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libsql/libsql-sqlite3/ext/misc/dbdump.c
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/*
** 2016-03-13
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file implements a C-language subroutine that converts the content
** of an SQLite database into UTF-8 text SQL statements that can be used
** to exactly recreate the original database. ROWID values are preserved.
**
** A prototype of the implemented subroutine is this:
**
** int sqlite3_db_dump(
** sqlite3 *db,
** const char *zSchema,
** const char *zTable,
** void (*xCallback)(void*, const char*),
** void *pArg
** );
**
** The db parameter is the database connection. zSchema is the schema within
** that database which is to be dumped. Usually the zSchema is "main" but
** can also be "temp" or any ATTACH-ed database. If zTable is not NULL, then
** only the content of that one table is dumped. If zTable is NULL, then all
** tables are dumped.
**
** The generate text is passed to xCallback() in multiple calls. The second
** argument to xCallback() is a copy of the pArg parameter. The first
** argument is some of the output text that this routine generates. The
** signature to xCallback() is designed to make it compatible with fputs().
**
** The sqlite3_db_dump() subroutine returns SQLITE_OK on success or some error
** code if it encounters a problem.
**
** If this file is compiled with -DDBDUMP_STANDALONE then a "main()" routine
** is included so that this routine becomes a command-line utility. The
** command-line utility takes two or three arguments which are the name
** of the database file, the schema, and optionally the table, forming the
** first three arguments of a single call to the library routine.
*/
#include "sqlite3.h"
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
/*
** The state of the dump process.
*/
typedef struct DState DState;
struct DState {
sqlite3 *db; /* The database connection */
int nErr; /* Number of errors seen so far */
int rc; /* Error code */
int writableSchema; /* True if in writable_schema mode */
int (*xCallback)(const char*,void*); /* Send output here */
void *pArg; /* Argument to xCallback() */
};
/*
** A variable length string to which one can append text.
*/
typedef struct DText DText;
struct DText {
char *z; /* The text */
int n; /* Number of bytes of content in z[] */
int nAlloc; /* Number of bytes allocated to z[] */
};
/*
** Initialize and destroy a DText object
*/
static void initText(DText *p){
memset(p, 0, sizeof(*p));
}
static void freeText(DText *p){
sqlite3_free(p->z);
initText(p);
}
/* zIn is either a pointer to a NULL-terminated string in memory obtained
** from malloc(), or a NULL pointer. The string pointed to by zAppend is
** added to zIn, and the result returned in memory obtained from malloc().
** zIn, if it was not NULL, is freed.
**
** If the third argument, quote, is not '\0', then it is used as a
** quote character for zAppend.
*/
static void appendText(DText *p, char const *zAppend, char quote){
int len;
int i;
int nAppend = (int)(strlen(zAppend) & 0x3fffffff);
len = nAppend+p->n+1;
if( quote ){
len += 2;
for(i=0; i<nAppend; i++){
if( zAppend[i]==quote ) len++;
}
}
if( p->n+len>=p->nAlloc ){
char *zNew;
p->nAlloc = p->nAlloc*2 + len + 20;
zNew = sqlite3_realloc(p->z, p->nAlloc);
if( zNew==0 ){
freeText(p);
return;
}
p->z = zNew;
}
if( quote ){
char *zCsr = p->z+p->n;
*zCsr++ = quote;
for(i=0; i<nAppend; i++){
*zCsr++ = zAppend[i];
if( zAppend[i]==quote ) *zCsr++ = quote;
}
*zCsr++ = quote;
p->n = (int)(zCsr - p->z);
*zCsr = '\0';
}else{
memcpy(p->z+p->n, zAppend, nAppend);
p->n += nAppend;
p->z[p->n] = '\0';
