Enhance SQLITE_TESTCTRL_LOCALTIME_FAULT so that is able to install an

alternative localtime() interface so that the localtime logic an be better
tested.

FossilOrigin-Name: 6e25cb0890e8cdc63c9a21e841844d066267fc32ad143527843f7c8d05612b53

5 files changed, 38 insertions, 8 deletions

diff --git a/src/date.c b/src/date.c
index 3225a5528..1306847f8 100644
--- a/src/date.c
+++ b/src/date.c
@@ -503,8 +503,10 @@ static void clearYMD_HMS_TZ(DateTime *p){
 ** is available.  This routine returns 0 on success and
 ** non-zero on any kind of error.
 **
-** If the sqlite3GlobalConfig.bLocaltimeFault variable is true then this
-** routine will always fail.
+** If the sqlite3GlobalConfig.bLocaltimeFault variable is non-zero then this
+** routine will always fail.  If bLocaltimeFault is nonzero and
+** sqlite3GlobalConfig.xAltLocaltime is not NULL, then xAltLocaltime() is
+** invoked in place of the OS-defined localtime() function.
 **
 ** EVIDENCE-OF: R-62172-00036 In this implementation, the standard C
 ** library function localtime_r() is used to assist in the calculation of
@@ -520,7 +522,13 @@ static int osLocaltime(time_t *t, struct tm *pTm){
   sqlite3_mutex_enter(mutex);
   pX = localtime(t);
 #ifndef SQLITE_UNTESTABLE
-  if( sqlite3GlobalConfig.bLocaltimeFault ) pX = 0;
+  if( sqlite3GlobalConfig.bLocaltimeFault ){
+    if( sqlite3GlobalConfig.xAltLocaltime!=0 ){
+      return sqlite3GlobalConfig.xAltLocaltime((const void*)t,(void*)pTm);
+    }else{
+      pX = 0;
+    }
+  }
 #endif
   if( pX ) *pTm = *pX;
 #if SQLITE_THREADSAFE>0
@@ -529,7 +537,13 @@ static int osLocaltime(time_t *t, struct tm *pTm){
   rc = pX==0;
 #else
 #ifndef SQLITE_UNTESTABLE
-  if( sqlite3GlobalConfig.bLocaltimeFault ) return 1;
+  if( sqlite3GlobalConfig.bLocaltimeFault ){
+    if( sqlite3GlobalConfig.xAltLocaltime!=0 ){
+      return sqlite3GlobalConfig.xAltLocaltime((const void*)t,(void*)pTm);
+    }else{
+      return 1;
+    }
+  }
 #endif
 #if HAVE_LOCALTIME_R
   rc = localtime_r(t, pTm)==0;
diff --git a/src/global.c b/src/global.c
index 34b7d9583..6ad3bb465 100644
--- a/src/global.c
+++ b/src/global.c
@@ -286,6 +286,7 @@ SQLITE_WSD struct Sqlite3Config sqlite3Config = {
    0,                         /* xTestCallback */
 #endif
    0,                         /* bLocaltimeFault */
+   0,                         /* xAltLocaltime */
    0x7ffffffe,                /* iOnceResetThreshold */
    SQLITE_DEFAULT_SORTERREF_SIZE,   /* szSorterRef */
    0,                         /* iPrngSeed */
diff --git a/src/main.c b/src/main.c
index e8b775a21..f34e981d5 100644
--- a/src/main.c
+++ b/src/main.c
@@ -4161,13 +4161,27 @@ int sqlite3_test_control(int op, ...){
       break;
     }
 
-    /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, onoff, xAlt);
     **
-    ** If parameter onoff is non-zero, subsequent calls to localtime()
-    ** and its variants fail. If onoff is zero, undo this setting.
+    ** If parameter onoff is 1, subsequent calls to localtime() fail.
+    ** If 2, then invoke xAlt() instead of localtime().  If 0, normal
+    ** processing.
+    **
+    ** xAlt arguments are void pointers, but they really want to be:
+    **
+    **    int xAlt(const time_t*, struct tm*);
+    **
+    ** xAlt should write results in to struct tm object of its 2nd argument
+    ** and return zero on success, or return non-zero on failure.
     */
     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
+      if( sqlite3GlobalConfig.bLocaltimeFault==2 ){
+        sqlite3GlobalConfig.xAltLocaltime = 
+           va_arg(ap, int(*)(const void*,void*));
+      }else{
+        sqlite3GlobalConfig.xAltLocaltime = 0;
+      }
       break;
     }
 
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 1ed600f4d..c8dbec2f1 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3936,6 +3936,7 @@ struct Sqlite3Config {
   int (*xTestCallback)(int);        /* Invoked by sqlite3FaultSim() */
 #endif
   int bLocaltimeFault;              /* True to fail localtime() calls */
+  int (*xAltLocaltime)(const void*,void*); /* Alternative localtime() routine */
   int iOnceResetThreshold;          /* When to reset OP_Once counters */
   u32 szSorterRef;                  /* Min size in bytes to use sorter-refs */
   unsigned int iPrngSeed;           /* Alternative fixed seed for the PRNG */
diff --git a/src/test1.c b/src/test1.c
index 05aa97539..3eba08449 100644
--- a/src/test1.c
+++ b/src/test1.c
@@ -7258,7 +7258,7 @@ static int SQLITE_TCLAPI test_test_control(
         return TCL_ERROR;
       }
       if( Tcl_GetBooleanFromObj(interp, objv[2], &val) ) return TCL_ERROR;
-      sqlite3_test_control(iFlag, val);
+      sqlite3_test_control(iFlag, val!=0);
       break;
     }