From fe96a72a3e85f2b142d783442e3f2931f562649a Mon Sep 17 00:00:00 2001
From: Eric House <xwords@eehouse.org>
Date: Tue, 2 Apr 2019 11:30:50 -0700
Subject: [PATCH] use mutex to synchronize access to smsproto apis

I'm seeing my simultaneous access assert fail, so might as well break
fix it the foolproof way. It's background threads only that are calling
this stuff on Android so blocking them shouldn't hurt.
---
 xwords4/common/smsproto.c | 47 ++++++++++-----------------------------
 1 file changed, 12 insertions(+), 35 deletions(-)

diff --git a/xwords4/common/smsproto.c b/xwords4/common/smsproto.c
index ea64537c9..a7e36f3bd 100644
--- a/xwords4/common/smsproto.c
+++ b/xwords4/common/smsproto.c
@@ -69,6 +69,7 @@ typedef struct _FromPhoneRec {
 struct SMSProto {
     XW_DUtilCtxt* dutil;
     pthread_t creator;
+    pthread_mutex_t mutex;
     XP_U16 nNextID;
     int lastStoredSize;
     XP_U16 nToPhones;
@@ -83,32 +84,6 @@ struct SMSProto {
     MPSLOT;
 };
 
-#ifdef DEBUG
-# define CHECK_START( state ) {                                 \
-    SMSProto* _state = state;                                   \
-    pthread_t _self = pthread_self();                           \
-    if ( _state->nestCount == 0 ) {                             \
-        XP_ASSERT( _state->starter == 0 );                      \
-        _state->starter = _self;                                \
-    } else {                                                    \
-        XP_ASSERT( _state->starter == _self );                  \
-    }                                                           \
-    ++_state->nestCount;                                        \
-    XP_LOGF( "%s(): check: %d", __func__, _state->nestCount );  \
-
-# define CHECK_END()                                         \
-    if ( --_state->nestCount == 0 ) {                           \
-        _state->starter = 0;                                    \
-    }                                                           \
-    XP_LOGF( "%s(): check: %d", __func__, _state->nestCount );  \
-    }                                                           \
-
-
-#else
-# define CHECK_START(s)
-# define CHECK_END()
-#endif
-
 #define KEY_PARTIALS PERSIST_KEY("partials")
 #define KEY_NEXTID PERSIST_KEY("nextID")
 
@@ -138,6 +113,7 @@ SMSProto*
 smsproto_init( MPFORMAL XW_DUtilCtxt* dutil )
 {
     SMSProto* state = (SMSProto*)XP_CALLOC( mpool, sizeof(*state) );
+    pthread_mutex_init( &state->mutex, NULL );
     state->dutil = dutil;
     MPASSIGN( state->mpool, mpool );
 
@@ -172,6 +148,8 @@ smsproto_free( SMSProto* state )
         }
         XP_ASSERT( !state->fromPhoneRecs ); /* above nulls this once empty */
 
+        pthread_mutex_destroy( &state->mutex );
+
         XP_FREEP( state->mpool, &state );
     }
 }
@@ -234,7 +212,7 @@ smsproto_prepOutbound( SMSProto* state, SMS_CMD cmd, XP_U32 gameID,
 {
     XP_USE( toPort );
     SMSMsgArray* result = NULL;
-    CHECK_START( state );
+    pthread_mutex_lock( &state->mutex );
 
 #ifdef DEBUG
     XP_UCHAR* checksum = dutil_md5sum( state->dutil, buf, buflen );
@@ -273,7 +251,8 @@ smsproto_prepOutbound( SMSProto* state, SMS_CMD cmd, XP_U32 gameID,
 
     XP_LOGF( "%s() => %p (len=%d, *waitSecs=%d)", __func__, result,
              !!result ? result->nMsgs : 0, *waitSecsP );
-    CHECK_END();
+
+    pthread_mutex_unlock( &state->mutex );
     return result;
 }
 
@@ -315,7 +294,7 @@ smsproto_prepInbound( SMSProto* state, const XP_UCHAR* fromPhone,
 {
     XP_LOGF( "%s(): len=%d, fromPhone=%s", __func__, len, fromPhone );
     SMSMsgArray* result = NULL;
-    CHECK_START( state );
+    pthread_mutex_lock( &state->mutex );
 
     XWStreamCtxt* stream = mkStream( state );
     stream_putBytes( stream, data, len );
@@ -383,14 +362,15 @@ smsproto_prepInbound( SMSProto* state, const XP_UCHAR* fromPhone,
     stream_destroy( stream );
 
     XP_LOGF( "%s() => %p (len=%d)", __func__, result, (!!result) ? result->nMsgs : 0 );
-    CHECK_END();
+
+    pthread_mutex_unlock( &state->mutex );
     return result;
 }
 
 void
 smsproto_freeMsgArray( SMSProto* state, SMSMsgArray* arr )
 {
-    CHECK_START( state );
+    pthread_mutex_lock( &state->mutex );
 
     for ( int ii = 0; ii < arr->nMsgs; ++ii ) {
         XP_U8** ptr = arr->format == FORMAT_LOC
@@ -412,7 +392,7 @@ smsproto_freeMsgArray( SMSProto* state, SMSMsgArray* arr )
     }
     XP_FREEP( state->mpool, ptr );
     XP_FREEP( state->mpool, &arr );
-    CHECK_END();
+    pthread_mutex_unlock( &state->mutex );
 }
 
 static void
@@ -644,8 +624,6 @@ freeMsgIDRec( SMSProto* state, MsgIDRec* rec, int fromPhoneIndex, int msgIDIndex
 static void
 savePartials( SMSProto* state )
 {
-    CHECK_START( state );
-
     XWStreamCtxt* stream = mkStream( state );
     stream_putU8( stream, PARTIALS_FORMAT );
 
@@ -679,7 +657,6 @@ savePartials( SMSProto* state )
     stream_destroy( stream );
 
     LOG_RETURN_VOID();
-    CHECK_END();
 } /* savePartials */
 
 static void