Split up compilation of rwlock to separate files.

It is much easier to follow this way.

Signed-off-by: Chris Lalancette <[email protected]>

Author: clalancette

CMakeLists.txt

@@ -42,10 +42,24 @@ if(NOT WIN32)
   add_compile_options(-Wall -Wextra -Wconversion -Wno-sign-conversion -Wpedantic)
 endif()
 
+option(FORCE_STUB_RWLOCK "Force the use of a 'stub' rwlock implementation, which makes logging slower and inherently racy." OFF)
+
 if(WIN32)
   set(time_impl_c src/time_win32.c)
+  set(rwlock_impl_c src/rwlock_win32.c)
 else()
   set(time_impl_c src/time_unix.c)
+  find_package(Threads QUIET)
+  if(Threads_FOUND)
+    set(rwlock_impl_c src/rwlock_pthread.c)
+  else()
+    if(FORCE_STUB_RWLOCK)
+      set(rwlock_impl_c src/rwlock_stub.c)
+      add_definitions(-DRWLOCK_STUB)
+    else()
+      message(FATAL "No valid rwlock implementation found!")
+    endif()
+  endif()
 endif()
 
 set(rcutils_sources
@@ -63,7 +77,7 @@ set(rcutils_sources
   src/process.c
   src/qsort.c
   src/repl_str.c
-  src/rwlock.c
+  ${rwlock_impl_c}
   src/sha256.c
   src/shared_library.c
   src/snprintf.c

src/logging.c

@@ -983,6 +983,11 @@ int rcutils_logging_get_logger_effective_level(const char * name)
     severity = g_rcutils_logging_default_logger_level;
   }
 
+#if !defined(RWLOCK_STUB)
+  // If the RWLOCK implementation is a stub, this will definitely cause corruption, even between get
+  // calls, so we skip it (the consequence is that log level lookups are slower).  With a stub
+  // RWLOCK there is still a race between get and set, but that is less common.
+
   // If the calculated severity is anything but UNSET, we place it into the hashmap for speedier
   // lookup next time.  If the severity is UNSET, we don't bother because we are going to have to
   // walk the hierarchy next time anyway.
@@ -995,6 +1000,7 @@ int rcutils_logging_get_logger_effective_level(const char * name)
         "Failed to cache severity; this is not fatal but will impact performance\n");
     }
   }
+#endif
 
