{171428666}: column character encoding

A new `ENCODING` keyword is introduced in this patch, that specifies a character set for a column. Invalid character encoding will be rejected. So far only `"utf8"` and `NONE` are supported. This allows users to conveniently create an indexable utf8 cstring column. It's implemented as a check constraint using the `utf8_validate()` function. Signed-off-by: Rivers Zhang <[email protected]>
bloomberg · Jan 31, 2025 · 00664f0 · 00664f0
1 parent 2dc04c8
commit 00664f0
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Showing 17 changed files with 183 additions and 22 deletions.
diff --git a/db/types.c b/db/types.c
@@ -3695,6 +3695,21 @@ TYPES_INLINE int CLIENT_BLOB_to_CLIENT_PSTR2(
     return -1;
 }
 
+static int utf8_validate_permitting_trailing_zeros(const char *u, int max)
+{
+    int valid_len;
+
+    if (utf8_validate(u, max, &valid_len) != 0)
+        return -1;
+
+    /* utf8_validate() stops at the 1st NUL character. We want to permit trailing zeros */
+    for (; valid_len < max - 1; ++valid_len) {
+        if (u[valid_len] != '\0')
+            return -1;
+    }
+    return 0;
+}
+
 /**
  * Finds out where the input vutf8 string is stored and then determines where it
  * should be copied and copies it. Doesn't deal with NULLs.
@@ -3717,7 +3732,6 @@ static TYPES_INLINE int vutf8_convert(int len, const void *in, int in_len,
                                       blob_buffer_t *inblob,
                                       blob_buffer_t *outblob, int *outdtsz)
 {
-    int valid_len;
     if (out_len > 0)
         memset(out, 0, out_len);
 
@@ -3742,10 +3756,8 @@ static TYPES_INLINE int vutf8_convert(int len, const void *in, int in_len,
             /* validate input blob */
             assert(inblob->length == len);
 
-            if (utf8_validate(inblob->data, inblob->length, &valid_len) ||
-                valid_len != len - 1) {
+            if (utf8_validate_permitting_trailing_zeros(inblob->data, inblob->length))
                 return -1;
-            }
 
             memcpy(outblob, inblob, sizeof(blob_buffer_t));
             bzero(inblob, sizeof(blob_buffer_t));
@@ -3767,8 +3779,7 @@ static TYPES_INLINE int vutf8_convert(int len, const void *in, int in_len,
 
         /* if the string isn't empty, validate the string and make sure its
          * length matches len (minus 1 for the NUL byte) */
-        if (len > 0 &&
-            (utf8_validate(in, len, &valid_len) || valid_len != len - 1))
+        if (len > 0 && utf8_validate_permitting_trailing_zeros(in, len))
             return -1;
 
         memcpy(out, in, len);
@@ -3785,7 +3796,6 @@ static TYPES_INLINE int vutf8_convert(int len, const void *in, int in_len,
      * fit in the out buffer, then the string needs to be copied from the in
      * buffer to a new out blob */
     else if (len <= in_len) {
-        int valid_len;
 
         if (outblob) {
             if (len > gbl_blob_sz_thresh_bytes)
@@ -3800,8 +3810,7 @@ static TYPES_INLINE int vutf8_convert(int len, const void *in, int in_len,
 
             /* if the string isn't empty, validate the string and make sure its
              * length matches len (minus 1 for the NUL byte) */
-            if (len > 0 &&
-                (utf8_validate(in, len, &valid_len) || valid_len != len - 1))
+            if (len > 0 && utf8_validate_permitting_trailing_zeros(in, len))
                 return -1;
 
             memcpy(outblob->data, in, len);
@@ -3821,8 +3830,6 @@ static TYPES_INLINE int vutf8_convert(int len, const void *in, int in_len,
      * blob to the out buffer */
     else /* len <= out_len */
     {
-        int valid_len;
-
         /* Do not attempt to convert a blob placeholder (i.e., length == -2) */
         if (inblob && inblob->length != OSQL_BLOB_FILLER_LENGTH) {
             if (!inblob->exists || !inblob->data) {
@@ -3832,8 +3839,7 @@ static TYPES_INLINE int vutf8_convert(int len, const void *in, int in_len,
 
