#StartLSP(a:buffer, a:linter)
+
+    if !empty(l:lsp_details)
+        call ale#lsp#WaitForCapability(
+        \   l:lsp_details.connection_id,
+        \   'symbol_search',
+        \   function('s:OnReady', [a:linter, l:lsp_details, a:query]),
+        \)
+    endif
+endfunction
+
+function! ale#symbol#Search(query) abort
+    if type(a:query) isnot v:t_string || empty(a:query)
+        throw 'A non-empty string must be provided!'
+    endif
+
+    let l:buffer = bufnr('')
+
+    " Set a flag so we only make one request.
+    call setbufvar(l:buffer, 'ale_symbol_request_made', 0)
+
+    for l:linter in ale#linter#Get(getbufvar(l:buffer, '&filetype'))
+        if !empty(l:linter.lsp) && l:linter.lsp isnot# 'tsserver'
+            call s:Search(l:linter, l:buffer, a:query)
+        endif
+    endfor
+endfunction