fix(clice): add commands, sync with upstream #4547

Problem:
The clice config is a copy of clangd's. Its root markers include files
clice does not read (compile_flags.txt, configure.ac) or that often sit
in subdirectories (.clang-tidy, .clang-format), which makes such a
subdirectory the workspace folder. It sends clangd's offsetEncoding and
editsNearCursor, which clice ignores. It lacks the cuda filetype, and
clice's compilation context requests are unreachable.

Solution:
- root_markers: clice.toml, compile_commands.json, .git.
- Drop the clangd capabilities; clice answers in UTF-16.
- Add the cuda filetype.
- Add :LspCliceShowContext, :LspCliceSwitchContext,
  :LspCliceResetContext and :LspCliceSwitchConfiguration.

1 files changed, 172 insertions, 18 deletions

diff --git a/lsp/clice.lua b/lsp/clice.lua
index d5ac4a50..023f4af5 100644
--- a/lsp/clice.lua
+++ b/lsp/clice.lua
@@ -2,26 +2,180 @@
 ---
 --- https://github.com/clice-io/clice
 --- Clice is a next-generation language server for modern C++, focused on performance and code intelligence
+---
+--- Commands:
+--- - `:LspCliceShowContext`, `:LspCliceSwitchContext`, `:LspCliceResetContext`: show, choose or
+---   reset the compilation context of the buffer: the source file a header compiles in, or the
+---   compile command of a source file listed with several.
+--- - `:LspCliceSwitchConfiguration`: select the build configuration (the `configuration` tags of
+---   the `clice.toml` rules) clice runs from its next start.
+
+---@param client vim.lsp.Client
+---@param bufnr integer
+---@param method string
+---@param params table
+---@param on_result fun(result: any)
+local function request(client, bufnr, method, params, on_result)
+  local sent = client:request(method, params, function(err, result)
+    if err then
+      vim.notify(('%s: %s'):format(method, err.message), vim.log.levels.ERROR)
+    else
+      on_result(result)
+    end
+  end, bufnr)
+  if not sent then
+    vim.notify(('%s: clice is not running'):format(method), vim.log.levels.ERROR)
+  end
+end
+
+--- Every page of the buffer's contexts, all from one listing epoch.
+---@param client vim.lsp.Client
+---@param bufnr integer
+---@param on_contexts fun(contexts: table[], epoch: integer)
+local function query_contexts(client, bufnr, on_contexts)
+  local uri = vim.uri_from_bufnr(bufnr)
+  local contexts, epoch = {}, nil
+  local function fetch()
+    request(client, bufnr, 'clice/queryContext', { uri = uri, offset = #contexts }, function(page)
+      if epoch and page.epoch ~= epoch then
+        contexts, epoch = {}, nil
+        return fetch()
+      end
+      epoch = page.epoch
+      vim.list_extend(contexts, page.contexts)
+      if #page.contexts > 0 and #contexts < page.total then
+        fetch()
+      else
+        on_contexts(contexts, epoch)
+      end
+    end)
+  end
+  fetch()
+end
+
+---@param client vim.lsp.Client
+---@param bufnr integer
+local function show_context(client, bufnr)
+  request(client, bufnr, 'clice/currentContext', { uri = vim.uri_from_bufnr(bufnr) }, function(current)
+    local context = current.context
+    if context == nil or context == vim.NIL then
+      return vim.notify('clice: no compilation context for this file')
+    end
+    local chosen = current.automatic and 'picked automatically' or 'chosen'
+    vim.notify(('clice: %s, %s (%s)'):format(context.label, context.description, chosen))
+  end)
+end
+
+---@param client vim.lsp.Client
+---@param bufnr integer
+local function reset_context(client, bufnr)
+  request(client, bufnr, 'clice/resetContext', { uri = vim.uri_from_bufnr(bufnr) }, function() end)
+end
+
+---@param client vim.lsp.Client
+---@param bufnr integer
+local function switch_context(client, bufnr)
+  local uri = vim.uri_from_bufnr(bufnr)
+  query_contexts(client, bufnr, function(contexts, epoch)
+    request(client, bufnr, 'clice/currentContext', { uri = uri }, function(current)
+      if current.epoch ~= epoch then
+        return switch_context(client, bufnr)
+      elseif #contexts == 0 then
+        return vim.notify('clice: no compilation contexts for this file')
+      end
+      local active = current.context ~= vim.NIL and current.context or {}
+      if not current.automatic then
+        table.insert(contexts, 1, { automatic = true })
+      end
+      vim.ui.select(contexts, {
+        prompt = 'Compilation context',
+        format_item = function(item)
+          if item.automatic then
+            return 'Automatic'
+          end
+          local same = item.uri == active.uri
+            and item.occurrence == active.occurrence
+            and item.commandHash == active.commandHash
+          return ('%s  %s%s'):format(item.label, item.description, same and ' (in use)' or '')
+        end,
+      }, function(choice)
+        if not choice then
+          return
+        elseif choice.automatic then
+          return reset_context(client, bufnr)
+        end
+        request(client, bufnr, 'clice/switchContext', {
+          uri = uri,
+          contextUri = choice.uri,
+          occurrence = choice.occurrence,
+          commandHash = choice.commandHash,
+          epoch = epoch,
+        }, function(result)
+          if result.stale then
+            vim.notify('clice: the contexts changed meanwhile, pick again', vim.log.levels.WARN)
+          elseif not result.success then
+            vim.notify('clice: failed to switch the compilation context', vim.log.levels.WARN)
+          end
+        end)
+      end)
+    end)
+  end)
+end
+
+---@param client vim.lsp.Client
+---@param bufnr integer
+local function switch_configuration(client, bufnr)
+  local uri = vim.uri_from_bufnr(bufnr)
+  request(client, bufnr, 'clice/listConfigurations', { uri = uri }, function(list)
+    if #list.configurations == 0 then
+      return vim.notify('clice: the rules declare no build configurations')
+    end
+    vim.ui.select(list.configurations, {
+      prompt = 'Build configuration',
+      format_item = function(name)
+        local notes = {}
+        if name == list.active then
+          table.insert(notes, 'active')
+        elseif name == list.selected then
+          table.insert(notes, 'selected for the next start')
+        end
+        if name == list.defaultConfiguration then
+          table.insert(notes, 'default')
+        end
+        return #notes == 0 and name or ('%s (%s)'):format(name, table.concat(notes, ', '))
+      end,
+    }, function(name)
+      if not name then
+        return
+      end
+      request(client, bufnr, 'clice/switchConfiguration', { name = name, uri = uri }, function(result)
+        if not result.success then
+          vim.notify('clice: failed to switch the build configuration', vim.log.levels.WARN)
+        elseif name ~= list.active then
+          vim.notify(('clice: %s applies once clice restarts'):format(name))
+        end
+      end)
+    end)
+  end)
+end
 
