Digikam-FatClient/offline/pgfutils/digikam_extract_thumbs.cpp

#include "pgfutils.h"
#include "sqlite3.h"

#include <iostream>
#include <memory>
#include <sstream>
#include <exception>

void usage() {
    std::cerr << "Usage: digikam_extract_thumbs /path/to/thumbnails-digikam.db /path/to/output/folder\n";
}

sqlite3* open_db(std::string path) {
    sqlite3 *db;
    if(auto retval = sqlite3_open(path.c_str(), &db)) {
        std::ostringstream s;
        s << "Can't open database " << path << ": " << sqlite3_errmsg(db) << std::endl;
        throw std::runtime_error(s.str());
    }
    return db;
}

int main(int argc, char* argv[]) {
    if(argc != 3) {
        std::cerr << "Incorrect amount of arguments.\n";
        usage();
        exit(1);
    }

    std::string sqlite_path(argv[1]);
    std::string output_path(argv[2]);

    auto db = open_db(sqlite_path);

    std::string query = "SELECT UniqueHashes.uniqueHash, Thumbnails.data FROM Thumbnails INNER JOIN UniqueHashes ON Thumbnails.id=UniqueHashes.thumbId;";

    sqlite3_stmt *stmt;
    sqlite3_prepare_v2(db, query.c_str(), query.length(), &stmt, 0);
    int result = sqlite3_step(stmt);
    int i = 0;
    while(result == SQLITE_ROW) {
        const std::string unique_hash((const char*)sqlite3_column_text(stmt, 0));
        int size = sqlite3_column_bytes(stmt, 1);
        const char* data_start = static_cast<const char*>(sqlite3_column_blob(stmt, 1));
        const char* data_end = data_start + size;
        //std::vector<char> data(data_start, data_end);
        QByteArray qdata(data_start, size);
        QImage thumb;
        if(readPGFImageData(qdata, thumb, false)) {
            auto filename = output_path + "/" + unique_hash + ".jpg";
            //std::cout << i << ": " << unique_hash << ": " << size << " bytes -> " << filename << std::endl;
            thumb.save(QString::fromStdString(filename));
        } else {
            throw std::runtime_error("Failed to read PGF image.\n");
        }

        result = sqlite3_step(stmt);
        i++;

        if(i % 100 == 0) {
            std::cout << i << "\n";
        }
    }

    std::cout << "Done (" << i << " total)\n";
    sqlite3_close(db);
}