Add the 'txn' date/time format. Change CURRENT_TIMESTAMP and similar to use

'tnx'-style semantics instead of 'now'-style.

FossilOrigin-Name: 61cc8ed8d3541eddf23a9d542179c3f0223c5b8519b54d3be79988a376e25a89

4 files changed, 37 insertions, 17 deletions

diff --git a/src/date.c b/src/date.c
index a3e58bc4e..8546b5dc8 100644
--- a/src/date.c
+++ b/src/date.c
@@ -331,12 +331,16 @@ static int parseYyyyMmDd(const char *zDate, DateTime *p){
 }
 
 /*
-** Set the time to the current time reported by the VFS.
+** Set the time to the current time reported for the prepared statement
+** that is currently executing.  The same time is reported for all
+** invocations of this routine from within the same call to sqlite3_step().
+**
+** Or if bTxn is true, use the transaction time.
 **
 ** Return the number of errors.
 */
-static int setDateTimeToCurrent(sqlite3_context *context, DateTime *p){
-  p->iJD = sqlite3StmtCurrentTime(context);
+static int setCurrentStmtTime(sqlite3_context *context, DateTime *p, int bTxn){
+  p->iJD = sqlite3StmtCurrentTime(context, bTxn);
   if( p->iJD>0 ){
     p->validJD = 1;
     return 0;
@@ -387,7 +391,9 @@ static int parseDateOrTime(
   }else if( parseHhMmSs(zDate, p)==0 ){
     return 0;
   }else if( sqlite3StrICmp(zDate,"now")==0 && sqlite3NotPureFunc(context) ){
-    return setDateTimeToCurrent(context, p);
+    return setCurrentStmtTime(context, p, 0);
+  }else if( sqlite3StrICmp(zDate,"txn")==0 && sqlite3NotPureFunc(context) ){
+    return setCurrentStmtTime(context, p, 1);
   }else if( sqlite3AtoF(zDate, &r, sqlite3Strlen30(zDate), SQLITE_UTF8)>0 ){
     setRawDateNumber(p, r);
     return 0;
@@ -931,8 +937,11 @@ static int parseModifier(
 ** the resulting time into the DateTime structure p.  Return 0
 ** on success and 1 if there are any errors.
 **
-** If there are zero parameters (if even argv[0] is undefined)
-** then assume a default value of "now" for argv[0].
+** If there are zero parameters (if argc<=0) then assume a default
+** value of "now" for argv[0] if argc==0 and "txn" if argc<0.  SQL
+** functions will always have argc>=0, but the special implementations
+** of CURRENT_TIME, CURRENT_DATE, and CURRENT_TIMESTAMP set argc to -1
+** in order to force the use of 'txn' semantics.
 */
 static int isDate(
   sqlite3_context *context, 
@@ -944,9 +953,9 @@ static int isDate(
   const unsigned char *z;
   int eType;
   memset(p, 0, sizeof(*p));
-  if( argc==0 ){
+  if( argc<=0 ){
     if( !sqlite3NotPureFunc(context) ) return 1;
-    return setDateTimeToCurrent(context, p);
+    return setCurrentStmtTime(context, p, argc<0);
   }
   if( (eType = sqlite3_value_type(argv[0]))==SQLITE_FLOAT
                    || eType==SQLITE_INTEGER ){
@@ -1253,7 +1262,7 @@ static void ctimeFunc(
   sqlite3_value **NotUsed2
 ){
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
-  timeFunc(context, 0, 0);
+  timeFunc(context, -1, 0);
 }
 
 /*
@@ -1267,7 +1276,7 @@ static void cdateFunc(
   sqlite3_value **NotUsed2
 ){
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
-  dateFunc(context, 0, 0);
+  dateFunc(context, -1, 0);
 }
 
