btdump.cc

btdump.cc

#include <libcouchstore/couch_db.h>
#include "internal.h"
#include <stdio.h>
#include <vector>
#include <stdlib.h>
#include "util.h"
#include "couch_btree.h"
#include "bitfield.h"
#include <iostream>
#include <numeric>

using std::vector;
using std::cout;
using std::endl;
using std::cerr;

void error_die(couchstore_error_t err) {
    if(err == COUCHSTORE_SUCCESS) {
        return;
    }

    fprintf(stderr, "Couchstore error: %s\n", couchstore_strerror(err));
    exit(1);
}
vector<int> leafdepths;

couchstore_error_t dump_node(uint64_t diskpos, Db* db, uint64_t parent, int i, int depth) {
    int bufpos = 1, nodebuflen = 0;
    int count = 0;

    couchstore_error_t errcode = COUCHSTORE_SUCCESS;

    char *nodebuf = NULL;

    nodebuflen = pread_compressed(db, diskpos, &nodebuf);
    if(nodebuflen < 0) {
        errcode = (couchstore_error_t) nodebuflen;
        goto cleanup;
    }

    if (nodebuf[0] == 0) { //KP Node
        while (bufpos < nodebuflen) {
            uint32_t klen, vlen;
            get_kvlen(nodebuf + bufpos, &klen, &vlen);
            sized_buf cmp_key = {nodebuf + bufpos + 5, klen};
            sized_buf val_buf = {nodebuf + bufpos + 5 + klen, vlen};
            bufpos += 5 + klen + vlen;

            uint64_t pointer = 0;
            //Descend into the pointed to node.
            pointer = get_48(val_buf.buf);
            error_pass(dump_node(pointer, db, diskpos, count, depth + 1));
            count ++;
        }
        cout << "node" << diskpos << "[label = \"KP\"];" << endl;
    } else if (nodebuf[0] == 1) { //KV Node
        while (bufpos < nodebuflen) {
            uint32_t klen, vlen;
            get_kvlen(nodebuf + bufpos, &klen, &vlen);
            sized_buf cmp_key = {nodebuf + bufpos + 5, klen};
            sized_buf val_buf = {nodebuf + bufpos + 5 + klen, vlen};
            bufpos += 5 + klen + vlen;
            //Leaf found
            count ++;
            leafdepths.push_back(depth);
        }
        cout << "node" << diskpos << "[label = \"";
        cout << count << " KVs\"];" << endl;
    }
    if(parent) {
        cout << "\"node" << parent << "\" -> \"node" << diskpos
             << "\";" << endl;
    }
cleanup:
    free(nodebuf);
    return errcode;
}

double mean(const vector<int> &list) {
    return std::accumulate(list.begin(), list.end(), 0.0) / list.size();
}

int main(int argc, char** argv) {
    Db *db;
    couchstore_error_t errcode;

    errcode = couchstore_open_db(argv[1], 0, &db);
    error_die(errcode);

    node_pointer* bt_ex = NULL;
    if(argv[2][0] == 's') {
        bt_ex = db->header.by_seq_root;
    }
    if(argv[2][0] == 'i') {
        bt_ex = db->header.by_id_root;
    }
    if(argv[2][0] == 'l') {
        bt_ex = db->header.local_docs_root;
    }
    if(bt_ex == NULL) {
        fprintf(stderr, "What btree?\n");
        exit(1);
    }
    cout << "digraph g {" << endl;
    cout << "node [shape = record, height=.1];" << endl;
    dump_node(bt_ex->pointer, db, 0, 0, 0);
    cout << "}" << endl;
    cerr << "Mean leaf depth: " << mean(leafdepths) << endl;
}