From 0675702c629666b271c5ca780bf41bc9432c8c31 Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Wed, 2 Dec 2020 11:21:14 -0800
Subject: [PATCH] Make libcutils' thread local stuff more clearly deprecated.

libcutils' thread local stuff is almost unused already, so let's try
harder to prevent new users. (In parallel I'll try to actually move the
four existing users off it, so we can actually remove this.)

Test: treehugger
Change-Id: Ib5445a43cff1f161ce1c7a45959d5b126f6f6980
---
 libcutils/include/cutils/threads.h | 48 ++++++++++--------------------
 libcutils/threads.cpp              | 39 +-----------------------
 2 files changed, 17 insertions(+), 70 deletions(-)

diff --git a/libcutils/include/cutils/threads.h b/libcutils/include/cutils/threads.h
index ba4846e33..bbbba6d57 100644
--- a/libcutils/include/cutils/threads.h
+++ b/libcutils/include/cutils/threads.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef _LIBS_CUTILS_THREADS_H
-#define _LIBS_CUTILS_THREADS_H
+#pragma once
 
 #include  <sys/types.h>
 
@@ -29,16 +28,6 @@
 extern "C" {
 #endif
 
-//
-// Deprecated: use android::base::GetThreadId instead, which doesn't truncate on Mac/Windows.
-//
-
-extern pid_t gettid();
-
-//
-// Deprecated: use `_Thread_local` in C or `thread_local` in C++.
-//
-
 #if !defined(_WIN32)
 
 typedef struct {
@@ -49,29 +38,24 @@ typedef struct {
 
 #define  THREAD_STORE_INITIALIZER  { PTHREAD_MUTEX_INITIALIZER, 0, 0 }
 
-#else // !defined(_WIN32)
+#endif
 
-typedef struct {
-    int               lock_init;
-    int               has_tls;
-    DWORD             tls;
-    CRITICAL_SECTION  lock;
-} thread_store_t;
+//
+// Deprecated: use android::base::GetThreadId instead, which doesn't truncate on Mac/Windows.
+//
+extern pid_t gettid();
 
-#define  THREAD_STORE_INITIALIZER  { 0, 0, 0, {0, 0, 0, 0, 0, 0} }
-
-#endif // !defined(_WIN32)
-
-typedef void  (*thread_store_destruct_t)(void*  value);
-
-extern void*  thread_store_get(thread_store_t*  store);
-
-extern void   thread_store_set(thread_store_t*          store,
-                               void*                    value,
-                               thread_store_destruct_t  destroy);
+//
+// Deprecated: use `_Thread_local` in C or `thread_local` in C++.
+//
+#if !defined(_WIN32)
+typedef void (*thread_store_destruct_t)(void* x);
+extern void* thread_store_get(thread_store_t* x)
+        __attribute__((__deprecated__("use thread_local instead")));
+extern void thread_store_set(thread_store_t* x, void* y, thread_store_destruct_t z)
+        __attribute__((__deprecated__("use thread_local instead")));
+#endif
 
 #ifdef __cplusplus
 }
 #endif
-
-#endif /* _LIBS_CUTILS_THREADS_H */
diff --git a/libcutils/threads.cpp b/libcutils/threads.cpp
index a7e6b2d8e..eac63b5b2 100644
--- a/libcutils/threads.cpp
+++ b/libcutils/threads.cpp
@@ -47,7 +47,6 @@ pid_t gettid() {
 #endif  // __ANDROID__
 
 #if !defined(_WIN32)
-
 void*  thread_store_get( thread_store_t*  store )
 {
     if (!store->has_tls)
@@ -72,40 +71,4 @@ extern void   thread_store_set( thread_store_t*          store,
 
     pthread_setspecific( store->tls, value );
 }
-
-#else /* !defined(_WIN32) */
-void*  thread_store_get( thread_store_t*  store )
-{
-    if (!store->has_tls)
-        return NULL;
-
-    return (void*) TlsGetValue( store->tls );
-}
-
-void   thread_store_set( thread_store_t*          store,
-                         void*                    value,
-                         thread_store_destruct_t  /*destroy*/ )
-{
-    /* XXX: can't use destructor on thread exit */
-    if (!store->lock_init) {
-        store->lock_init = -1;
-        InitializeCriticalSection( &store->lock );
-        store->lock_init = -2;
-    } else while (store->lock_init != -2) {
-        Sleep(10); /* 10ms */
-    }
-
-    EnterCriticalSection( &store->lock );
-    if (!store->has_tls) {
-        store->tls = TlsAlloc();
-        if (store->tls == TLS_OUT_OF_INDEXES) {
-            LeaveCriticalSection( &store->lock );
-            return;
-        }
-        store->has_tls = 1;
-    }
-    LeaveCriticalSection( &store->lock );
-
-    TlsSetValue( store->tls, value );
-}
-#endif /* !defined(_WIN32) */
+#endif