1 files changed, 68 insertions, 0 deletions
diff --git a/lua/blink/cmp/sources/lib/queue.lua b/lua/blink/cmp/sources/lib/queue.lua
new file mode 100644
index 0000000..3947902
--- /dev/null
+++ b/lua/blink/cmp/sources/lib/queue.lua
@@ -0,0 +1,68 @@
+local async = require('blink.cmp.lib.async')
+
+--- @class blink.cmp.SourcesQueue
+--- @field id number
+--- @field providers table<string, blink.cmp.SourceProvider>
+--- @field request blink.cmp.Task | nil
+--- @field queued_request_context blink.cmp.Context | nil
+--- @field cached_items_by_provider table<string, blink.cmp.CompletionResponse> | nil
+--- @field on_completions_callback fun(context: blink.cmp.Context, responses: table<string, blink.cmp.CompletionResponse>)
+---
+--- @field new fun(context: blink.cmp.Context, providers: table<string, blink.cmp.SourceProvider>, on_completions_callback: fun(context: blink.cmp.Context, responses: table<string, blink.cmp.CompletionResponse>)): blink.cmp.SourcesQueue
+--- @field get_cached_completions fun(self: blink.cmp.SourcesQueue): table<string, blink.cmp.CompletionResponse> | nil
+--- @field get_completions fun(self: blink.cmp.SourcesQueue, context: blink.cmp.Context)
+--- @field destroy fun(self: blink.cmp.SourcesQueue)
+
+--- @type blink.cmp.SourcesQueue
+--- @diagnostic disable-next-line: missing-fields
+local queue = {}
+
+function queue.new(context, providers, on_completions_callback)
+  local self = setmetatable({}, { __index = queue })
+  self.id = context.id
+  self.providers = providers
+
+  self.request = nil
+  self.queued_request_context = nil
+  self.on_completions_callback = on_completions_callback
+
+  return self
+end
+
+function queue:get_cached_completions() return self.cached_items_by_provider end
+
+function queue:get_completions(context)
+  assert(context.id == self.id, 'Requested completions on a sources context with a different context ID')
+
+  if self.request ~= nil then
+    if self.request.status == async.STATUS.RUNNING then
+      self.queued_request_context = context
+      return
+    else
+      self.request:cancel()
+    end
+  end
+
+  -- Create a task to get the completions, send responses upstream
+  -- and run the queued request, if it exists
+  local tree = require('blink.cmp.sources.lib.tree').new(context, vim.tbl_values(self.providers))
+  self.request = tree:get_completions(context, function(items_by_provider)
+    self.cached_items_by_provider = items_by_provider
+    self.on_completions_callback(context, items_by_provider)
+
+    -- run the queued request, if it exists
+    local queued_context = self.queued_request_context
+    if queued_context ~= nil then
+      self.queued_request_context = nil
+      self.request:cancel()
+      self:get_completions(queued_context)
+    end
+  end)
+end
+
+function queue:destroy()
+  self.on_completions_callback = function() end
+  if self.request ~= nil then self.request:cancel() end
+end
+
+return queue