描述
确定当前输入的文本是否似乎形成一个完整的SQL语句，或者在将文本发送到SQLite进行解析之前需要额外的输入。
C / C ++语法
int sqlite3_complete16(const char *sql); |
PB语法
FUNCTION sqlite3_complete16 (BYREF sql AS WSTRINGZ) AS LONG |
参数
sql
[in]要检查的SQL字符串。必须是以本机字节顺序排列的以零终止的UTF-16字符串。
返回值
如果语句不完整，返回0，如果输入字符串看起来是一个完整的SQL语句，则返回1。如果内存分配失败，则返回SQLITE_NOMEM。
备注
Thif函数在命令行输入期间有用，以确定当前输入的文本是否似乎形成完整的SQL语句，或者在将文本发送到SQLite进行解析之前需要额外的输入。如果输入字符串看起来是一个完整的SQL语句，此函数将返回1。如果结尾为分号，并且不是格式正确的CREATE TRIGGER语句的前缀，则判断语句是完整的。嵌入字符串文字或引用的标识符名称或注释中的分号不是独立的标记（它们是嵌入它们的令牌的一部分），因此不会被视为语句终止符。忽略最后一个分号后面的空格和注释。
此函数不解析SQL语句，因此不会检测到语法上不正确的SQL。
如果SQLite在调用sqlite3_complete16之前尚未使用sqlite3_initialize进行初始化，那么sqlite3_initialize将由sqlite3_complete16自动调用。如果该初始化失败，则无论输入SQL是否完整，来自sqlite3_complete16的返回值将不为零。
