From 0a7a290d068a9e28bdb952736470767c2550658a Mon Sep 17 00:00:00 2001
From: Leo Yuriev <leo@yuriev.ru>
Date: Thu, 26 Oct 2017 21:47:41 +0300
Subject: [PATCH] mdbx: drop mdbx_txn_trylock().

---
 src/lck-posix.c   | 12 +++---------
 src/lck-windows.c | 19 ++++++-------------
 src/mdbx.c        | 13 ++++++-------
 src/osal.h        |  3 +--
 4 files changed, 16 insertions(+), 31 deletions(-)

diff --git a/src/lck-posix.c b/src/lck-posix.c
index 2aeed6f4..14ce3d50 100644
--- a/src/lck-posix.c
+++ b/src/lck-posix.c
@@ -213,16 +213,10 @@ void mdbx_rdt_unlock(MDBX_env *env) {
     mdbx_panic("%s() failed: errcode %d\n", mdbx_func_, rc);
 }
 
-int mdbx_txn_lock(MDBX_env *env) {
+int mdbx_txn_lock(MDBX_env *env, bool dontwait) {
   mdbx_trace(">>");
-  int rc = mdbx_robust_lock(env, &env->me_lck->mti_wmutex);
-  mdbx_trace("<< rc %d", rc);
-  return MDBX_IS_ERROR(rc) ? rc : MDBX_SUCCESS;
-}
-
-int mdbx_txn_trylock(MDBX_env *env) {
-  mdbx_trace(">>");
-  int rc = mdbx_robust_trylock(env, &env->me_lck->mti_wmutex);
+  int rc = dontwait ? mdbx_robust_trylock(env, &env->me_lck->mti_wmutex)
+                    : mdbx_robust_lock(env, &env->me_lck->mti_wmutex);
   mdbx_trace("<< rc %d", rc);
   return MDBX_IS_ERROR(rc) ? rc : MDBX_SUCCESS;
 }
diff --git a/src/lck-windows.c b/src/lck-windows.c
index d3340d58..672512a7 100644
--- a/src/lck-windows.c
+++ b/src/lck-windows.c
@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright 2015-2017 Leonid Yuriev <leo@yuriev.ru>
  * and other libmdbx authors: please see AUTHORS file.
  * All rights reserved.
@@ -126,20 +126,13 @@ static __inline BOOL funlock(mdbx_filehandle_t fd, uint64_t offset,
 #define LCK_BODY LCK_BODY_OFFSET, LCK_BODY_LEN
 #define LCK_WHOLE 0, LCK_MAXLEN
 
-int mdbx_txn_lock(MDBX_env *env) {
-  if (flock(env->me_fd, LCK_EXCLUSIVE | LCK_WAITFOR, LCK_BODY))
-    return MDBX_SUCCESS;
-  return GetLastError();
-}
-
-int mdbx_txn_trylock(MDBX_env *env) {
-  if (flock(env->me_fd, LCK_EXCLUSIVE | LCK_DONTWAIT, LCK_BODY))
+int mdbx_txn_lock(MDBX_env *env, bool dontwait) {
+  if (flock(env->me_fd, dontwait ? (LCK_EXCLUSIVE | LCK_DONTWAIT)
+                                 : (LCK_EXCLUSIVE | LCK_WAITFOR),
+            LCK_BODY))
     return MDBX_SUCCESS;
   int rc = GetLastError();
-  if (rc == ERROR_LOCK_VIOLATION) {
-    rc = MDBX_BUSY;
-  }
-  return rc;
+  return (!dontwait || rc != ERROR_LOCK_VIOLATION) ? rc : MDBX_BUSY;
 }
 
 void mdbx_txn_unlock(MDBX_env *env) {
diff --git a/src/mdbx.c b/src/mdbx.c
index 7e480ce3..ace75f93 100644
--- a/src/mdbx.c
+++ b/src/mdbx.c
@@ -2288,7 +2288,7 @@ int mdbx_env_sync(MDBX_env *env, int force) {
       (!env->me_txn0 || env->me_txn0->mt_owner != mdbx_thread_self());
 
   if (outside_txn) {
-    int rc = mdbx_txn_lock(env);
+    int rc = mdbx_txn_lock(env, false);
     if (unlikely(rc != MDBX_SUCCESS))
       return rc;
   }
@@ -2317,7 +2317,7 @@ int mdbx_env_sync(MDBX_env *env, int force) {
       if (unlikely(rc != MDBX_SUCCESS))
         return rc;
 
-      rc = mdbx_txn_lock(env);
+      rc = mdbx_txn_lock(env, false);
       if (unlikely(rc != MDBX_SUCCESS))
         return rc;
 
@@ -2563,8 +2563,7 @@ static int mdbx_txn_renew0(MDBX_txn *txn, unsigned flags) {
   } else {
     /* Not yet touching txn == env->me_txn0, it may be active */
     mdbx_jitter4testing(false);
-    rc = F_ISSET(flags, MDBX_TRYTXN) ? mdbx_txn_trylock(env)
-                                     : mdbx_txn_lock(env);
+    rc = mdbx_txn_lock(env, F_ISSET(flags, MDBX_TRYTXN));
     if (unlikely(rc))
       return rc;
 
@@ -4444,7 +4443,7 @@ LIBMDBX_API int mdbx_env_set_geometry(MDBX_env *env, intptr_t size_lower,
       return MDBX_EACCESS;
 
     if (outside_txn) {
-      int err = mdbx_txn_lock(env);
+      int err = mdbx_txn_lock(env, false);
       if (unlikely(err != MDBX_SUCCESS))
         return err;
     }
@@ -9772,7 +9771,7 @@ static int __cold mdbx_env_copy_asis(MDBX_env *env, mdbx_filehandle_t fd) {
     goto bailout; /* FIXME: or just return? */
 
   /* Temporarily block writers until we snapshot the meta pages */
-  rc = mdbx_txn_lock(env);
+  rc = mdbx_txn_lock(env, false);
   if (unlikely(rc != MDBX_SUCCESS))
     goto bailout;
 
@@ -9857,7 +9856,7 @@ int __cold mdbx_env_set_flags(MDBX_env *env, unsigned flags, int onoff) {
   if (unlikely(flags & ~CHANGEABLE))
     return MDBX_EINVAL;
 
-  int rc = mdbx_txn_lock(env);
+  int rc = mdbx_txn_lock(env, false);
   if (unlikely(rc))
     return rc;
 
diff --git a/src/osal.h b/src/osal.h
index ad9fd275..871e52b0 100644
--- a/src/osal.h
+++ b/src/osal.h
@@ -505,8 +505,7 @@ void mdbx_lck_destroy(MDBX_env *env);
 int mdbx_rdt_lock(MDBX_env *env);
 void mdbx_rdt_unlock(MDBX_env *env);
 
-int mdbx_txn_lock(MDBX_env *env);
-int mdbx_txn_trylock(MDBX_env *env);
+int mdbx_txn_lock(MDBX_env *env, bool dontwait);
 void mdbx_txn_unlock(MDBX_env *env);
 
 int mdbx_rpid_set(MDBX_env *env);