/**
* Algorithm of Tarjan for computing the strongly connected components of a graph.
*
* @param v current node
* @throws QueryException if a variable directly calls itself
*/
private void tarjan(final int v) throws QueryException {
final int ixv = 2 * v, llv = ixv + 1, idx = next++;
while (list.size() <= llv) list.add(-1);
list.set(ixv, idx);
list.set(llv, idx);
stack.push(v);
for (final int w : adjacentTo(v)) {
final int ixw = 2 * w, llw = ixw + 1;
if (list.size() <= ixw || list.get(ixw) < 0) {
// Successor w has not yet been visited; recurse on it
tarjan(w);
list.set(llv, Math.min(list.get(llv), list.get(llw)));
} else if (stack.contains(w)) {
// Successor w is in stack S and hence in the current SCC
list.set(llv, Math.min(list.get(llv), list.get(ixw)));
}
}
// If v is a root node, pop the stack and generate an SCC
if (list.get(llv) == list.get(ixv)) {
int w;
Scope[] out = null;
do {
w = stack.pop();
final Scope scp = scopes.get(w);
out = out == null ? new Scope[] {scp} : Array.add(out, scp);
} while (w != v);
result.add(out);
}
}
/**
* Inserts a data instance at the specified pre value. Note that the specified data instance must
* differ from this instance.
*
* @param ipre value at which to insert new data
* @param ipar parent pre value of node
* @param clip data clip
*/
public final void insert(final int ipre, final int ipar, final DataClip clip) {
meta.update();
// update value and document indexes
if (meta.updindex) indexBegin();
resources.insert(ipre, clip);
final int dsize = clip.size();
final int buf = Math.min(dsize, IO.BLOCKSIZE >> IO.NODEPOWER);
// resize buffer to cache more entries
buffer(buf);
// find all namespaces in scope to avoid duplicate declarations
final TokenMap nsScope = nspaces.scope(ipar, this);
// loop through all entries
final IntList preStack = new IntList();
final NSNode nsRoot = nspaces.current();
final HashSet<NSNode> newNodes = new HashSet<NSNode>();
final IntList flagPres = new IntList();
// indicates if database only contains a dummy node
final Data data = clip.data;
int c = 0;
for (int dpre = clip.start; dpre < clip.end; ++dpre, ++c) {
if (c != 0 && c % buf == 0) insert(ipre + c - buf);
final int pre = ipre + c;
final int dkind = data.kind(dpre);
final int dpar = data.parent(dpre, dkind);
// ipar < 0 if document nodes on top level are added
final int dis = dpar >= 0 ? dpre - dpar : ipar >= 0 ? pre - ipar : 0;
final int par = dis == 0 ? -1 : pre - dis;
if (c == 0) nspaces.root(par, this);
while (!preStack.isEmpty() && preStack.peek() > par) nspaces.close(preStack.pop());
switch (dkind) {
case DOC:
// add document
nspaces.prepare();
final int s = data.size(dpre, dkind);
doc(pre, s, data.text(dpre, true));
meta.ndocs++;
preStack.push(pre);
break;
case ELEM:
// add element
nspaces.prepare();
boolean ne = false;
if (data.nsFlag(dpre)) {
final Atts at = data.ns(dpre);
for (int a = 0; a < at.size(); ++a) {
// see if prefix has been declared/ is part of current ns scope
final byte[] old = nsScope.get(at.name(a));
if (old == null || !eq(old, at.value(a))) {
// we have to keep track of all new NSNodes that are added
// to the Namespace structure, as their pre values must not
// be updated. I.e. if an NSNode N with pre value 3 existed
// prior to inserting and two new nodes are inserted at
// location pre == 3 we have to make sure N and only N gets
// updated.