             /* if the string isn't empty, validate the string and make sure its
              * length matches len (minus 1 for the NUL byte) */
-            if (len > 0 && (utf8_validate(inblob->data, len, &valid_len) ||
-                            valid_len != len - 1))
+            if (len > 0 && utf8_validate_permitting_trailing_zeros(inblob->data, len))
                 return -1;
 
             memcpy(out, inblob->data, len);

diff --git a/docs/images/alter-table-ddl.gif b/docs/images/alter-table-ddl.gif
diff --git a/docs/images/column-constraint.gif b/docs/images/column-constraint.gif
diff --git a/docs/src/sqlitegen/bubble-generator-data.tcl b/docs/src/sqlitegen/bubble-generator-data.tcl
@@ -724,6 +724,12 @@ stack
           }
       }
       {line OPTION DBPAD = signed-number }
+      {line ENCODING
+          {or
+              {line /string-literal}
+              {line NONE}
+          }
+      }
   }
 
   table-constraint {
@@ -828,6 +834,12 @@ stack
                                           }
                                           NOT NULL
                                       }
+                                      {line ENCODING
+                                          {or
+                                              {line /string-literal}
+                                              {line NONE}
+                                          }
+                                      }
                                   }
                               }
                               {line OPTIONS ( table-options ) }

diff --git a/schemachange/sc_records.c b/schemachange/sc_records.c
@@ -545,12 +545,12 @@ static int prepare_and_verify_newdb_record(struct convert_record_data *data,
     if (rc < 0) {
         logmsg(LOGMSG_DEBUG, "%s:%d internal error during CHECK constraint\n",
                __func__, __LINE__);
-        return ERR_CONSTR;
+        return ERR_CHECK_CONSTRAINT;
     } else if (rc > 0) {
         logmsg(LOGMSG_DEBUG, "%s:%d CHECK constraint failed for '%s'\n",
                __func__, __LINE__,
                data->iq.usedb->check_constraints[rc - 1].consname);
-        return ERR_CONSTR;
+        return ERR_CHECK_CONSTRAINT;
     }
 
     rc = verify_record_constraint(&data->iq, data->to, data->trans, p_buf_data,
@@ -1123,6 +1123,9 @@ static int convert_record(struct convert_record_data *data)
     } else if (rc == ERR_VERIFY_PI) {
         sc_client_error(data->s, "Error verifying partial indexes! rrn %d genid 0x%llx", rrn, genid);
         return -2;
+    } else if (rc == ERR_CHECK_CONSTRAINT) {
+        sc_client_error(data->s, "Record violates check constraints rrn %d genid 0x%llx", rrn, genid);
+        return -2;
     } else if (rc != 0) {
         sc_client_error(data->s,
                         "Error adding record rcode %d opfailcode %d ixfailnum %d rrn %d genid 0x%llx, stripe %d", rc,

diff --git a/sqlite/src/comdb2build.c b/sqlite/src/comdb2build.c
@@ -6406,7 +6406,7 @@ void comdb2DeferForeignKey(Parse *pParse, int isDeferred)
     return;
 }
 
-static void drop_constraint(Parse *pParse, Token *pName, int type)
+static void drop_constraint(Parse *pParse, Token *pName, int type, int hush)
 {
     if (comdb2IsPrepareOnly(pParse))
         return;
@@ -6433,7 +6433,7 @@ static void drop_constraint(Parse *pParse, Token *pName, int type)
     if (cons) {
         /* Mark it as dropped. */
         cons->flags |= CONS_DELETED;
-    } else {
+    } else if (!hush) {
         pParse->rc = SQLITE_ERROR;
         sqlite3ErrorMsg(pParse, "Constraint '%s' not found.", name);
         goto cleanup;
@@ -6454,15 +6454,15 @@ void comdb2DropForeignKey(Parse *pParse, /* Parser context */
                           Token *pName   /* Foreign key name */
 )
 {
-    drop_constraint(pParse, pName, CONS_FKEY);
+    drop_constraint(pParse, pName, CONS_FKEY, 0);
     return;
 }
 
 void comdb2DropConstraint(Parse *pParse, /* Parser context */
                           Token *pName   /* Foreign key name */
 )
 {
-    drop_constraint(pParse, pName, CONS_ALL);
+    drop_constraint(pParse, pName, CONS_ALL, 0);
     return;
 }
 