C ++实现代码
/*
** Return TRUE if the given SQL string ends in a semicolon.
**
** Special handling is require for CREATE TRIGGER statements.
** Whenever the CREATE TRIGGER keywords are seen, the statement
** must end with ";END;".
**
** This implementation uses a state machine with 8 states:
**
** (0) INVALID We have not yet seen a non-whitespace character.
**
** (1) START At the beginning or end of an SQL statement. This function
** returns 1 if it ends in the START state and 0 if it ends
** in any other state.
**
** (2) NORMAL We are in the middle of statement which ends with a single
** semicolon.
**
** (3) EXPLAIN The keyword EXPLAIN has been seen at the beginning of
** a statement.
**
** (4) CREATE The keyword CREATE has been seen at the beginning of a
** statement, possibly preceeded by EXPLAIN and/or followed by
** TEMP or TEMPORARY
**
** (5) TRIGGER We are in the middle of a trigger definition that must be
** ended by a semicolon, the keyword END, and another semicolon.
**
** (6) SEMI We've seen the first semicolon in the ";END;" that occurs at
** the end of a trigger definition.
**
** (7) END We've seen the ";END" of the ";END;" that occurs at the end
** of a trigger difinition.
**
** Transitions between states above are determined by tokens extracted
** from the input. The following tokens are significant:
**
** (0) tkSEMI A semicolon.
** (1) tkWS Whitespace.
** (2) tkOTHER Any other SQL token.
** (3) tkEXPLAIN The "explain" keyword.
** (4) tkCREATE The "create" keyword.
** (5) tkTEMP The "temp" or "temporary" keyword.
** (6) tkTRIGGER The "trigger" keyword.
** (7) tkEND The "end" keyword.
**
** Whitespace never causes a state transition and is always ignored.
** This means that a SQL string of all whitespace is invalid.
**
** If we compile with SQLITE_OMIT_TRIGGER, all of the computation needed
** to recognize the end of a trigger can be omitted. All we have to do
** is look for a semicolon that is not part of an string or comment.
*/
SQLITE_API int sqlite3_complete(const char *zSql){
u8 state = 0; /* Current state, using numbers defined in header comment */
u8 token; /* Value of the next token */
#ifndef SQLITE_OMIT_TRIGGER
/* A complex statement machine used to detect the end of a CREATE TRIGGER
** statement. This is the normal case.
*/
static const u8 trans[8][8] = {
/* Token: */
/* State: ** SEMI WS OTHER EXPLAIN CREATE TEMP TRIGGER END */
/* 0 INVALID: */ { 1, 0, 2, 3, 4, 2, 2, 2, },
/* 1 START: */ { 1, 1, 2, 3, 4, 2, 2, 2, },
/* 2 NORMAL: */ { 1, 2, 2, 2, 2, 2, 2, 2, },
/* 3 EXPLAIN: */ { 1, 3, 3, 2, 4, 2, 2, 2, },
/* 4 CREATE: */ { 1, 4, 2, 2, 2, 4, 5, 2, },
/* 5 TRIGGER: */ { 6, 5, 5, 5, 5, 5, 5, 5, },
/* 6 SEMI: */ { 6, 6, 5, 5, 5, 5, 5, 7, },
/* 7 END: */ { 1, 7, 5, 5, 5, 5, 5, 5, },
};
#else
/* If triggers are not supported by this compile then the statement machine
** used to detect the end of a statement is much simplier
*/
static const u8 trans[3][3] = {
/* Token: */
/* State: ** SEMI WS OTHER */
/* 0 INVALID: */ { 1, 0, 2, },
/* 1 START: */ { 1, 1, 2, },
/* 2 NORMAL: */ { 1, 2, 2, },
};
#endif /* SQLITE_OMIT_TRIGGER */
while( *zSql ){
switch( *zSql ){
case ';': { /* A semicolon */
token = tkSEMI;
break;
}
case ' ':
case '\r':
case '\t':
case '\n':
case '\f': { /* White space is ignored */
token = tkWS;
break;
}
case '/': { /* C-style comments */
if( zSql[1]!='*' ){
token = tkOTHER;
break;
}
zSql += 2;
while( zSql[0] && (zSql[0]!='*' || zSql[1]!='/') ){ zSql++; }
if( zSql[0]==0 ) return 0;
zSql++;
token = tkWS;
break;
}
case '-': { /* SQL-style comments from "--" to end of line */
if( zSql[1]!='-' ){
token = tkOTHER;
break;
}
while( *zSql && *zSql!='\n' ){ zSql++; }
if( *zSql==0 ) return state==1;
token = tkWS;
break;
}
case '[': { /* Microsoft-style identifiers in [...] */
zSql++;
while( *zSql && *zSql!=']' ){ zSql++; }
if( *zSql==0 ) return 0;
token = tkOTHER;
break;
}
case '`': /* Grave-accent quoted symbols used by MySQL */
case '"': /* single- and double-quoted strings */
case '\'': {
int c = *zSql;
zSql++;
while( *zSql && *zSql!=c ){ zSql++; }
if( *zSql==0 ) return 0;
token = tkOTHER;
break;
}
default: {
#ifdef SQLITE_EBCDIC
unsigned char c;
#endif
if( IdChar((u8)*zSql) ){
/* Keywords and unquoted identifiers */
int nId;
for(nId=1; IdChar(zSql[nId]); nId++){}
#ifdef SQLITE_OMIT_TRIGGER
token = tkOTHER;
#else
switch( *zSql ){
case 'c': case 'C': {
if( nId==6 && sqlite3StrNICmp(zSql, "create", 6)==0 ){
token = tkCREATE;
}else{
token = tkOTHER;
}
break;
}
case 't': case 'T': {
if( nId==7 && sqlite3StrNICmp(zSql, "trigger", 7)==0 ){
token = tkTRIGGER;
}else if( nId==4 && sqlite3StrNICmp(zSql, "temp", 4)==0 ){
token = tkTEMP;
}else if( nId==9 && sqlite3StrNICmp(zSql, "temporary", 9)==0 ){
token = tkTEMP;
}else{
token = tkOTHER;
}
break;
}
case 'e': case 'E': {
if( nId==3 && sqlite3StrNICmp(zSql, "end", 3)==0 ){
token = tkEND;
}else
#ifndef SQLITE_OMIT_EXPLAIN
if( nId==7 && sqlite3StrNICmp(zSql, "explain", 7)==0 ){
token = tkEXPLAIN;
}else
#endif
{
token = tkOTHER;
}
break;
}
default: {
token = tkOTHER;
break;
}
}
#endif /* SQLITE_OMIT_TRIGGER */
zSql += nId-1;
}else{
/* Operators and special symbols */
token = tkOTHER;
}
break;
}
}
state = trans[state][token];
zSql++;
}
return state==1;
}
#ifndef SQLITE_OMIT_UTF16
/*
** This function is the same as the sqlite3_complete() function described
** above, except that the parameter is required to be UTF-16 encoded, not
** UTF-8.
*/
SQLITE_API int sqlite3_complete16(const void *zSql){
sqlite3_value *pVal;
char const *zSql8;
int rc = SQLITE_NOMEM;
#ifndef SQLITE_OMIT_AUTOINIT
rc = sqlite3_initialize();
if( rc ) return rc;
#endif
pVal = sqlite3ValueNew(0);
sqlite3ValueSetStr(pVal, -1, zSql, SQLITE_UTF16NATIVE, SQLITE_STATIC);
zSql8 = sqlite3ValueText(pVal, SQLITE_UTF8);
if( zSql8 ){
rc = sqlite3_complete(zSql8);
}else{
rc = SQLITE_NOMEM;
}
sqlite3ValueFree(pVal);
return sqlite3ApiExit(0, rc);
}
#endif /* SQLITE_OMIT_UTF16 */
#endif /* SQLITE_OMIT_COMPLETE */