1 files changed, 57 insertions, 0 deletions
diff --git a/lib/core/rlocks.nim b/lib/core/rlocks.nim
new file mode 100644
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+++ b/lib/core/rlocks.nim
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+#
+#
+#            Nim's Runtime Library
+#        (c) Copyright 2016 Anatoly Galiulin
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module contains Nim's support for reentrant locks.
+
+
+when not compileOption("threads") and not defined(nimdoc):
+  when false:
+    # make rlocks modlue consistent with locks module,
+    # so they can replace each other seamlessly.
+    {.error: "Rlocks requires --threads:on option.".}
+
+import std/private/syslocks
+
+type
+  RLock* = SysLock ## Nim lock, re-entrant
+
+proc initRLock*(lock: var RLock) {.inline.} =
+  ## Initializes the given lock.
+  when defined(posix):
+    var a: SysLockAttr
+    initSysLockAttr(a)
+    setSysLockType(a, SysLockType_Reentrant)
+    initSysLock(lock, a.addr)
+  else:
+    initSysLock(lock)
+
+proc deinitRLock*(lock: RLock) {.inline.} =
+  ## Frees the resources associated with the lock.
+  deinitSys(lock)
+
+proc tryAcquire*(lock: var RLock): bool {.inline.} =
+  ## Tries to acquire the given lock. Returns `true` on success.
+  result = tryAcquireSys(lock)
+
+proc acquire*(lock: var RLock) {.inline.} =
+  ## Acquires the given lock.
+  acquireSys(lock)
+
+proc release*(lock: var RLock) {.inline.} =
+  ## Releases the given lock.
+  releaseSys(lock)
+
+template withRLock*(lock: RLock, code: untyped) =
+  ## Acquires the given lock and then executes the code.
+  acquire(lock)
+  {.locks: [lock].}:
+    try:
+      code
+    finally:
+      release(lock)