add new on_server_ready() API (#56)

7 files changed, 84 insertions, 17 deletions

diff --git a/CUSTOM_SERVERS.md b/CUSTOM_SERVERS.md
index 31938b48..f0d548d8 100644
--- a/CUSTOM_SERVERS.md
+++ b/CUSTOM_SERVERS.md
@@ -11,10 +11,11 @@ to the [Lua docs](./lua/nvim-lsp-installer/server.lua) for more details.
 Each `Server` instance must provide an `installer` property. This _must_ be a function with the signature `function (server, callback)`, where `server` is the server instance that is being installed, and `callback` is a function that
 _must_ be called upon completion (successful or not) by the installer implementation.
 
-Most likely, nvim-lsp-installer already have the installer implementations you'd need. You may find the available installers below.
-
 ## Core installers
 
+Most likely, nvim-lsp-installer already have the installer implementations you need. Below are all the currently
+available installers that are available out of the box.
+
 -   ### Go
 
     #### `go.packages(packages: table)`
@@ -36,7 +37,7 @@ Most likely, nvim-lsp-installer already have the installer implementations you'd
 
 -   ### npm
 
-    #### `npm3.packages(packages: table)`
+    #### `npm.packages(packages: table)`
 
     Returns an installer that installs the provided list of `packages`.
 
@@ -45,7 +46,7 @@ Most likely, nvim-lsp-installer already have the installer implementations you'd
     ```lua
     local npm = require "nvim-lsp-installer.installers.npm"
 
-    local installer = npm.packages { "graphql-language-service-cli", "graphql" },
+    local installer = npm.packages { "graphql-language-service-cli", "graphql" }
     ```
 
     #### `npm.executable(root_dir: string, executable: string)`
diff --git a/README.md b/README.md
index afa22ff9..40d68a1f 100644
--- a/README.md
+++ b/README.md
@@ -48,16 +48,14 @@ use {
 ### Setup
 
 ```lua
-local lsp_installer = require'nvim-lsp-installer'
+local lsp_installer = require("nvim-lsp-installer")
 
 function common_on_attach(client, bufnr)
-    -- setup buffer keymaps etc.
+    -- ... set up buffer keymaps, etc.
 end
 
-local installed_servers = lsp_installer.get_installed_servers()
-
-for _, server in pairs(installed_servers) do
-    opts = {
+lsp_installer.on_server_ready(function(server)
+    local opts = {
         on_attach = common_on_attach,
     }
 
@@ -67,7 +65,8 @@ for _, server in pairs(installed_servers) do
     -- end
 
     server:setup(opts)
-end
+    vim.cmd [[ do User LspAttachBuffers ]]
+end)
 ```
 
 For more advanced use cases you may also interact with more APIs nvim-lsp-installer has to offer, for example the following (refer to `:help nvim-lsp-installer` for more docs):
diff --git a/doc/nvim-lsp-installer.txt b/doc/nvim-lsp-installer.txt
index 80a004a3..7f4c68a3 100644
--- a/doc/nvim-lsp-installer.txt
+++ b/doc/nvim-lsp-installer.txt
@@ -29,14 +29,14 @@ Install a language server via `:LspInstall`, for example: >
 
 Then, somewhere in your initialization script (see `:h init.lua`): >
 
+    local lsp_installer = require("nvim-lsp-installer")
+
     function common_on_attach(client, bufnr)
-        -- .. set up keymaps, etc.
+        -- ... set up buffer keymaps, etc.
     end
 
-    local installed_servers = lsp_installer.get_installed_servers()
-
-    for _, server in pairs(installed_servers) do
-        opts = {
+    lsp_installer.on_server_ready(function(server)
+        local opts = {
             on_attach = common_on_attach,
         }
 
@@ -46,7 +46,8 @@ Then, somewhere in your initialization script (see `:h init.lua`): >
         -- end
 
         server:setup(opts)
-    end
+        vim.cmd [[ do User LspAttachBuffers ]]
+    end)
 <
 
 ==============================================================================
@@ -123,6 +124,30 @@ uninstall({server_name})
         Parameters: ~
             {server_name} (string) The server to uninstall.
 
