Change Future identifier type from `int` to `uint`. (#228)

* Change Future identifier type from `int` to `uint64`.

* Fix compilation error and tests.

* Add integer overflow test, to avoid confusion with next Nim versions, we expect that unsigned integers do not raise any exceptions if overflow happens.

* Switch from `uint64` to `uint` type.

* Add `uint` overflow tests.

chronos/asyncfutures2.nim

@@ -9,6 +9,7 @@
 #                MIT license (LICENSE-MIT)
 
 import std/[os, tables, strutils, heapqueue, options, deques, sequtils]
+import stew/base10
 import ./srcloc
 export srcloc
 
@@ -38,7 +39,7 @@ type
     state*: FutureState
     error*: ref CatchableError ## Stored exception
     mustCancel*: bool
-    id*: int
+    id*: uint64
 
     when defined(chronosStackTrace):
       errorStackTrace*: StackTrace
@@ -75,10 +76,10 @@ type
   FutureList* = object
     head*: FutureBase
     tail*: FutureBase
-    count*: int
+    count*: uint
 
-var currentID* {.threadvar.}: int
+var currentID* {.threadvar.}: uint64
-currentID = 0
+currentID = 0'u64
 
 when defined(chronosFutureTracking):
   var futureList* {.threadvar.}: FutureList
@@ -86,12 +87,12 @@ when defined(chronosFutureTracking):
 
 template setupFutureBase(loc: ptr SrcLoc) =
   new(result)
+  currentID.inc()
   result.state = FutureState.Pending
   when defined(chronosStackTrace):
     result.stackTrace = getStackTrace()
   result.id = currentID
   result.location[LocCreateIndex] = loc
-  currentID.inc()
 
   when defined(chronosFutureTracking):
     result.next = nil
@@ -198,7 +199,7 @@ proc checkFinished(future: FutureBase, loc: ptr SrcLoc) =
     var msg = ""
     msg.add("An attempt was made to complete a Future more than once. ")
     msg.add("Details:")
-    msg.add("\n  Future ID: " & $future.id)
+    msg.add("\n  Future ID: " & Base10.toString(future.id))
     msg.add("\n  Creation location:")
     msg.add("\n    " & $future.location[LocCreateIndex])
     msg.add("\n  First completion location:")

chronos/asyncloop.nim

@@ -1112,7 +1112,7 @@ when defined(chronosFutureTracking):
       yield slider
       slider = slider.next
 
-  proc pendingFuturesCount*(): int =
+  proc pendingFuturesCount*(): uint =
     ## Returns number of pending Futures (Future[T] objects which not yet
     ## completed, cancelled or failed).
     futureList.count

chronos/debugutils.nim

@@ -12,6 +12,9 @@
 import ./asyncloop
 export asyncloop
 
+when defined(chronosFutureTracking):
+  import stew/base10
+
 const
   AllFutureStates* = {FutureState.Pending, FutureState.Cancelled,
                       FutureState.Finished, FutureState.Failed}
@@ -28,7 +31,7 @@ proc dumpPendingFutures*(filter = AllFutureStates): string =
   ##    not yet finished).
   ## 2. Future[T] objects with ``FutureState.Finished/Cancelled/Failed`` state
   ##    which callbacks are scheduled, but not yet fully processed.
-  var count = 0
+  var count = 0'u
   var res = ""
   when defined(chronosFutureTracking):
     for item in pendingFutures():
@@ -41,13 +44,16 @@ proc dumpPendingFutures*(filter = AllFutureStates): string =
           "\"unspecified\""
         else:
           "\"" & procedure & "\""
-        let item = "Future[" & $item.id & "] with name " & $procname &
+        let item = "Future[" & Base10.toString(item.id) & "] with name " &
-                   " created at " & "<" & filename & ":" & $loc.line & ">" &
+                   $procname & " created at " & "<" & filename & ":" &
+                   Base10.toString(uint(loc.line)) & ">" &
                    " and state = " & $item.state & "\n"
         res.add(item)
-  result = $count & " pending Future[T] objects found:\n" & $res
+    Base10.toString(count) & " pending Future[T] objects found:\n" & $res
+  else:
+    "0 pending Future[T] objects found\n"
 
-proc pendingFuturesCount*(filter: set[FutureState]): int =
+proc pendingFuturesCount*(filter: set[FutureState]): uint =
   ## Returns number of `pending` Future[T] objects which satisfy the ``filter``
   ## condition.
   ##
@@ -57,10 +63,10 @@ proc pendingFuturesCount*(filter: set[FutureState]): int =
     if filter == AllFutureStates:
       pendingFuturesCount()
     else:
-      var res = 0
+      var res = 0'u
       for item in pendingFutures():
         if item.state in filter:
           inc(res)
       res
   else:
-    0
+    0'u

tests/testfut.nim

@@ -1315,4 +1315,39 @@ suite "Future[T] behavior test suite":
       f2.finished()
       f3.finished()
 
