/*
** 2019-01-21
**
** 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 an extension that uses the SQLITE_CONFIG_MALLOC
** mechanism to add a tracing layer on top of SQLite. If this extension
** is registered prior to sqlite3_initialize(), it will cause all memory
** allocation activities to be logged on standard output, or to some other
** FILE specified by the initializer.
**
** This file needs to be compiled into the application that uses it.
**
** This extension is used to implement the --memtrace option of the
** command-line shell.
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>
/* The original memory allocation routines */
static sqlite3_mem_methods memtraceBase;
static FILE *memtraceOut;
/* Methods that trace memory allocations */
static void *memtraceMalloc(int n){
if( memtraceOut ){
fprintf(memtraceOut, "MEMTRACE: allocate %d bytes\n",
memtraceBase.xRoundup(n));
}
return memtraceBase.xMalloc(n);
}
static void memtraceFree(void *p){
if( p==0 ) return;
if( memtraceOut ){
fprintf(memtraceOut, "MEMTRACE: free %d bytes\n", memtraceBase.xSize(p));
}
memtraceBase.xFree(p);
}
static void *memtraceRealloc(void *p, int n){
if( p==0 ) return memtraceMalloc(n);
if( n==0 ){
memtraceFree(p);
return 0;
}
if( memtraceOut ){
fprintf(memtraceOut, "MEMTRACE: resize %d -> %d bytes\n",
memtraceBase.xSize(p), memtraceBase.xRoundup(n));
}
return memtraceBase.xRealloc(p, n);
}
static int memtraceSize(void *p){
return memtraceBase.xSize(p);
}
static int memtraceRoundup(int n){
return memtraceBase.xRoundup(n);
}
static int memtraceInit(void *p){
return memtraceBase.xInit(p);
}
static void memtraceShutdown(void *p){
memtraceBase.xShutdown(p);
}
/* The substitute memory allocator */
static sqlite3_mem_methods ersaztMethods = {
memtraceMalloc,
memtraceFree,
memtraceRealloc,
memtraceSize,
memtraceRoundup,
memtraceInit,
memtraceShutdown,
0
};
/* Begin tracing memory allocations to out. */
int sqlite3MemTraceActivate(FILE *out){
int rc = SQLITE_OK;
if( memtraceBase.xMalloc==0 ){
rc = sqlite3_config(SQLITE_CONFIG_GETMALLOC, &memtraceBase);
if( rc==SQLITE_OK ){
rc = sqlite3_config(SQLITE_CONFIG_MALLOC, &ersaztMethods);
}
}
memtraceOut = out;
return rc;
}
/* Deactivate memory tracing */
int sqlite3MemTraceDeactivate(void){
int rc = SQLITE_OK;
if( memtraceBase.xMalloc!=0 ){
rc = sqlite3_config(SQLITE_CONFIG_MALLOC, &memtraceBase);
if( rc==SQLITE_OK ){
memset(&memtraceBase, 0, sizeof(memtraceBase));
}
}
memtraceOut = 0;
return rc;
}