watching library changes

1 files changed, 78 insertions, 0 deletions

diff --git a/script/filewatch.lua b/script/filewatch.lua
new file mode 100644
index 00000000..fd3b8686
--- /dev/null
+++ b/script/filewatch.lua
@@ -0,0 +1,78 @@
+local fw    = require 'bee.filewatch'
+local fs    = require 'bee.filesystem'
+local await = require 'await'
+
+local MODIFY = 1 << 0
+local RENAME = 1 << 1
+
+---@class filewatch
+local m = {}
+
+m._eventList = {}
+
+function m.watch(path)
+    local id = fw.add(path)
+    return function ()
+        fw.remove(id)
+    end
+end
+
+function m.event(callback)
+    m._eventList[#m._eventList+1] = callback
+end
+
+function m._callEvent(changes)
+    for _, callback in ipairs(m._eventList) do
+        await.call(function ()
+            callback(changes)
+        end)
+    end
+end
+
+function m.update()
+    local collect
+    while true do
+        local ev, path = fw.select()
+        if not ev then
+            break
+        end
+        if not collect then
+            collect = {}
+        end
+        if ev == 'modify' then
+            collect[path] = (collect[path] or 0) | MODIFY
+        elseif ev == 'rename' then
+            collect[path] = (collect[path] or 0) | RENAME
+        end
+    end
+
+    if not collect or not next(collect) then
+        return
+    end
+
+    local changes = {}
+    for path, flag in pairs(collect) do
+        if flag & RENAME ~= 0 then
+            if fs.exists(fs.path(path)) then
+                changes[#changes+1] = {
+                    type = 'create',
+                    path = path,
+                }
+            else
+                changes[#changes+1] = {
+                    type = 'delete',
+                    path = path,
+                }
+            end
+        elseif flag & MODIFY ~= 0 then
+            changes[#changes+1] = {
+                type = 'change',
+                path = path,
+            }
+        end
+    end
+
+    m._callEvent(changes)
+end
+
+return m