annotate bits/PluginHandleMapper.h @ 60:8a4bcb3dc3a6

Replace exceptions throughout the JSON-handling and adapter code with string-arg error handling. No longer need exception handling enabled in Emscripten (with its consequent runtime overhead - though we still need to check whether this error handling regime is actually faster).

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Vampipe

    Centre for Digital Music, Queen Mary, University of London.
    Copyright 2006-2016 Chris Cannam and QMUL.
  
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*/

#ifndef VAMPIPE_PLUGIN_HANDLE_MAPPER_H
#define VAMPIPE_PLUGIN_HANDLE_MAPPER_H

#include "PluginOutputIdMapper.h"

#include <vamp-hostsdk/Plugin.h>
#include <memory>

namespace vampipe {

/**
 * Convert plugin pointers to handles within some scope defined by the
 * individual PluginHandleMapper implementation.
 *
 * The special handle 0 and the NULL plugin pointer are both used to
 * represent "not found" and will be returned in any case where an
 * unknown handle or plugin is requested.
 *
 * Note that the handle type must be representable as a JSON number,
 * hence the use of a 32-bit rather than 64-bit int.
 *
 * This interface also includes methods for obtaining a
 * PluginOutputIdMapper, \see PluginOutputIdMapper.
 */

class PluginHandleMapper
{
public:
    typedef int32_t Handle;
    const Handle INVALID_HANDLE = 0;

    virtual ~PluginHandleMapper() noexcept { }

    /**
     * Look up and return the handle for a given plugin pointer.
     * If the given pointer is null or not known, return INVALID_HANDLE.
     */
    virtual Handle pluginToHandle(Vamp::Plugin *) const noexcept = 0;

    /**
     * Look up and return the plugin for a given handle.
     * If the given handle is INVALID_HANDLE or not known, return nullptr.
     */
    virtual Vamp::Plugin *handleToPlugin(Handle)  const noexcept = 0;

    /**
     * Return a shared pointer to a PluginOutputIdMapper
     * implementation for the given plugin pointer.  If the given
     * pointer is null or not known, return the null shared_ptr.
     */
    virtual const std::shared_ptr<PluginOutputIdMapper> pluginToOutputIdMapper
    (Vamp::Plugin *p) const noexcept = 0;

    /**
     * Return a shared pointer to a PluginOutputIdMapper
     * implementation for the given plugin handle.  If the given
     * handle is INVALID_HANDLE or not known, return the null shared_ptr.
     */
    virtual const std::shared_ptr<PluginOutputIdMapper> handleToOutputIdMapper
    (Handle h) const noexcept = 0;
};

}

#endif