 /*
@@ -1281,7 +1290,7 @@ static void ctimestampFunc(
   sqlite3_value **NotUsed2
 ){
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
-  datetimeFunc(context, 0, 0);
+  datetimeFunc(context, -1, 0);
 }
 #endif /* !defined(SQLITE_OMIT_DATETIME_FUNCS) */
 
@@ -1312,7 +1321,7 @@ static void currentTimeFunc(
   UNUSED_PARAMETER(argc);
   UNUSED_PARAMETER(argv);
 
-  iT = sqlite3StmtCurrentTime(context);
+  iT = sqlite3StmtCurrentTime(context, 1);
   if( iT<=0 ) return;
   t = iT/1000 - 10000*(sqlite3_int64)21086676;
 #if HAVE_GMTIME_R
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 3da5f13d5..73378dbf6 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1621,6 +1621,7 @@ struct sqlite3 {
   u8 nSqlExec;                  /* Number of pending OP_SqlExec opcodes */
   u8 eOpenState;                /* Current condition of the connection */
   int nextPagesize;             /* Pagesize after VACUUM if >0 */
+  i64 txnTime;                  /* Timestamp for current transaction */
   i64 nChange;                  /* Value returned by sqlite3_changes() */
   i64 nTotalChange;             /* Value returned by sqlite3_total_changes() */
   int aLimit[SQLITE_N_LIMIT];   /* Limits */
@@ -5340,7 +5341,7 @@ FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
     && !defined(SQLITE_OMIT_VIRTUALTABLE)
   void sqlite3VtabUsesAllSchemas(sqlite3_index_info*);
 #endif
-sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context*);
+sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context*, int);
 int sqlite3VdbeParameterIndex(Vdbe*, const char*, int);
 int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
 void sqlite3ParseObjectInit(Parse*,sqlite3*);
diff --git a/src/vdbeapi.c b/src/vdbeapi.c
index 476b6a2ad..722d1215f 100644
--- a/src/vdbeapi.c
+++ b/src/vdbeapi.c
@@ -970,18 +970,27 @@ int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut){
 ** statement, the exact same time is returned for each invocation regardless
 ** of the amount of time that elapses between invocations.  In other words,
 ** the time returned is always the time of the first call.
+**
+** Or, if bTxn, return the transaction time.  The transaction time is the
+** same for all calls within the same transaction.
+**
+** bTxn is 0 for SQL like datetime('now') and is 1 for datetime('txn').
 */
-sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context *p){
+sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context *p, int bTxn){
   int rc;
 #ifndef SQLITE_ENABLE_STAT4
-  sqlite3_int64 *piTime = &p->pVdbe->iCurrentTime;
+  sqlite3_int64 *piTime;
+  sqlite3 *db = p->pOut->db;
   assert( p->pVdbe!=0 );
+  piTime = bTxn ? &db->txnTime : &p->pVdbe->iCurrentTime;
 #else
   sqlite3_int64 iTime = 0;
-  sqlite3_int64 *piTime = p->pVdbe!=0 ? &p->pVdbe->iCurrentTime : &iTime;
+  sqlite3_int64 *piTime;
+  sqlite3 *db = p->pOut->db;
+  piTime = bTxn ? &db->txnTime : p->pVdbe!=0 ? &p->pVdbe->iCurrentTime : &iTime;
 #endif
   if( *piTime==0 ){
-    rc = sqlite3OsCurrentTimeInt64(p->pOut->db->pVfs, piTime);
+    rc = sqlite3OsCurrentTimeInt64(db->pVfs, piTime);
     if( rc ) *piTime = 0;
   }
   return *piTime;
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index d04d8f1e1..82dc60715 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -3394,6 +3394,7 @@ int sqlite3VdbeHalt(Vdbe *p){
   */
   if( db->autoCommit ){
     sqlite3ConnectionUnlocked(db);
+    db->txnTime = 0;
   }
 
   assert( db->nVdbeActive>0 || db->autoCommit==0 || db->nStatement==0 );