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/** @file glass_values.h
* @brief GlassValueManager class
*/
/* Copyright (C) 2008,2009,2011 Olly Betts
* Copyright (C) 2008 Lemur Consulting Ltd
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef XAPIAN_INCLUDED_GLASS_VALUES_H
#define XAPIAN_INCLUDED_GLASS_VALUES_H
#include "pack.h"
#include "backends/valuestats.h"
#include "xapian/error.h"
#include "xapian/types.h"
#include "autoptr.h"
#include <map>
#include <string>
class GlassCursor;
namespace Glass {
/** Generate a key for a value stream chunk. */
inline std::string
make_valuechunk_key(Xapian::valueno slot, Xapian::docid did)
{
std::string key("\0\xd8", 2);
pack_uint(key, slot);
pack_uint_preserving_sort(key, did);
return key;
}
inline Xapian::docid
docid_from_key(Xapian::valueno required_slot, const std::string & key)
{
const char * p = key.data();
const char * end = p + key.length();
// Fail if not a value chunk key.
if (end - p < 2 || *p++ != '\0' || *p++ != '\xd8') return 0;
Xapian::valueno slot;
if (!unpack_uint(&p, end, &slot))
throw Xapian::DatabaseCorruptError("bad value key");
// Fail if for a different slot.
if (slot != required_slot) return 0;
Xapian::docid did;
if (!unpack_uint_preserving_sort(&p, end, &did))
throw Xapian::DatabaseCorruptError("bad value key");
return did;
}
}
namespace Xapian {
class Document;
}
class GlassPostListTable;
class GlassTermListTable;
struct ValueStats;
class GlassValueManager {
/** The value number for the most recently used value statistics.
*
* Set to Xapian::BAD_VALUENO if no value statistics are currently
* cached.
*/
mutable Xapian::valueno mru_slot;
/** The most recently used value statistics. */
mutable ValueStats mru_valstats;
GlassPostListTable * postlist_table;
GlassTermListTable * termlist_table;
std::map<Xapian::docid, std::string> slots;
std::map<Xapian::valueno, std::map<Xapian::docid, std::string> > changes;
mutable AutoPtr<GlassCursor> cursor;
void add_value(Xapian::docid did, Xapian::valueno slot,
const std::string & val);
void remove_value(Xapian::docid did, Xapian::valueno slot);
Xapian::docid get_chunk_containing_did(Xapian::valueno slot,
Xapian::docid did,
std::string &chunk) const;
/** Get the statistics for value slot @a slot. */
void get_value_stats(Xapian::valueno slot) const;
void get_value_stats(Xapian::valueno slot, ValueStats & stats) const;
public:
/** Create a new GlassValueManager object. */
GlassValueManager(GlassPostListTable * postlist_table_,
GlassTermListTable * termlist_table_)
: mru_slot(Xapian::BAD_VALUENO),
postlist_table(postlist_table_),
termlist_table(termlist_table_) { }
// Merge in batched-up changes.
void merge_changes();
void add_document(Xapian::docid did, const Xapian::Document &doc,
std::map<Xapian::valueno, ValueStats> & value_stats);
void delete_document(Xapian::docid did,
std::map<Xapian::valueno, ValueStats> & value_stats);
void replace_document(Xapian::docid did, const Xapian::Document &doc,
std::map<Xapian::valueno, ValueStats> & value_stats);
std::string get_value(Xapian::docid did, Xapian::valueno slot) const;
void get_all_values(std::map<Xapian::valueno, std::string> & values,
Xapian::docid did) const;
Xapian::doccount get_value_freq(Xapian::valueno slot) const {
if (mru_slot != slot) get_value_stats(slot);
return mru_valstats.freq;
}
std::string get_value_lower_bound(Xapian::valueno slot) const {
if (mru_slot != slot) get_value_stats(slot);
return mru_valstats.lower_bound;
}
std::string get_value_upper_bound(Xapian::valueno slot) const {
if (mru_slot != slot) get_value_stats(slot);
return mru_valstats.upper_bound;
}
/** Write the updated statistics to the table.
*
* If the @a freq member of the statistics for a particular slot is 0, the
* statistics for that slot will be cleared.
*
* @param value_stats The statistics to set.
*/
void set_value_stats(std::map<Xapian::valueno, ValueStats> & value_stats);
void reset() {
/// Ignore any old cached valuestats.
mru_slot = Xapian::BAD_VALUENO;
}
bool is_modified() const {
return !changes.empty();
}
void cancel() {
// Discard batched-up changes.
slots.clear();
changes.clear();
}
};
namespace Glass {
class ValueChunkReader {
const char *p;
const char *end;
Xapian::docid did;
std::string value;
public:
/// Create a ValueChunkReader which is already at_end().
ValueChunkReader() : p(NULL) { }
ValueChunkReader(const char * p_, size_t len, Xapian::docid did_) {
assign(p_, len, did_);
}
void assign(const char * p_, size_t len, Xapian::docid did_);
bool at_end() const { return p == NULL; }
Xapian::docid get_docid() const { return did; }
const std::string & get_value() const { return value; }
void next();
void skip_to(Xapian::docid target);
};
}
#endif // XAPIAN_INCLUDED_GLASS_VALUES_H
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