}
}
/*
** Attempt to determine if identifier zName needs to be quoted, either
** because it contains non-alphanumeric characters, or because it is an
** SQLite keyword. Be conservative in this estimate: When in doubt assume
** that quoting is required.
**
** Return '"' if quoting is required. Return 0 if no quoting is required.
*/
static char quoteChar(const char *zName){
int i;
if( !isalpha((unsigned char)zName[0]) && zName[0]!='_' ) return '"';
for(i=0; zName[i]; i++){
if( !isalnum((unsigned char)zName[i]) && zName[i]!='_' ) return '"';
}
return sqlite3_keyword_check(zName, i) ? '"' : 0;
}
/*
** Release memory previously allocated by tableColumnList().
*/
static void freeColumnList(char **azCol){
int i;
for(i=1; azCol[i]; i++){
sqlite3_free(azCol[i]);
}
/* azCol[0] is a static string */
sqlite3_free(azCol);
}
/*
** Return a list of pointers to strings which are the names of all
** columns in table zTab. The memory to hold the names is dynamically
** allocated and must be released by the caller using a subsequent call
** to freeColumnList().
**
** The azCol[0] entry is usually NULL. However, if zTab contains a rowid
** value that needs to be preserved, then azCol[0] is filled in with the
** name of the rowid column.
**
** The first regular column in the table is azCol[1]. The list is terminated
** by an entry with azCol[i]==0.
*/
static char **tableColumnList(DState *p, const char *zTab){
char **azCol = 0;
sqlite3_stmt *pStmt = 0;
char *zSql;
int nCol = 0;
int nAlloc = 0;
int nPK = 0; /* Number of PRIMARY KEY columns seen */
int isIPK = 0; /* True if one PRIMARY KEY column of type INTEGER */
int preserveRowid = 1;
int rc;
zSql = sqlite3_mprintf("PRAGMA table_info=%Q", zTab);
if( zSql==0 ) return 0;
rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
sqlite3_free(zSql);
if( rc ) return 0;
while( sqlite3_step(pStmt)==SQLITE_ROW ){
if( nCol>=nAlloc-2 ){
char **azNew;
nAlloc = nAlloc*2 + nCol + 10;
azNew = sqlite3_realloc64(azCol, nAlloc*sizeof(azCol[0]));
if( azNew==0 ) goto col_oom;
azCol = azNew;
azCol[0] = 0;
}
azCol[++nCol] = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 1));
if( azCol[nCol]==0 ) goto col_oom;
if( sqlite3_column_int(pStmt, 5) ){
nPK++;
if( nPK==1
&& sqlite3_stricmp((const char*)sqlite3_column_text(pStmt,2),
"INTEGER")==0
){
isIPK = 1;
}else{
isIPK = 0;
}
}
}
sqlite3_finalize(pStmt);
pStmt = 0;
azCol[nCol+1] = 0;