+  test "Unsigned integer overflow test":
+    check:
+      0xFFFF_FFFF_FFFF_FFFF'u64 + 1'u64 == 0'u64
+      0xFFFF_FFFF'u32 + 1'u32 == 0'u32
 
+    when sizeof(uint) == 8:
+      check 0xFFFF_FFFF_FFFF_FFFF'u + 1'u == 0'u
+    else:
+      check 0xFFFF_FFFF'u + 1'u == 0'u
+
+    var v1_64 = 0xFFFF_FFFF_FFFF_FFFF'u64
+    var v2_64 = 0xFFFF_FFFF_FFFF_FFFF'u64
+    var v1_32 = 0xFFFF_FFFF'u32
+    var v2_32 = 0xFFFF_FFFF'u32
+    inc(v1_64)
+    inc(v1_32)
+    check:
+      v1_64 == 0'u64
+      v2_64 + 1'u64 == 0'u64
+      v1_32 == 0'u32
+      v2_32 + 1'u32 == 0'u32
+
+    when sizeof(uint) == 8:
+      var v1_u = 0xFFFF_FFFF_FFFF_FFFF'u
+      var v2_u = 0xFFFF_FFFF_FFFF_FFFF'u
+      inc(v1_u)
+      check:
+        v1_u == 0'u
+        v2_u + 1'u == 0'u
+    else:
+      var v1_u = 0xFFFF_FFFF'u
+      var v2_u = 0xFFFF_FFFF'u
+      inc(v1_u)
+      check:
+        v1_u == 0'u
+        v2_u + 1'u == 0'u

tests/testutils.nim

@@ -12,19 +12,20 @@ when defined(nimHasUsed): {.used.}
 
 suite "Asynchronous utilities test suite":
   when defined(chronosFutureTracking):
-    proc getCount(): int =
+    proc getCount(): uint =
       # This procedure counts number of Future[T] in double-linked list via list
       # iteration.
-      result = 0
+      var res = 0'u
       for item in pendingFutures():
-        inc(result)
+        inc(res)
+      res
 
   test "Future clean and leaks test":
     when defined(chronosFutureTracking):
-      if pendingFuturesCount(WithoutFinished) == 0:
+      if pendingFuturesCount(WithoutFinished) == 0'u:
-        if pendingFuturesCount(OnlyFinished) > 0:
+        if pendingFuturesCount(OnlyFinished) > 0'u:
           poll()
-        check pendingFuturesCount() == 0
+        check pendingFuturesCount() == 0'u
       else:
         echo dumpPendingFutures()
         check false
@@ -35,31 +36,31 @@ suite "Asynchronous utilities test suite":
     when defined(chronosFutureTracking):
       var fut1 = newFuture[void]()
       check:
-        getCount() == 1
+        getCount() == 1'u
-        pendingFuturesCount() == 1
+        pendingFuturesCount() == 1'u
       var fut2 = newFuture[void]()
       check:
-        getCount() == 2
+        getCount() == 2'u
-        pendingFuturesCount() == 2
+        pendingFuturesCount() == 2'u
       var fut3 = newFuture[void]()
       check:
-        getCount() == 3
+        getCount() == 3'u
-        pendingFuturesCount() == 3
+        pendingFuturesCount() == 3'u
       fut1.complete()
       poll()
       check:
-        getCount() == 2
+        getCount() == 2'u
-        pendingFuturesCount() == 2
+        pendingFuturesCount() == 2'u
       fut2.fail(newException(ValueError, ""))
       poll()
       check:
-        getCount() == 1
+        getCount() == 1'u
-        pendingFuturesCount() == 1
+        pendingFuturesCount() == 1'u
       fut3.cancel()
       poll()
       check:
-        getCount() == 0
+        getCount() == 0'u64
-        pendingFuturesCount() == 0
+        pendingFuturesCount() == 0'u64
     else:
       skip()
 
@@ -70,17 +71,17 @@ suite "Asynchronous utilities test suite":
 
       var fut = simpleProc()
       check:
-        getCount() == 2
+        getCount() == 2'u64
-        pendingFuturesCount() == 2
+        pendingFuturesCount() == 2'u64
 
       waitFor fut
       check:
-        getCount() == 1
+        getCount() == 1'u64
-        pendingFuturesCount() == 1
+        pendingFuturesCount() == 1'u64
 
       poll()
       check:
-        getCount() == 0
+        getCount() == 0'u64
-        pendingFuturesCount() == 0
+        pendingFuturesCount() == 0'u64
     else:
       skip()