 ---@type vim.lsp.Config
 return {
   cmd = { 'clice', 'serve' },
-  filetypes = { 'c', 'cpp' },
-  root_markers = {
-    'clice.toml',
-    '.clang-tidy',
-    '.clang-format',
-    'compile_commands.json',
-    'compile_flags.txt',
-    'configure.ac',
-    '.git',
-  },
-  capabilities = {
-    textDocument = {
-      completion = {
-        editsNearCursor = true,
-      },
-    },
-    offsetEncoding = { 'utf-8' },
-  },
+  filetypes = { 'c', 'cpp', 'cuda' },
+  root_markers = { 'clice.toml', 'compile_commands.json', '.git' },
+  on_attach = function(client, bufnr)
+    vim.api.nvim_buf_create_user_command(bufnr, 'LspCliceShowContext', function()
+      show_context(client, bufnr)
+    end, { desc = 'Show the compilation context in use' })
+    vim.api.nvim_buf_create_user_command(bufnr, 'LspCliceSwitchContext', function()
+      switch_context(client, bufnr)
+    end, { desc = 'Switch the compilation context' })
+    vim.api.nvim_buf_create_user_command(bufnr, 'LspCliceResetContext', function()
+      reset_context(client, bufnr)
+    end, { desc = 'Use the automatic compilation context' })
+    vim.api.nvim_buf_create_user_command(bufnr, 'LspCliceSwitchConfiguration', function()
+      switch_configuration(client, bufnr)
+    end, { desc = 'Switch the build configuration' })
+  end,
 }