/*
** Copyright (c) 2011 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the Simplified BSD License (also
** known as the "2-Clause License" or "FreeBSD License".)
** This program is distributed in the hope that it will be useful,
** but without any warranty; without even the implied warranty of
** merchantability or fitness for a particular purpose.
**
** Author contact information:
** drh@sqlite.org
**
*******************************************************************************
**
** This file contains code used to trace paths of through the
** directed acyclic graph (DAG) of checkins.
*/
#include "config.h"
#include "path.h"
#include <assert.h>
#if INTERFACE
/* Nodes for the paths through the DAG.
*/
struct PathNode {
int rid; /* ID for this node */
u8 fromIsParent; /* True if pFrom is the parent of rid */
u8 isPrim; /* True if primary side of common ancestor */
PathNode *pFrom; /* Node we came from */
union {
PathNode *pPeer; /* List of nodes of the same generation */
PathNode *pTo; /* Next on path from beginning to end */
} u;
PathNode *pAll; /* List of all nodes */
};
#endif
/*
** Local variables for this module
*/
static struct {
PathNode *pCurrent; /* Current generation of nodes */
PathNode *pAll; /* All nodes */
Bag seen; /* Nodes seen before */
int nStep; /* Number of steps from first to last */
PathNode *pStart; /* Earliest node */
PathNode *pPivot; /* Common ancestor of pStart and pEnd */
PathNode *pEnd; /* Most recent */
} path;
/*
** Return the first (last) element of the computed path.
*/
PathNode *path_first(void){ return path.pStart; }
PathNode *path_last(void){ return path.pEnd; }
/*
** Return the number of steps in the computed path.
*/
int path_length(void){ return path.nStep; }
/*
** Create a new node
*/
static PathNode *path_new_node(int rid, PathNode *pFrom, int isParent){
PathNode *p;
p = fossil_malloc( sizeof(*p) );
memset(p, 0, sizeof(*p));
p->rid = rid;
p->fromIsParent = isParent;
p->pFrom = pFrom;
p->u.pPeer = path.pCurrent;
path.pCurrent = p;
p->pAll = path.pAll;
path.pAll = p;
bag_insert(&path.seen, rid);
return p;
}
/*
** Reset memory used by the shortest path algorithm.
*/
void path_reset(void){
PathNode *p;
while( path.pAll ){
p = path.pAll;
path.pAll = p->pAll;
fossil_free(p);
}
bag_clear(&path.seen);
path.pCurrent = 0;
path.pAll = 0;
path.pEnd = 0;
path.nStep = 0;
}
/*
** Construct the path from path.pStart to path.pEnd in the u.pTo fields.
*/
void path_reverse_path(void){
PathNode *p;
for(p=path.pEnd; p && p->pFrom; p = p->pFrom){
p->pFrom->u.pTo = p;
}
path.pEnd->u.pTo = 0;
assert( p==path.pStart );
}
/*
** Compute the shortest path from iFrom to iTo
**
** If directOnly is true, then use only the "primary" links from parent to
** child. In other words, ignore merges.
**
** Return a pointer to the beginning of the path (the iFrom node).
** Elements of the path can be traversed by following the PathNode.u.pTo
** pointer chain.
**
** Return NULL if no path is found.
*/
PathNode *path_shortest(int iFrom, int iTo, int directOnly){
Stmt s;
PathNode *pPrev;
PathNode *p;
path_reset();
path.pStart = path_new_node(iFrom, 0, 0);
if( iTo==iFrom ){
path.pEnd = path.pStart;
return path.pStart;
}
if( directOnly ){
db_prepare(&s,
"SELECT cid, 1 FROM plink WHERE pid=:pid AND isprim "
"UNION ALL "
"SELECT pid, 0 FROM plink WHERE cid=:pid AND isprim"
);
}else{
db_prepare(&s,
"SELECT cid, 1 FROM plink WHERE pid=:pid "
"UNION ALL "
"SELECT pid, 0 FROM plink WHERE cid=:pid"
);
}
while( path.pCurrent ){
path.nStep++;
pPrev = path.pCurrent;
path.pCurrent = 0;
while( pPrev ){
db_bind_int(&s, ":pid", pPrev->rid);
while( db_step(&s)==SQLITE_ROW ){
int cid = db_column_int(&s, 0);
int isParent = db_column_int(&s, 1);
if( bag_find(&path.seen, cid) ) continue;
p = path_new_node(cid, pPrev, isParent);
if( cid==iTo ){
db_finalize(&s);
path.pEnd = p;
path_reverse_path();
return path.pStart;
}
}
db_reset(&s);
pPrev = pPrev->u.pPeer;
}
}
db_finalize(&s);
path_reset();
return 0;
