Implement cursor presentation lease

1 files changed, 58 insertions, 0 deletions

diff --git a/lua/clever_f/feedback_service.lua b/lua/clever_f/feedback_service.lua
index b915f6a..a06f6d8 100644
--- a/lua/clever_f/feedback_service.lua
+++ b/lua/clever_f/feedback_service.lua
@@ -6,6 +6,8 @@ local M = {}
 local FeedbackService = {}
 FeedbackService.__index = FeedbackService
 M.FeedbackService = FeedbackService
+local CursorPresentationLease = {}
+M.CursorPresentationLease = CursorPresentationLease
 
 M.DEFAULT_LABEL_GROUP = "CleverFDefaultLabel"
 M.Priority = {
@@ -20,6 +22,7 @@ local OVERLAY_PRIORITIES = {
 }
 
 local service_records = setmetatable({}, { __mode = "k" })
+local cursor_lease_records = setmetatable({}, { __mode = "k" })
 
 local FEATURE_GROUPS = {
   "CleverFCursor",
@@ -85,6 +88,8 @@ local function require_host(host)
     or type(host.define_highlight_group) ~= "function"
     or type(host.create_highlight) ~= "function"
     or type(host.remove_highlight) ~= "function"
+    or type(host.suppress_cursor_presentation) ~= "function"
+    or type(host.restore_cursor_presentation) ~= "function"
   then
     fail("FeedbackService host must provide highlight groups", 3)
   end
@@ -134,6 +139,59 @@ function FeedbackService.is(value)
   return type(value) == "table" and service_records[value] ~= nil
 end
 
+local cursor_lease_metatable = {
+  __index = function(lease, key)
+    local method = CursorPresentationLease[key]
+    if method ~= nil then
+      return method
+    end
+    local record = cursor_lease_records[lease]
+    if key == "identity" then
+      return record.identity
+    end
+    if key == "active" then
+      return record.active
+    end
+    return nil
+  end,
+  __newindex = function()
+    fail("cursor presentation leases are read-only", 2)
+  end,
+  __metatable = "clever_f.feedback_service.CursorPresentationLease",
+}
+
+local function new_cursor_presentation_lease(host)
+  local lease = setmetatable({}, cursor_lease_metatable)
+  local identity = host:suppress_cursor_presentation()
+  cursor_lease_records[lease] = {
+    host = host,
+    identity = identity,
+    active = identity ~= nil,
+  }
+  return lease
+end
+
+function CursorPresentationLease.is(value)
+  return type(value) == "table" and cursor_lease_records[value] ~= nil
+end
+
+function CursorPresentationLease:release()
+  local record = cursor_lease_records[self]
+  if record == nil then
+    fail("cursor presentation lease is invalid", 2)
+  end
+  if not record.active then
+    return false
+  end
+  record.host:restore_cursor_presentation(record.identity)
+  record.active = false
+  return true
+end
+
+function FeedbackService:create_cursor_presentation_lease()
+  return new_cursor_presentation_lease(service_records[self].host)
+end
+
 function FeedbackService:create_cursor_marker(position, window)
   position = domain.Position.coerce(position)
   if window == nil then