@@ -7690,3 +7690,65 @@ void create_default_consumer_sp(Parse *p, char *spname)
     comdb2prepareNoRows(v, p, 0, sc, &comdb2SqlSchemaChange, (vdbeFuncArgFree)&free_schema_change_type);
 
 }
+
+void comdb2ChangeCharacterSet(Parse *pParse, Token *t, int alter)
+{
+    struct comdb2_ddl_context *ctx;
+    struct comdb2_column *column;
+    sqlite3 *db = pParse->db;
+
+    char *charset = NULL;
+    char expr[MAXCOLNAME + sizeof("utf8_validate()=0")];
+    char constraint_name[MAXCOLNAME + sizeof("$" GEN_CONS_PREFIX "_CHAR_ENC_")];
+    int nw;
+
+    Token colToken;
+    Token funcToken;
+    ExprList *arg;
+    Expr *func;
+    Expr *zero;
+    Expr *equality;
+
+    if (t != NULL) {
+        charset = sqlite3NameFromToken(db, t);
+        if (charset == NULL)
+            return;
+
+        /* so far only utf8 is supported */
+        if (strcasecmp(charset, "utf8") != 0 && strcasecmp(charset, "utf-8") != 0) {
+            setError(pParse, SQLITE_MISUSE, "unknown charset");
+            goto out;
+        }
+    }
+
+    ctx = pParse->comdb2_ddl_ctx;
+    if (alter)
+        column = ctx->alter_column;
+    else
+        column = (struct comdb2_column *)LISTC_BOT(&ctx->schema->column_list);
+
+    if (column->type != SQL_TYPE_CSTRING && column->type != SQL_TYPE_VARCHAR && column->type != SQL_TYPE_CHAR) {
+        setError(pParse, SQLITE_MISUSE, "invalid column type to use character encoding");
+        goto out;
+    }
+
+    snprintf(constraint_name, sizeof(constraint_name), "$" GEN_CONS_PREFIX "_CHAR_ENC_%s", column->name);
+    sqlite3TokenInit(&pParse->constraintName, constraint_name);
+
+    if (t == NULL) {
+        drop_constraint(pParse, &pParse->constraintName, CONS_CHECK, 1);
+    } else {
+        sqlite3TokenInit(&colToken, column->name);
+        sqlite3TokenInit(&funcToken, "utf8_validate");
+
+        arg = sqlite3ExprListAppend(pParse, NULL, sqlite3ExprAlloc(db, TK_ID, &colToken, 0));
+        func = sqlite3ExprFunction(pParse, arg, &funcToken, 0);
+        zero = sqlite3ExprAlloc(db, TK_INTEGER, &sqlite3IntTokens[0], 0);
+
+        equality = sqlite3PExpr(pParse, TK_EQ, func, zero);
+        nw = snprintf(expr, sizeof(expr), "utf8_validate(%s)=0", column->name);
+        comdb2AddCheckConstraint(pParse, equality, expr, expr + nw + 1);
+    }
+out:
+    sqlite3DbFree(db, charset);
+}
diff --git a/sqlite/src/comdb2build.h b/sqlite/src/comdb2build.h
@@ -80,6 +80,7 @@ void comdb2AddIndex(Parse *, Token *, ExprList *, int, Expr *, const char *,
                     const char *, int, u8, int, ExprList *);
 void comdb2AddDbpad(Parse *, int);
 void comdb2AddCheckConstraint(Parse *, Expr *, const char *, const char *);
+void comdb2ChangeCharacterSet(Parse *pParse, Token *, int);
 void comdb2CreateIndex(Parse *, Token *, Token *, SrcList *, ExprList *, int,
                        Token *, Expr *, const char *, const char *, int, int,
                        u8, int, ExprList *, int);

diff --git a/sqlite/src/func.c b/sqlite/src/func.c
@@ -1418,6 +1418,36 @@ static void uncompressGzipFunc(
     return;
 }
 