/* The decision of whether or not a rowid really needs to be preserved
** is tricky. We never need to preserve a rowid for a WITHOUT ROWID table
** or a table with an INTEGER PRIMARY KEY. We are unable to preserve
** rowids on tables where the rowid is inaccessible because there are other
** columns in the table named "rowid", "_rowid_", and "oid".
*/
if( isIPK ){
/* If a single PRIMARY KEY column with type INTEGER was seen, then it
** might be an alise for the ROWID. But it might also be a WITHOUT ROWID
** table or a INTEGER PRIMARY KEY DESC column, neither of which are
** ROWID aliases. To distinguish these cases, check to see if
** there is a "pk" entry in "PRAGMA index_list". There will be
** no "pk" index if the PRIMARY KEY really is an alias for the ROWID.
*/
zSql = sqlite3_mprintf("SELECT 1 FROM pragma_index_list(%Q)"
" WHERE origin='pk'", zTab);
if( zSql==0 ) goto col_oom;
rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
sqlite3_free(zSql);
if( rc ){
freeColumnList(azCol);
return 0;
}
rc = sqlite3_step(pStmt);
sqlite3_finalize(pStmt);
pStmt = 0;
preserveRowid = rc==SQLITE_ROW;
}
if( preserveRowid ){
/* Only preserve the rowid if we can find a name to use for the
** rowid */
static char *azRowid[] = { "rowid", "_rowid_", "oid" };
int i, j;
for(j=0; j<3; j++){
for(i=1; i<=nCol; i++){
if( sqlite3_stricmp(azRowid[j],azCol[i])==0 ) break;
}
if( i>nCol ){
/* At this point, we know that azRowid[j] is not the name of any
** ordinary column in the table. Verify that azRowid[j] is a valid
** name for the rowid before adding it to azCol[0]. WITHOUT ROWID
** tables will fail this last check */
rc = sqlite3_table_column_metadata(p->db,0,zTab,azRowid[j],0,0,0,0,0);
if( rc==SQLITE_OK ) azCol[0] = azRowid[j];
break;
}
}
}
return azCol;
col_oom:
sqlite3_finalize(pStmt);
freeColumnList(azCol);
p->nErr++;
p->rc = SQLITE_NOMEM;
return 0;
}
/*
** Send mprintf-formatted content to the output callback.
*/
static void output_formatted(DState *p, const char *zFormat, ...){
va_list ap;
char *z;
va_start(ap, zFormat);
z = sqlite3_vmprintf(zFormat, ap);
va_end(ap);
p->xCallback(z, p->pArg);
sqlite3_free(z);
}
/*
** Find a string that is not found anywhere in z[]. Return a pointer
** to that string.
**
** Try to use zA and zB first. If both of those are already found in z[]
** then make up some string and store it in the buffer zBuf.
*/
static const char *unused_string(
const char *z, /* Result must not appear anywhere in z */
const char *zA, const char *zB, /* Try these first */
char *zBuf /* Space to store a generated string */
){
unsigned i = 0;
if( strstr(z, zA)==0 ) return zA;
if( strstr(z, zB)==0 ) return zB;
do{
sqlite3_snprintf(20,zBuf,"(%s%u)", zA, i++);
}while( strstr(z,zBuf)!=0 );
return zBuf;
}
/*
** Output the given string as a quoted string using SQL quoting conventions.
** Additionallly , escape the "\n" and "\r" characters so that they do not
** get corrupted by end-of-line translation facilities in some operating
** systems.
*/
static void output_quoted_escaped_string(DState *p, const char *z){
int i;
char c;
for(i=0; (c = z[i])!=0 && c!='\'' && c!='\n' && c!='\r'; i++){}
if( c==0 ){
output_formatted(p,"'%s'",z);
}else{
const char *zNL = 0;
const char *zCR = 0;
int nNL = 0;
int nCR = 0;
char zBuf1[20], zBuf2[20];
for(i=0; z[i]; i++){
if( z[i]=='\n' ) nNL++;
if( z[i]=='\r' ) nCR++;
}
if( nNL ){
p->xCallback("replace(", p->pArg);
zNL = unused_string(z, "\\n", "\\012", zBuf1);
}
if( nCR ){
p->xCallback("replace(", p->pArg);
zCR = unused_string(z, "\\r", "\\015", zBuf2);
}
p->xCallback("'", p->pArg);
while( *z ){
for(i=0; (c = z[i])!=0 && c!='\n' && c!='\r' && c!='\''; i++){}
if( c=='\'' ) i++;
if( i ){
output_formatted(p, "%.*s", i, z);
z += i;
}
if( c=='\'' ){
p->xCallback("'", p->pArg);
continue;
}
if( c==0 ){
break;
}
z++;
if( c=='\n' ){
p->xCallback(zNL, p->pArg);
continue;
}
p->xCallback(zCR, p->pArg);
}
p->xCallback("'", p->pArg);
if( nCR ){
output_formatted(p, ",'%s',char(13))", zCR);
}
if( nNL ){
output_formatted(p, ",'%s',char(10))", zNL);