newNodes.add(nspaces.add(at.name(a), at.value(a), pre));
ne = true;
}
}
}
byte[] nm = data.name(dpre, dkind);
elem(
dis,
tagindex.index(nm, null, false),
data.attSize(dpre, dkind),
data.size(dpre, dkind),
nspaces.uri(nm, true),
ne);
preStack.push(pre);
break;
case TEXT:
case COMM:
case PI:
// add text
text(pre, dis, data.text(dpre, true), dkind);
break;
case ATTR:
// add attribute
nm = data.name(dpre, dkind);
// check if prefix already in nsScope or not
final byte[] attPref = prefix(nm);
// check if prefix of attribute has already been declared, otherwise
// add declaration to parent node
if (data.nsFlag(dpre) && nsScope.get(attPref) == null) {
nspaces.add(
par,
preStack.isEmpty() ? -1 : preStack.peek(),
attPref,
data.nspaces.uri(data.uri(dpre, dkind)),
this);
// save pre value to set ns flag later for this node. can't be done
// here as direct table access would interfere with the buffer
flagPres.add(par);
}
attr(
pre,
dis,
atnindex.index(nm, null, false),
data.text(dpre, false),
nspaces.uri(nm, false),
false);
break;
}
}
// finalize and update namespace structure
while (!preStack.isEmpty()) nspaces.close(preStack.pop());
nspaces.root(nsRoot);
if (bp != 0) insert(ipre + c - 1 - (c - 1) % buf);
// reset buffer to old size
buffer(1);
// set ns flags
for (int f = 0; f < flagPres.size(); f++) {
final int fl = flagPres.get(f);
table.write2(fl, 1, name(fl) | 1 << 15);
}
// increase size of ancestors
int p = ipar;
while (p >= 0) {
final int k = kind(p);
size(p, k, size(p, k) + dsize);
p = parent(p, k);
}
if (meta.updindex) {
// add the entries to the ID -> PRE mapping:
idmap.insert(ipre, id(ipre), dsize);
indexEnd();
}
if (!cache) updateDist(ipre + dsize, dsize);
// propagate PRE value shifts to namespaces
if (ipar != -1) nspaces.insert(ipre, dsize, newNodes);
}
/**
* Optimizes the structures of a database.
*
* @param data data
* @param enforceText enforce creation or deletion of text index
* @param enforceAttr enforce creation or deletion of attribute index
* @param enforceToken enforce creation or deletion of token index
* @param enforceFt enforce creation or deletion of full-text index
* @param cmd calling command instance (may be {@code null})
* @throws IOException I/O Exception during index rebuild
*/
public static void optimize(
final Data data,
final boolean enforceText,
final boolean enforceAttr,
final boolean enforceToken,
final boolean enforceFt,
final Optimize cmd)
throws IOException {
// initialize structural indexes
final MetaData md = data.meta;
if (!md.uptodate) {
data.paths.init();
data.elemNames.init();
data.attrNames.init();
md.dirty = true;
final IntList pars = new IntList(), elms = new IntList();
int n = 0;
for (int pre = 0; pre < md.size; ++pre) {
final byte kind = (byte) data.kind(pre);
final int par = data.parent(pre, kind);
while (!pars.isEmpty() && pars.peek() > par) {
pars.pop();
elms.pop();
}
final int level = pars.size();
if (kind == Data.DOC) {
data.paths.put(0, Data.DOC, level);
pars.push(pre);
elms.push(0);
++n;
} else if (kind == Data.ELEM) {
final int id = data.nameId(pre);
data.elemNames.index(data.elemNames.key(id), null, true);
data.paths.put(id, Data.ELEM, level);
pars.push(pre);
elms.push(id);
} else if (kind == Data.ATTR) {
final int id = data.nameId(pre);
final byte[] val = data.text(pre, false);
data.attrNames.index(data.attrNames.key(id), val, true);
data.paths.put(id, Data.ATTR, level, val, md);
} else {
final byte[] val = data.text(pre, true);
if (kind == Data.TEXT && level > 1) data.elemNames.index(elms.peek(), val);
data.paths.put(0, kind, level, val, md);
}
if (cmd != null) cmd.pre = pre;
}
md.ndocs = n;
md.uptodate = true;
}
// rebuild value indexes
optimize(IndexType.TEXT, data, md.createtext, md.textindex, enforceText, cmd);
optimize(IndexType.ATTRIBUTE, data, md.createattr, md.attrindex, enforceAttr, cmd);
optimize(IndexType.TOKEN, data, md.createtoken, md.tokenindex, enforceToken, cmd);
optimize(IndexType.FULLTEXT, data, md.createft, md.ftindex, enforceFt, cmd);
}