+/* Return 0 if payload is utf8. Return (-N - 1), where N is the index
+ * of the first malformed character */
+int utf8_validate(const char *str, int len, int *valid_len);
+static void comdb2Utf8ValidateFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int valid_len, rc, len;
+  const char *z;
+  assert(argc == 1);
+  UNUSED_PARAMETER(argc);
+
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_BLOB:
+      len = sqlite3_value_bytes(argv[0]);
+      z = sqlite3_value_blob(argv[0]);
+      rc = utf8_validate(z, len, &valid_len);
+      break;
+    case SQLITE_TEXT:
+      len = sqlite3_value_bytes(argv[0]) + 1; /* +1 for \0 */
+      z = (const char *)sqlite3_value_text(argv[0]);
+      rc = utf8_validate(z, len, &valid_len);
+      break;
+    default:
+      rc = -1;
+      break;
+  }
+  sqlite3_result_int(context, rc == 0 ? rc : (-valid_len - 1));
+}
 #endif /* defined(SQLITE_BUILDING_FOR_COMDB2) */
 
 /*
@@ -3093,6 +3123,7 @@ void sqlite3RegisterBuiltinFunctions(void){
     FUNCTION(comdb2_starttime,      0, 0, 0, comdb2StartTimeFunc),
     FUNCTION(comdb2_user,           0, 0, 0, comdb2UserFunc),
     FUNCTION(comdb2_last_cost,      0, 0, 0, comdb2LastCostFunc),
+    FUNCTION(utf8_validate,         1, 0, 0, comdb2Utf8ValidateFunc),
     FUNCTION(checksum_md5,          1, 0, 0, md5Func),
     FUNCTION(compress,              1, 0, 0, compressFunc),
     FUNCTION(uncompress,            1, 0, 0, uncompressFunc),

diff --git a/sqlite/src/parse.y b/sqlite/src/parse.y
@@ -542,6 +542,8 @@ ccons ::= PRIMARY KEY sortorder(Z) onconf(R) autoinc(I).
                                  {sqlite3AddPrimaryKey(pParse,0,R,I,Z);}
 %endif !SQLITE_BUILDING_FOR_COMDB2
 %ifdef SQLITE_BUILDING_FOR_COMDB2
+ccons ::= ENCODING STRING(H). {comdb2ChangeCharacterSet(pParse,&H,0);}
+ccons ::= ENCODING NONE. {comdb2ChangeCharacterSet(pParse,NULL,0);}
 ccons ::= UNIQUE onconf(R).      {
     comdb2AddIndex(pParse, 0, 0, R, 0, 0, 0, SQLITE_SO_ASC,
                    SQLITE_IDXTYPE_UNIQUE, 0, 0);
@@ -2037,6 +2039,12 @@ alter_table_alter_column_cmd ::= SET NOT NULL. {
 alter_table_alter_column_cmd ::= DROP NOT NULL. {
   comdb2AlterColumnDropNotNull(pParse);
 }
+alter_table_alter_column_cmd ::= ENCODING STRING(H). {
+  comdb2ChangeCharacterSet(pParse,&H,1);
+}
+alter_table_alter_column_cmd ::= ENCODING NONE. {
+  comdb2ChangeCharacterSet(pParse,NULL,1);
+}
 alter_table_alter_column ::= alter_table_alter_column_start
                              alter_table_alter_column_cmd. {
   comdb2AlterColumnEnd(pParse);

diff --git a/sqlite/tool/mkkeywordhash.c b/sqlite/tool/mkkeywordhash.c
@@ -211,6 +211,7 @@ static Keyword aKeywordTable[] = {
   { "DISTINCT",         "TK_DISTINCT",     ALWAYS                 },
   { "DO",               "TK_DO",           UPSERT                 },
   { "DROP",             "TK_DROP",         ALWAYS                 },
+  { "ENCODING",         "TK_ENCODING",     ALWAYS                 },
   { "END",              "TK_END",          ALWAYS                 },
   { "EACH",             "TK_EACH",         TRIGGER                },
   { "ELSE",             "TK_ELSE",         ALWAYS                 },

