DaemonService.java

/*
 * Copyright (C) 2008-2009, Google Inc.
 * Copyright (C) 2009, Robin Rosenberg <robin.rosenberg@dewire.com> and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.eclipse.jgit.transport;

import java.io.IOException;
import java.util.Collection;

import org.eclipse.jgit.annotations.Nullable;
import org.eclipse.jgit.lib.Config;
import org.eclipse.jgit.lib.Config.SectionParser;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.transport.resolver.ServiceNotAuthorizedException;
import org.eclipse.jgit.transport.resolver.ServiceNotEnabledException;

/**
 * A service exposed by {@link org.eclipse.jgit.transport.Daemon} over anonymous
 * <code>git://</code>.
 */
public abstract class DaemonService {
    private final String command;

    private final SectionParser<ServiceConfig> configKey;

    private boolean enabled;

    private boolean overridable;

    DaemonService(String cmdName, String cfgName) {
        command = cmdName.startsWith("git-") ? cmdName : "git-" + cmdName; //$NON-NLS-1$ //$NON-NLS-2$
        configKey = cfg -> new ServiceConfig(DaemonService.this, cfg, cfgName);
        overridable = true;
    }

    private static class ServiceConfig {
        final boolean enabled;

        ServiceConfig(final DaemonService service, final Config cfg,
                final String name) {
            enabled = cfg.getBoolean("daemon", name, service.isEnabled()); //$NON-NLS-1$
        }
    }

    /**
     * Whether this service is enabled for invocation.
     *
     * @return whether this service is enabled for invocation.
     */
    public boolean isEnabled() {
        return enabled;
    }

    /**
     * Set if it is allowed to use this service
     *
     * @param on
     *            {@code true} to allow this service to be used; {@code false}
     *            to deny it.
     */
    public void setEnabled(boolean on) {
        enabled = on;
    }

    /** @return can this service be configured in the repository config file? */
    /**
     * Whether this service can be configured in the repository config file
     *
     * @return whether this service can be configured in the repository config
     *         file
     */
    public boolean isOverridable() {
        return overridable;
    }

    /**
     * Whether to permit repositories to override this service's enabled state
     * with the <code>daemon.servicename</code> config setting.
     *
     * @param on
     *            {@code true} to permit repositories to override this service's
     *            enabled state with the <code>daemon.servicename</code> config
     *            setting.
     */
    public void setOverridable(boolean on) {
        overridable = on;
    }

    /**
     * Get name of the command requested by clients.
     *
     * @return name of the command requested by clients.
     */
    public String getCommandName() {
        return command;
    }

    /**
     * Determine if this service can handle the requested command.
     *
     * @param commandLine
     *            input line from the client.
     * @return true if this command can accept the given command line.
     */
    public boolean handles(String commandLine) {
        return command.length() + 1 < commandLine.length()
                && commandLine.charAt(command.length()) == ' '
                && commandLine.startsWith(command);
    }

    void execute(DaemonClient client, String commandLine,
            @Nullable Collection<String> extraParameters)
            throws IOException, ServiceNotEnabledException,
            ServiceNotAuthorizedException {
        final String name = commandLine.substring(command.length() + 1);
        try (Repository db = client.getDaemon().openRepository(client, name)) {
            if (isEnabledFor(db)) {
                execute(client, db, extraParameters);
            }
        } catch (ServiceMayNotContinueException e) {
            // An error when opening the repo means the client is expecting a ref
            // advertisement, so use that style of error.
            PacketLineOut pktOut = new PacketLineOut(client.getOutputStream());
            pktOut.writeString("ERR " + e.getMessage() + "\n"); //$NON-NLS-1$ //$NON-NLS-2$
        }
    }

    private boolean isEnabledFor(Repository db) {
        if (isOverridable())
            return db.getConfig().get(configKey).enabled;
        return isEnabled();
    }

    abstract void execute(DaemonClient client, Repository db,
            @Nullable Collection<String> extraParameters)
            throws IOException, ServiceNotEnabledException,
            ServiceNotAuthorizedException;
}