}
/*
** Find the mid-point of the path. If the path contains fewer than
** 2 steps, return 0.
*/
PathNode *path_midpoint(void){
PathNode *p;
int i;
if( path.nStep<2 ) return 0;
for(p=path.pEnd, i=0; p && i<path.nStep/2; p=p->pFrom, i++){}
return p;
}
/*
** COMMAND: test-shortest-path
**
** Usage: %fossil test-shortest-path ?--no-merge? VERSION1 VERSION2
**
** Report the shortest path between two checkins. If the --no-merge flag
** is used, follow only direct parent-child paths and omit merge links.
*/
void shortest_path_test_cmd(void){
int iFrom;
int iTo;
PathNode *p;
int n;
int directOnly;
db_find_and_open_repository(0,0);
directOnly = find_option("no-merge",0,0)!=0;
if( g.argc!=4 ) usage("VERSION1 VERSION2");
iFrom = name_to_rid(g.argv[2]);
iTo = name_to_rid(g.argv[3]);
p = path_shortest(iFrom, iTo, directOnly);
if( p==0 ){
fossil_fatal("no path from %s to %s", g.argv[1], g.argv[2]);
}
for(n=1, p=path.pStart; p; p=p->u.pTo, n++){
char *z;
z = db_text(0,
"SELECT substr(uuid,1,12) || ' ' || datetime(mtime)"
" FROM blob, event"
" WHERE blob.rid=%d AND event.objid=%d AND event.type='ci'",
p->rid, p->rid);
fossil_print("%4d: %s", n, z);
fossil_free(z);
if( p->u.pTo ){
fossil_print(" is a %s of\n",
p->u.pTo->fromIsParent ? "parent" : "child");
}else{
fossil_print("\n");
}
}
}
/*
** Find the closest common ancestor of two nodes. "Closest" means the
** fewest number of arcs.
*/
int path_common_ancestor(int iMe, int iYou){
Stmt s;
PathNode *pPrev;
PathNode *p;
Bag me, you;
if( iMe==iYou ) return iMe;
if( iMe==0 || iYou==0 ) return 0;
path_reset();
path.pStart = path_new_node(iMe, 0, 0);
path.pStart->isPrim = 1;
path.pEnd = path_new_node(iYou, 0, 0);
db_prepare(&s, "SELECT pid FROM plink WHERE cid=:cid");
bag_init(&me);
bag_insert(&me, iMe);
bag_init(&you);
bag_insert(&you, iYou);
while( path.pCurrent ){
pPrev = path.pCurrent;
path.pCurrent = 0;
while( pPrev ){
db_bind_int(&s, ":cid", pPrev->rid);
while( db_step(&s)==SQLITE_ROW ){
int pid = db_column_int(&s, 0);
if( bag_find(pPrev->isPrim ? &you : &me, pid) ){
/* pid is the common ancestor */
PathNode *pNext;
for(p=path.pAll; p && p->rid!=pid; p=p->pAll){}
assert( p!=0 );
pNext = p;
while( pNext ){
pNext = p->pFrom;
p->pFrom = pPrev;
pPrev = p;
p = pNext;
}
if( pPrev==path.pStart ) path.pStart = path.pEnd;
path.pEnd = pPrev;
path_reverse_path();
db_finalize(&s);
return pid;
}else if( bag_find(&path.seen, pid) ){
/* pid is just an alternative path on one of the legs */
continue;
}
p = path_new_node(pid, pPrev, 0);
p->isPrim = pPrev->isPrim;
bag_insert(pPrev->isPrim ? &me : &you, pid);
}
db_reset(&s);
pPrev = pPrev->u.pPeer;
}
}
db_finalize(&s);
path_reset();
return 0;
}
/*
** COMMAND: test-ancestor-path
**
** Usage: %fossil test-ancestor-path VERSION1 VERSION2
**
** Report the path from VERSION1 to VERSION2 through their most recent
** common ancestor.
*/
void ancestor_path_test_cmd(void){
int iFrom;
int iTo;
int iPivot;
PathNode *p;
int n;
db_find_and_open_repository(0,0);
if( g.argc!=4 ) usage("VERSION1 VERSION2");
iFrom = name_to_rid(g.argv[2]);
iTo = name_to_rid(g.argv[3]);
iPivot = path_common_ancestor(iFrom, iTo);
for(n=1, p=path.pStart; p; p=p->u.pTo, n++){
char *z;
z = db_text(0,
"SELECT substr(uuid,1,12) || ' ' || datetime(mtime)"
" FROM blob, event"
" WHERE blob.rid=%d AND event.objid=%d AND event.type='ci'",
p->rid, p->rid);
fossil_print("%4d: %s", n, z);
fossil_free(z);
if( p->rid==iFrom ) fossil_print(" VERSION1");
if( p->rid==iTo ) fossil_print(" VERSION2");
if( p->rid==iPivot ) fossil_print(" PIVOT");
fossil_print("\n");