diff --git a/tests/auth.test/t09.expected b/tests/auth.test/t09.expected
@@ -65,6 +65,7 @@
 (candidate='EACH')
 (candidate='ELSE')
 (candidate='ENABLE')
+(candidate='ENCODING')
 (candidate='END')
 (candidate='ESCAPE')
 (candidate='EXCEPT')
@@ -377,6 +378,7 @@
 (candidate='unlikely()')
 (candidate='upper()')
 (candidate='usleep()')
+(candidate='utf8_validate()')
 (candidate='zeroblob()')
 (username='user1')
 (username='user2')

diff --git a/tests/comdb2sys.test/comdb2sys.expected b/tests/comdb2sys.test/comdb2sys.expected
@@ -81,9 +81,9 @@
 (tablename='t3', bytes=73728)
 (tablename='t4', bytes=73728)
 [select * from comdb2_tablesizes order by tablename] rc 0
-(KEYWORDS_COUNT=223)
+(KEYWORDS_COUNT=224)
 [SELECT COUNT(*) AS KEYWORDS_COUNT FROM comdb2_keywords] rc 0
-(RESERVED_KW=66)
+(RESERVED_KW=67)
 [SELECT COUNT(*) AS RESERVED_KW FROM comdb2_keywords WHERE reserved = 'Y'] rc 0
 (NONRESERVED_KW=157)
 [SELECT COUNT(*) AS NONRESERVED_KW FROM comdb2_keywords WHERE reserved = 'N'] rc 0
@@ -104,6 +104,7 @@
 (name='DISTINCT', reserved='Y')
 (name='DROP', reserved='Y')
 (name='ELSE', reserved='Y')
+(name='ENCODING', reserved='Y')
 (name='ESCAPE', reserved='Y')
 (name='EXCEPT', reserved='Y')
 (name='EXISTS', reserved='Y')

diff --git a/tests/ddl_no_csc2.test/t09_check.expected b/tests/ddl_no_csc2.test/t09_check.expected
@@ -11,7 +11,7 @@
 ')
 (rows inserted=1)
 (rows inserted=1)
-[ALTER TABLE t1 ADD CONSTRAINT valid_colors CHECK (color IN ('red', 'green', 'blue'))] failed with rc 240 Record violates foreign constraints rrn xx genid xx
+[ALTER TABLE t1 ADD CONSTRAINT valid_colors CHECK (color IN ('red', 'green', 'blue'))] failed with rc 240 Record violates check constraints rrn xx genid xx
 (csc2='schema
 	{
 		cstring color[11] null = yes 

diff --git a/tests/ddl_no_csc2.test/t15_encoding.expected b/tests/ddl_no_csc2.test/t15_encoding.expected
@@ -0,0 +1,17 @@
+[CREATE TABLE t15(a INTEGER ENCODING 'ascii')] failed with rc -3 unknown charset
+[CREATE TABLE t15(a INTEGER ENCODING 'utf8')] failed with rc -3 invalid column type to use character encoding
+[CREATE TABLE t15(a TEXT ENCODING 'utf8')] failed with rc -3 invalid column type to use character encoding
+(csc2='schema
+	{
+		cstring a[11] null = yes 
+	}
+constraints
+	{
+		check "$CONSTRAINT_CHAR_ENC_a" = {where utf8_validate(a)=0}
+	}
+')
+[INSERT INTO t15 VALUES (CAST(x'616263FF616263' AS TEXT))] failed with rc 403 CHECK constraint violation CHECK constraint failed for '$CONSTRAINT_CHAR_ENC_a' unable to add record rc = 320
+(COUNT(*)=0)
+(rows inserted=1)
+(COUNT(*)=1)
+[ALTER TABLE t15 ALTER COLUMN a ENCODING 'utf8'] failed with rc 240 Record violates check constraints rrn xx genid xx