Make the distinction between truly deterministic functions and date/time

functions which only return the same answer for a single query.  Only truly
deterministic functions are allowed in indexes.  Add new expression index
test cases.

FossilOrigin-Name: c77554b5c42327106a7b90334e9cc3c07b007c76

1 files changed, 21 insertions, 13 deletions

diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 69f98da26..613f351aa 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1384,18 +1384,19 @@ struct FuncDestructor {
 ** values must correspond to OPFLAG_LENGTHARG and OPFLAG_TYPEOFARG.  There
 ** are assert() statements in the code to verify this.
 */
-#define SQLITE_FUNC_ENCMASK  0x003 /* SQLITE_UTF8, SQLITE_UTF16BE or UTF16LE */
-#define SQLITE_FUNC_LIKE     0x004 /* Candidate for the LIKE optimization */
-#define SQLITE_FUNC_CASE     0x008 /* Case-sensitive LIKE-type function */
-#define SQLITE_FUNC_EPHEM    0x010 /* Ephemeral.  Delete with VDBE */
-#define SQLITE_FUNC_NEEDCOLL 0x020 /* sqlite3GetFuncCollSeq() might be called */
-#define SQLITE_FUNC_LENGTH   0x040 /* Built-in length() function */
-#define SQLITE_FUNC_TYPEOF   0x080 /* Built-in typeof() function */
-#define SQLITE_FUNC_COUNT    0x100 /* Built-in count(*) aggregate */
-#define SQLITE_FUNC_COALESCE 0x200 /* Built-in coalesce() or ifnull() */
-#define SQLITE_FUNC_UNLIKELY 0x400 /* Built-in unlikely() function */
-#define SQLITE_FUNC_CONSTANT 0x800 /* Constant inputs give a constant output */
-#define SQLITE_FUNC_MINMAX  0x1000 /* True for min() and max() aggregates */
+#define SQLITE_FUNC_ENCMASK  0x0003 /* SQLITE_UTF8, SQLITE_UTF16BE or UTF16LE */
+#define SQLITE_FUNC_LIKE     0x0004 /* Candidate for the LIKE optimization */
+#define SQLITE_FUNC_CASE     0x0008 /* Case-sensitive LIKE-type function */
+#define SQLITE_FUNC_EPHEM    0x0010 /* Ephemeral.  Delete with VDBE */
+#define SQLITE_FUNC_NEEDCOLL 0x0020 /* sqlite3GetFuncCollSeq() might be called*/
+#define SQLITE_FUNC_LENGTH   0x0040 /* Built-in length() function */
+#define SQLITE_FUNC_TYPEOF   0x0080 /* Built-in typeof() function */
+#define SQLITE_FUNC_COUNT    0x0100 /* Built-in count(*) aggregate */
+#define SQLITE_FUNC_COALESCE 0x0200 /* Built-in coalesce() or ifnull() */
+#define SQLITE_FUNC_UNLIKELY 0x0400 /* Built-in unlikely() function */
+#define SQLITE_FUNC_CONSTANT 0x0800 /* Constant inputs give a constant output */
+#define SQLITE_FUNC_MINMAX   0x1000 /* True for min() and max() aggregates */
+#define SQLITE_FUNC_DATETIME 0x2000 /* Function returns a date and/or time */
 
 /*
 ** The following three macros, FUNCTION(), LIKEFUNC() and AGGREGATE() are
@@ -1411,6 +1412,10 @@ struct FuncDestructor {
 **   VFUNCTION(zName, nArg, iArg, bNC, xFunc)
 **     Like FUNCTION except it omits the SQLITE_FUNC_CONSTANT flag.
 **
+**   DFUNCTION(zName, nArg, iArg, bNC, xFunc)
+**     Like FUNCTION except it omits the SQLITE_FUNC_CONSTANT flag and
+**     adds the SQLITE_FUNC_DATETIME flag.  Used for date & time functions.
+**
 **   AGGREGATE(zName, nArg, iArg, bNC, xStep, xFinal)
 **     Used to create an aggregate function definition implemented by
 **     the C functions xStep and xFinal. The first four parameters
@@ -1431,6 +1436,9 @@ struct FuncDestructor {
 #define VFUNCTION(zName, nArg, iArg, bNC, xFunc) \
   {nArg, SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
    SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0, 0}
+#define DFUNCTION(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_DATETIME|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0, 0}
 #define FUNCTION2(zName, nArg, iArg, bNC, xFunc, extraFlags) \
   {nArg,SQLITE_FUNC_CONSTANT|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL)|extraFlags,\
    SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName, 0, 0}
@@ -2121,7 +2129,7 @@ struct Expr {
 #define EP_MemToken  0x010000 /* Need to sqlite3DbFree() Expr.zToken */
 #define EP_NoReduce  0x020000 /* Cannot EXPRDUP_REDUCE this Expr */
 #define EP_Unlikely  0x040000 /* unlikely() or likelihood() function */
-#define EP_ConstFunc 0x080000 /* Node is a SQLITE_FUNC_CONSTANT function */
+#define EP_ConstFunc 0x080000 /* A SQLITE_FUNC_CONSTANT or _DATETIME function */
 #define EP_CanBeNull 0x100000 /* Can be null despite NOT NULL constraint */
 #define EP_Subquery  0x200000 /* Tree contains a TK_SELECT operator */