}
}
/*
** A record of a file rename operation.
*/
typedef struct NameChange NameChange;
struct NameChange {
int origName; /* Original name of file */
int curName; /* Current name of the file */
int newName; /* Name of file in next version */
NameChange *pNext; /* List of all name changes */
};
/*
** Compute all file name changes that occur going from checkin iFrom
** to checkin iTo.
**
** The number of name changes is written into *pnChng. For each name
** change, two integers are allocated for *piChng. The first is the
** filename.fnid for the original name and the second is for new name.
** Space to hold *piChng is obtained from fossil_malloc() and should
** be released by the caller.
**
** This routine really has nothing to do with pathion. It is located
** in this path.c module in order to leverage some of the path
** infrastructure.
*/
void find_filename_changes(
int iFrom,
int iTo,
int *pnChng,
int **aiChng
){
PathNode *p; /* For looping over path from iFrom to iTo */
NameChange *pAll = 0; /* List of all name changes seen so far */
NameChange *pChng; /* For looping through the name change list */
int nChng = 0; /* Number of files whose names have changed */
int *aChng; /* Two integers per name change */
int i; /* Loop counter */
Stmt q1; /* Query of name changes */
*pnChng = 0;
*aiChng = 0;
if( iFrom==iTo ) return;
path_reset();
p = path_shortest(iFrom, iTo, 0);
if( p==0 ) return;
path_reverse_path();
db_prepare(&q1,
"SELECT pfnid, fnid FROM mlink WHERE mid=:mid AND pfnid>0"
);
for(p=path.pStart; p; p=p->u.pTo){
int fnid, pfnid;
if( !p->fromIsParent && (p->u.pTo==0 || p->u.pTo->fromIsParent) ){
/* Skip nodes where the parent is not on the path */
continue;
}
db_bind_int(&q1, ":mid", p->rid);
while( db_step(&q1)==SQLITE_ROW ){
if( p->fromIsParent ){
fnid = db_column_int(&q1, 1);
pfnid = db_column_int(&q1, 0);
}else{
fnid = db_column_int(&q1, 0);
pfnid = db_column_int(&q1, 1);
}
for(pChng=pAll; pChng; pChng=pChng->pNext){
if( pChng->curName==pfnid ){
pChng->newName = fnid;
break;
}
}
if( pChng==0 ){
pChng = fossil_malloc( sizeof(*pChng) );
pChng->pNext = pAll;
pAll = pChng;
pChng->origName = pfnid;
pChng->curName = pfnid;
pChng->newName = fnid;
nChng++;
}
}
for(pChng=pAll; pChng; pChng=pChng->pNext) pChng->curName = pChng->newName;
db_reset(&q1);
}
db_finalize(&q1);
if( nChng ){
*pnChng = nChng;
aChng = *aiChng = fossil_malloc( nChng*2*sizeof(int) );
for(pChng=pAll, i=0; pChng; pChng=pChng->pNext, i+=2){
aChng[i] = pChng->origName;
aChng[i+1] = pChng->newName;
}
while( pAll ){
pChng = pAll;
pAll = pAll->pNext;
fossil_free(pChng);
}
}
}
/*
** COMMAND: test-name-changes
**
** Usage: %fossil test-name-changes VERSION1 VERSION2
**
** Show all filename changes that occur going from VERSION1 to VERSION2
*/
void test_name_change(void){
int iFrom;
int iTo;
int *aChng;
int nChng;
int i;
db_find_and_open_repository(0,0);
if( g.argc!=4 ) usage("VERSION1 VERSION2");
iFrom = name_to_rid(g.argv[2]);
iTo = name_to_rid(g.argv[3]);
find_filename_changes(iFrom, iTo, &nChng, &aChng);
for(i=0; i<nChng; i++){
char *zFrom, *zTo;
zFrom = db_text(0, "SELECT name FROM filename WHERE fnid=%d", aChng[i*2]);
zTo = db_text(0, "SELECT name FROM filename WHERE fnid=%d", aChng[i*2+1]);
fossil_print("[%s] -> [%s]\n", zFrom, zTo);
fossil_free(zFrom);
fossil_free(zTo);
}
fossil_free(aChng);
}