   return severity;
 }

src/rwlock_pthread.c

@@ -0,0 +1,126 @@
+// Copyright 2023 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <pthread.h>
+#include <stdlib.h>
+
+#include "./rwlock.h"  // NOLINT
+
+#include "rcutils/allocator.h"
+#include "rcutils/error_handling.h"
+#include "rcutils/types/rcutils_ret.h"
+
+typedef struct rcutils_rwlock_impl_s
+{
+  pthread_rwlock_t lock;
+  rcutils_allocator_t allocator;
+} rcutils_rwlock_impl_t;
+
+rcutils_rwlock_t
+rcutils_get_zero_initialized_rwlock(void)
+{
+  static rcutils_rwlock_t zero_initialized_rwlock;
+  zero_initialized_rwlock.impl = NULL;
+  return zero_initialized_rwlock;
+}
+
+rcutils_ret_t
+rcutils_rwlock_init(rcutils_rwlock_t * lock, rcutils_allocator_t allocator)
+{
+  RCUTILS_CHECK_ARGUMENT_FOR_NULL(lock, RCUTILS_RET_INVALID_ARGUMENT);
+  if (lock->impl != NULL) {
+    RCUTILS_SET_ERROR_MSG("rwlock already initialized");
+    return RCUTILS_RET_ERROR;
+  }
+  RCUTILS_CHECK_ALLOCATOR_WITH_MSG(
+    &allocator, "invalid allocator", return RCUTILS_RET_INVALID_ARGUMENT);
+
+  lock->impl = allocator.allocate(sizeof(rcutils_rwlock_impl_t), allocator.state);
+  if (NULL == lock->impl) {
+    RCUTILS_SET_ERROR_MSG("failed to allocate memory for string map impl struct");
+    return RCUTILS_RET_BAD_ALLOC;
+  }
+
+  lock->impl->allocator = allocator;
+
+  return pthread_rwlock_init(&lock->impl->lock, NULL) == 0 ? RCUTILS_RET_OK : RCUTILS_RET_ERROR;
+}
+
+rcutils_ret_t
+rcutils_rwlock_read_lock(rcutils_rwlock_t * lock)
+{
+  RCUTILS_CHECK_ARGUMENT_FOR_NULL(lock, RCUTILS_RET_INVALID_ARGUMENT);
+  RCUTILS_CHECK_FOR_NULL_WITH_MSG(
+    lock->impl, "invalid lock", return RCUTILS_RET_ERROR);
+
+  return pthread_rwlock_rdlock(&lock->impl->lock) == 0 ? RCUTILS_RET_OK : RCUTILS_RET_ERROR;
+}
+
+rcutils_ret_t
+rcutils_rwlock_read_unlock(rcutils_rwlock_t * lock)
+{
+  RCUTILS_CHECK_ARGUMENT_FOR_NULL(lock, RCUTILS_RET_INVALID_ARGUMENT);
+  RCUTILS_CHECK_FOR_NULL_WITH_MSG(
+    lock->impl, "invalid lock", return RCUTILS_RET_ERROR);
+
+  return pthread_rwlock_unlock(&lock->impl->lock) == 0 ? RCUTILS_RET_OK : RCUTILS_RET_ERROR;
+}
+
+rcutils_ret_t
+rcutils_rwlock_write_trylock(rcutils_rwlock_t * lock)
+{
+  RCUTILS_CHECK_ARGUMENT_FOR_NULL(lock, RCUTILS_RET_INVALID_ARGUMENT);
+  RCUTILS_CHECK_FOR_NULL_WITH_MSG(
+    lock->impl, "invalid lock", return RCUTILS_RET_ERROR);
+
+  return pthread_rwlock_trywrlock(&lock->impl->lock) == 0 ? RCUTILS_RET_OK : RCUTILS_RET_ERROR;
+}
+
+rcutils_ret_t
+rcutils_rwlock_write_lock(rcutils_rwlock_t * lock)
+{
+  RCUTILS_CHECK_ARGUMENT_FOR_NULL(lock, RCUTILS_RET_INVALID_ARGUMENT);
+  RCUTILS_CHECK_FOR_NULL_WITH_MSG(
+    lock->impl, "invalid lock", return RCUTILS_RET_ERROR);
+
+  return pthread_rwlock_wrlock(&lock->impl->lock) == 0 ? RCUTILS_RET_OK : RCUTILS_RET_ERROR;
+}
+
+rcutils_ret_t
+rcutils_rwlock_write_unlock(rcutils_rwlock_t * lock)
+{
+  RCUTILS_CHECK_ARGUMENT_FOR_NULL(lock, RCUTILS_RET_INVALID_ARGUMENT);
+  RCUTILS_CHECK_FOR_NULL_WITH_MSG(
+    lock->impl, "invalid lock", return RCUTILS_RET_ERROR);
+
+  return pthread_rwlock_unlock(&lock->impl->lock) == 0 ? RCUTILS_RET_OK : RCUTILS_RET_ERROR;
+}
+
+rcutils_ret_t
+rcutils_rwlock_fini(rcutils_rwlock_t * lock)
+{
+  RCUTILS_CHECK_ARGUMENT_FOR_NULL(lock, RCUTILS_RET_INVALID_ARGUMENT);
+  if (NULL == lock->impl) {
+    return RCUTILS_RET_OK;
+  }
+
+  int retval = pthread_rwlock_destroy(&lock->impl->lock);
+
+  rcutils_allocator_t allocator = lock->impl->allocator;
+
+  allocator.deallocate(lock->impl, allocator.state);
+  lock->impl = NULL;
+
+  return retval == 0 ? RCUTILS_RET_OK : RCUTILS_RET_ERROR;
+}

src/rwlock_stub.c

@@ -0,0 +1,74 @@
+// Copyright 2023 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "./rwlock.h"  // NOLINT
+
+#include "rcutils/allocator.h"
+#include "rcutils/types/rcutils_ret.h"
+
+rcutils_rwlock_t
+rcutils_get_zero_initialized_rwlock(void)
+{
+  return RCUTILS_RET_OK;
+}
+
+rcutils_ret_t
+rcutils_rwlock_init(rcutils_rwlock_t * lock, rcutils_allocator_t allocator)
+{
+  (void)lock;
+  (void)allocator;
+  return RCUTILS_RET_OK;
+}
+
+rcutils_ret_t
+rcutils_rwlock_read_lock(rcutils_rwlock_t * lock)
+{
+  (void)lock;
+  return RCUTILS_RET_OK;
+}
+
+rcutils_ret_t
+rcutils_rwlock_read_unlock(rcutils_rwlock_t * lock)
+{
+  (void)lock;
+  return RCUTILS_RET_OK;
+}
+
+rcutils_ret_t
+rcutils_rwlock_write_lock(rcutils_rwlock_t * lock)
+{
+  (void)lock;
+  return RCUTILS_RET_OK;
+}
+
+rcutils_ret_t
+rcutils_rwlock_write_trylock(rcutils_rwlock_t * lock)
+{
+  (void)lock;
+  return RCUTILS_RET_OK;
+}
+
+rcutils_ret_t
+rcutils_rwlock_write_unlock(rcutils_rwlock_t * lock)
+{
+  (void)lock;
+  return RCUTILS_RET_OK;
+}
+
+rcutils_ret_t
+rcutils_rwlock_fini(rcutils_rwlock_t * lock)
+{
+  (void)lock;
+  return RCUTILS_RET_OK;
+}