}
}
}
/*
** This is an sqlite3_exec callback routine used for dumping the database.
** Each row received by this callback consists of a table name,
** the table type ("index" or "table") and SQL to create the table.
** This routine should print text sufficient to recreate the table.
*/
static int dump_callback(void *pArg, int nArg, char **azArg, char **azCol){
int rc;
const char *zTable;
const char *zType;
const char *zSql;
DState *p = (DState*)pArg;
sqlite3_stmt *pStmt;
(void)azCol;
if( nArg!=3 ) return 1;
zTable = azArg[0];
zType = azArg[1];
zSql = azArg[2];
if( strcmp(zTable, "sqlite_sequence")==0 ){
p->xCallback("DELETE FROM sqlite_sequence;\n", p->pArg);
}else if( sqlite3_strglob("sqlite_stat?", zTable)==0 ){
p->xCallback("ANALYZE sqlite_schema;\n", p->pArg);
}else if( strncmp(zTable, "sqlite_", 7)==0 ){
return 0;
}else if( strncmp(zSql, "CREATE VIRTUAL TABLE", 20)==0 ){
if( !p->writableSchema ){
p->xCallback("PRAGMA writable_schema=ON;\n", p->pArg);
p->writableSchema = 1;
}
output_formatted(p,
"INSERT INTO sqlite_schema(type,name,tbl_name,rootpage,sql)"
"VALUES('table','%q','%q',0,'%q');",
zTable, zTable, zSql);
return 0;
}else{
if( sqlite3_strglob("CREATE TABLE ['\"]*", zSql)==0 ){
p->xCallback("CREATE TABLE IF NOT EXISTS ", p->pArg);
p->xCallback(zSql+13, p->pArg);
}else{
p->xCallback(zSql, p->pArg);
}
p->xCallback(";\n", p->pArg);
}
if( strcmp(zType, "table")==0 ){
DText sSelect;
DText sTable;
char **azTCol;
int i;
int nCol;
azTCol = tableColumnList(p, zTable);
if( azTCol==0 ) return 0;
initText(&sTable);
appendText(&sTable, "INSERT INTO ", 0);
/* Always quote the table name, even if it appears to be pure ascii,
** in case it is a keyword. Ex: INSERT INTO "table" ... */
appendText(&sTable, zTable, quoteChar(zTable));
/* If preserving the rowid, add a column list after the table name.
** In other words: "INSERT INTO tab(rowid,a,b,c,...) VALUES(...)"
** instead of the usual "INSERT INTO tab VALUES(...)".
*/
if( azTCol[0] ){
appendText(&sTable, "(", 0);
appendText(&sTable, azTCol[0], 0);
for(i=1; azTCol[i]; i++){
appendText(&sTable, ",", 0);
appendText(&sTable, azTCol[i], quoteChar(azTCol[i]));
}
appendText(&sTable, ")", 0);
}
appendText(&sTable, " VALUES(", 0);
/* Build an appropriate SELECT statement */
initText(&sSelect);
appendText(&sSelect, "SELECT ", 0);
if( azTCol[0] ){
appendText(&sSelect, azTCol[0], 0);
appendText(&sSelect, ",", 0);
}
for(i=1; azTCol[i]; i++){
appendText(&sSelect, azTCol[i], quoteChar(azTCol[i]));
if( azTCol[i+1] ){
appendText(&sSelect, ",", 0);
}
}
nCol = i;
if( azTCol[0]==0 ) nCol--;
freeColumnList(azTCol);
appendText(&sSelect, " FROM ", 0);
appendText(&sSelect, zTable, quoteChar(zTable));
rc = sqlite3_prepare_v2(p->db, sSelect.z, -1, &pStmt, 0);
if( rc!=SQLITE_OK ){
p->nErr++;
if( p->rc==SQLITE_OK ) p->rc = rc;
}else{
while( SQLITE_ROW==sqlite3_step(pStmt) ){
p->xCallback(sTable.z, p->pArg);
for(i=0; i<nCol; i++){
if( i ) p->xCallback(",", p->pArg);
switch( sqlite3_column_type(pStmt,i) ){
