OMP neovim server bridge

lua/nvim_omp/init.lua

@@ -0,0 +1,55 @@
+-- omp bridge: expose an RPC socket so the omp harness can read this Neovim
+-- instance's buffers on demand. Read-only on the agent side; this module only
+-- owns the socket lifecycle.
+--
+-- Contract
+--   * Socket path: $NVIM_OMP_SOCKET if set, else <stdpath('state')>/omp.sock
+--     (~/.local/state/nvim/omp.sock on macOS, ~/.local/state/nvim/omp.sock
+--     elsewhere). The omp-side tool in .omp/tools/nvim_buffers.mjs resolves the
+--     *same* path, so the two sides agree without configuration.
+--   * The agent reads buffers by evaluating read-only nvim API expressions over
+--     the socket with `nvim --server <path> --remote-expr 'json_encode(...)'`.
+--     Nothing here writes buffers or executes model-supplied commands.
+local M = {}
+
+local SOCKET_NAME = "omp.sock"
+
+-- Resolve the deterministic socket path. Copies the rule on the omp side; keep
+-- the two files in sync when changing the fallback or env override.
+function M.socket_path()
+  local env = vim.env.NVIM_OMP_SOCKET
+  if env and env ~= "" then
+    return env
+  end
+  return vim.fn.stdpath("state") .. "/" .. SOCKET_NAME
+end
+
+-- Start the RPC listener. Returns the live socket path, or nil.
+-- A second instance cannot bind the same address. This function deliberately
+-- never removes an existing socket file: a failed liveness probe must not
+-- disconnect another live Neovim instance.
+-- If a crash leaves a stale socket, remove it manually only after confirming
+-- that no Neovim process owns the path, then restart vv.
+function M.start()
+  if vim.v.headless == 1 then
+    -- Headless runs (tests, CI) get no socket; nothing should depend on one.
+    return nil
+  end
+
+  local path = M.socket_path()
+  local ok, res = pcall(vim.fn.serverstart, path)
+  if ok and type(res) == "string" and res ~= "" then
+    -- serverstart returns the bound address string (e.g. "/tmp/omp.sock").
+    vim.notify("nvim_omp: RPC socket ready at " .. path, vim.log.levels.INFO)
+    return path
+  end
+
+  vim.notify(
+    "nvim_omp: could not bind RPC socket at " .. path
+    .. "; another instance may own it or a stale socket needs manual cleanup.",
+    vim.log.levels.WARN
+  )
+  return nil
+end
+
+return M