+register({server})
+        Registers a {server} instance with nvim-lsp-installer.
+
+        {server} must be an instance of |lsp_installer.Server|.
+
+        Parameters: ~
+            {server} (|lsp_installer.Server|) The server to register.
+
+on_server_ready({cb})
+        Registers a callback to be executed each time a server is
+        ready to be initiated.
+
+        When called, all currently installed servers will be
+        considered ready to be initiated and will each
+        individually be invoked on {cb}.
+
+        Parameters: ~
+            {cb} (function) Function to be invoked when a server is ready to
+            be initiated.
+
+        Return: ~
+            Returns a function which when called will de-register the
+            cb} from any future dispatches.
+
 ==============================================================================
 Lua module: nvim-lsp-installer.server                  *lsp_installer.server*
 
diff --git a/lua/nvim-lsp-installer.lua b/lua/nvim-lsp-installer.lua
index eae7363e..881db323 100644
--- a/lua/nvim-lsp-installer.lua
+++ b/lua/nvim-lsp-installer.lua
@@ -1,4 +1,5 @@
 local notify = require "nvim-lsp-installer.notify"
+local dispatcher = require "nvim-lsp-installer.dispatcher"
 
 local M = {}
 
@@ -103,4 +104,20 @@ function M.register(server)
     _SERVERS[server.name] = server
 end
 
+function M.on_server_ready(cb)
+    dispatcher.register_server_ready_callback(cb)
+    for _, server in pairs(M.get_installed_servers()) do
+        dispatcher.dispatch_server_ready(server)
+    end
+end
+
+-- "Proxy" function for triggering attachment of LSP servers to all buffers (useful when just installed a new server
+-- that wasn't installed at launch)
+function M.lsp_attach_proxy()
+    -- As of writing, if the lspconfig server provides a filetypes setting, it uses FileType as trigger, otherwise it uses BufReadPost
+    local cur_bufnr = vim.fn.bufnr "%"
+    vim.cmd [[ bufdo do FileType | do BufReadPost ]]
+    vim.cmd(("buffer %s"):format(cur_bufnr)) -- restore buffer
+end
+
 return M
diff --git a/lua/nvim-lsp-installer/dispatcher.lua b/lua/nvim-lsp-installer/dispatcher.lua
new file mode 100644
index 00000000..c8ec34a7
--- /dev/null
+++ b/lua/nvim-lsp-installer/dispatcher.lua
@@ -0,0 +1,21 @@
+local M = {}
+
+local registered_callbacks = {}
+
+function M.dispatch_server_ready(server)
+    for _, callback in pairs(registered_callbacks) do
+        callback(server)
+    end
+end
+
+local idx = 0
+function M.register_server_ready_callback(callback)
+    local key = idx + 1
+    registered_callbacks[("%d"):format(key)] = callback
+    return function ()
+        table.remove(registered_callbacks, key)
+    end
+end
+
+
+return M
diff --git a/lua/nvim-lsp-installer/server.lua b/lua/nvim-lsp-installer/server.lua
index 8b72ce53..edc80253 100644
--- a/lua/nvim-lsp-installer/server.lua
+++ b/lua/nvim-lsp-installer/server.lua
@@ -1,4 +1,5 @@
 local notify = require "nvim-lsp-installer.notify"
+local dispatcher = require "nvim-lsp-installer.dispatcher"
 local fs = require "nvim-lsp-installer.fs"
 local path = require "nvim-lsp-installer.path"
 
@@ -83,6 +84,7 @@ function M.Server:install()
             pcall(self.uninstall, self)
         else
             notify(("Successfully installed %s."):format(self.name))
+            dispatcher.dispatch_server_ready(self)
         end
     end)
 end
diff --git a/plugin/nvim-lsp-installer.vim b/plugin/nvim-lsp-installer.vim
index a915207c..6e9e192d 100644
--- a/plugin/nvim-lsp-installer.vim
+++ b/plugin/nvim-lsp-installer.vim
@@ -40,5 +40,7 @@ command! -nargs=1 -complete=custom,s:LspUninstallCompletion LspUninstall exe s:L
 command! LspUninstallAll call s:LspUninstallAll()
 command! LspPrintInstalled call s:LspPrintInstalled()
 
+autocmd User LspAttachBuffers lua require"nvim-lsp-installer".lsp_attach_proxy()
+
 let &cpo = s:save_cpo
 unlet s:save_cpo