case SQLITE_INTEGER: {
output_formatted(p, "%lld", sqlite3_column_int64(pStmt,i));
break;
}
case SQLITE_FLOAT: {
double r = sqlite3_column_double(pStmt,i);
sqlite3_uint64 ur;
memcpy(&ur,&r,sizeof(r));
if( ur==0x7ff0000000000000LL ){
p->xCallback("1e999", p->pArg);
}else if( ur==0xfff0000000000000LL ){
p->xCallback("-1e999", p->pArg);
}else{
output_formatted(p, "%!.20g", r);
}
break;
}
case SQLITE_NULL: {
p->xCallback("NULL", p->pArg);
break;
}
case SQLITE_TEXT: {
output_quoted_escaped_string(p,
(const char*)sqlite3_column_text(pStmt,i));
break;
}
case SQLITE_BLOB: {
int nByte = sqlite3_column_bytes(pStmt,i);
unsigned char *a = (unsigned char*)sqlite3_column_blob(pStmt,i);
int j;
p->xCallback("x'", p->pArg);
for(j=0; j<nByte; j++){
char zWord[3];
zWord[0] = "0123456789abcdef"[(a[j]>>4)&15];
zWord[1] = "0123456789abcdef"[a[j]&15];
zWord[2] = 0;
p->xCallback(zWord, p->pArg);
}
p->xCallback("'", p->pArg);
break;
}
}
}
p->xCallback(");\n", p->pArg);
}
}
sqlite3_finalize(pStmt);
freeText(&sTable);
freeText(&sSelect);
}
return 0;
}
/*
** Execute a query statement that will generate SQL output. Print
** the result columns, comma-separated, on a line and then add a
** semicolon terminator to the end of that line.
**
** If the number of columns is 1 and that column contains text "--"
** then write the semicolon on a separate line. That way, if a
** "--" comment occurs at the end of the statement, the comment
** won't consume the semicolon terminator.
*/
static void output_sql_from_query(
DState *p, /* Query context */
const char *zSelect, /* SELECT statement to extract content */
...
){
sqlite3_stmt *pSelect;
int rc;
int nResult;
int i;
const char *z;
char *zSql;
va_list ap;
va_start(ap, zSelect);
zSql = sqlite3_vmprintf(zSelect, ap);
va_end(ap);
if( zSql==0 ){
p->rc = SQLITE_NOMEM;
p->nErr++;
return;
}
rc = sqlite3_prepare_v2(p->db, zSql, -1, &pSelect, 0);
sqlite3_free(zSql);
if( rc!=SQLITE_OK || !pSelect ){
output_formatted(p, "/**** ERROR: (%d) %s *****/\n", rc,
sqlite3_errmsg(p->db));
p->nErr++;
return;
}
rc = sqlite3_step(pSelect);
nResult = sqlite3_column_count(pSelect);
while( rc==SQLITE_ROW ){
z = (const char*)sqlite3_column_text(pSelect, 0);
p->xCallback(z, p->pArg);
for(i=1; i<nResult; i++){
p->xCallback(",", p->pArg);
p->xCallback((const char*)sqlite3_column_text(pSelect,i), p->pArg);
}
if( z==0 ) z = "";
while( z[0] && (z[0]!='-' || z[1]!='-') ) z++;
if( z[0] ){
p->xCallback("\n;\n", p->pArg);
}else{
p->xCallback(";\n", p->pArg);
}
rc = sqlite3_step(pSelect);
}
rc = sqlite3_finalize(pSelect);
if( rc!=SQLITE_OK ){
output_formatted(p, "/**** ERROR: (%d) %s *****/\n", rc,
sqlite3_errmsg(p->db));
if( (rc&0xff)!=SQLITE_CORRUPT ) p->nErr++;
}
}
/*
** Run zQuery. Use dump_callback() as the callback routine so that
** the contents of the query are output as SQL statements.
**
** If we get a SQLITE_CORRUPT error, rerun the query after appending
** "ORDER BY rowid DESC" to the end.
*/
static void run_schema_dump_query(
DState *p,
const char *zQuery,
...
){
char *zErr = 0;
char *z;
va_list ap;
va_start(ap, zQuery);
z = sqlite3_vmprintf(zQuery, ap);
va_end(ap);
sqlite3_exec(p->db, z, dump_callback, p, &zErr);
sqlite3_free(z);
if( zErr ){
output_formatted(p, "/****** %s ******/\n", zErr);
sqlite3_free(zErr);
p->nErr++;
zErr = 0;
}
}
/*
** Convert an SQLite database into SQL statements that will recreate that
** database.
*/
int sqlite3_db_dump(
sqlite3 *db, /* The database connection */
const char *zSchema, /* Which schema to dump. Usually "main". */
const char *zTable, /* Which table to dump. NULL means everything. */
int (*xCallback)(const char*,void*), /* Output sent to this callback */
void *pArg /* Second argument of the callback */
){
DState x;
memset(&x, 0, sizeof(x));
x.rc = sqlite3_exec(db, "BEGIN", 0, 0, 0);
if( x.rc ) return x.rc;
x.db = db;
x.xCallback = xCallback;
x.pArg = pArg;
xCallback("PRAGMA foreign_keys=OFF;\nBEGIN TRANSACTION;\n", pArg);
if( zTable==0 ){
run_schema_dump_query(&x,
"SELECT name, type, sql FROM \"%w\".sqlite_schema "
"WHERE sql NOT NULL AND type=='table' AND name!='sqlite_sequence'",
zSchema
);
run_schema_dump_query(&x,
"SELECT name, type, sql FROM \"%w\".sqlite_schema "
"WHERE name=='sqlite_sequence'", zSchema
);
output_sql_from_query(&x,
"SELECT sql FROM sqlite_schema "
"WHERE sql NOT NULL AND type IN ('index','trigger','view')", 0
);
}else{
run_schema_dump_query(&x,
"SELECT name, type, sql FROM \"%w\".sqlite_schema "
"WHERE tbl_name=%Q COLLATE nocase AND type=='table'"
" AND sql NOT NULL",
zSchema, zTable
);
output_sql_from_query(&x,
"SELECT sql FROM \"%w\".sqlite_schema "
"WHERE sql NOT NULL"
" AND type IN ('index','trigger','view')"
" AND tbl_name=%Q COLLATE nocase",
zSchema, zTable
);
}
if( x.writableSchema ){
xCallback("PRAGMA writable_schema=OFF;\n", pArg);
}
xCallback(x.nErr ? "ROLLBACK; -- due to errors\n" : "COMMIT;\n", pArg);
sqlite3_exec(db, "COMMIT", 0, 0, 0);
return x.rc;
}
/* The generic subroutine is above. The code the follows implements
** the command-line interface.
*/
#ifdef DBDUMP_STANDALONE
#include <stdio.h>
/*
** Command-line interface
*/
int main(int argc, char **argv){
sqlite3 *db;
const char *zDb;
const char *zSchema;
const char *zTable = 0;
int rc;
if( argc<2 || argc>4 ){
fprintf(stderr, "Usage: %s DATABASE ?SCHEMA? ?TABLE?\n", argv[0]);
return 1;
}
zDb = argv[1];
zSchema = argc>=3 ? argv[2] : "main";
zTable = argc==4 ? argv[3] : 0;
rc = sqlite3_open(zDb, &db);
if( rc ){
fprintf(stderr, "Cannot open \"%s\": %s\n", zDb, sqlite3_errmsg(db));
sqlite3_close(db);
return 1;
}
rc = sqlite3_db_dump(db, zSchema, zTable,
(int(*)(const char*,void*))fputs, (void*)stdout);
if( rc ){
fprintf(stderr, "Error: sqlite3_db_dump() returns %d\n", rc);
}
sqlite3_close(db);
return rc!=SQLITE_OK;
}
#endif /* DBDUMP_STANDALONE */
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