/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim:set ts=4 sw=4 sts=4 et: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"

interface nsICancelable;
interface nsIProtocolProxyCallback;
interface nsIProtocolProxyFilter;
interface nsIProxyInfo;
interface nsIChannel;
interface nsIURI;

/**
 * nsIProtocolProxyService provides methods to access information about
 * various network proxies.
 */
[scriptable, uuid(e77c642b-026f-41ce-9b23-f829a6e3f300)]
interface nsIProtocolProxyService : nsISupports
{
    /** Flag 1 << 0 is unused **/

    /**
     * When the proxy configuration is manual this flag may be passed to the
     * resolve and asyncResolve methods to request to prefer the SOCKS proxy
     * to HTTP ones.
     */
    const unsigned long RESOLVE_PREFER_SOCKS_PROXY = 1 << 1;

    /**
     * When the proxy configuration is manual this flag may be passed to the
     * resolve and asyncResolve methods to request to not analyze the uri's
     * scheme specific proxy. When this flag is set the main HTTP proxy is the
     * preferred one.
     *
     * NOTE: if RESOLVE_PREFER_SOCKS_PROXY is set then the SOCKS proxy is
     *       the preferred one.
     *
     * NOTE: if RESOLVE_PREFER_HTTPS_PROXY is set then the HTTPS proxy
     *       is the preferred one.
     */
    const unsigned long RESOLVE_IGNORE_URI_SCHEME = 1 << 2;

    /**
     * When the proxy configuration is manual this flag may be passed to the
     * resolve and asyncResolve methods to request to prefer the HTTPS proxy
     * to the others HTTP ones.
     *
     * NOTE: RESOLVE_PREFER_SOCKS_PROXY takes precedence over this flag.
     *
     * NOTE: This flag implies RESOLVE_IGNORE_URI_SCHEME.
     */
    const unsigned long RESOLVE_PREFER_HTTPS_PROXY =
        (1 << 3) | RESOLVE_IGNORE_URI_SCHEME;

    /**
     * When the proxy configuration is manual this flag may be passed to the
     * resolve and asyncResolve methods to that all methods will be tunneled via
     * CONNECT through the http proxy.
     */
    const unsigned long RESOLVE_ALWAYS_TUNNEL = (1 << 4);

    /**
     * This method returns via callback a nsIProxyInfo instance that identifies
     * a proxy to be used for loading the given URI.  Otherwise, this method returns
     * null indicating that a direct connection should be used.
     *
     * @param aURI
     *        The URI to test.
     * @param aFlags
     *        A bit-wise combination of the RESOLVE_ flags defined above.  Pass
     *        0 to specify the default behavior.  Any additional bits that do
     *        not correspond to a RESOLVE_ flag are reserved for future use.
     * @param aCallback
     *        The object to be notified when the result is available.
     *
     * @return An object that can be used to cancel the asychronous operation.
     *         If canceled, the cancelation status (aReason) will be forwarded
     *         to the callback's onProxyAvailable method via the aStatus param.
     *
     * NOTE: If this proxy is unavailable, getFailoverForProxy may be called
     * to determine the correct secondary proxy to be used.
     *
     * NOTE: If the protocol handler for the given URI supports
     * nsIProxiedProtocolHandler, then the nsIProxyInfo instance returned from
     * resolve may be passed to the newProxiedChannel method to create a
     * nsIChannel to the given URI that uses the specified proxy.
     *
     * NOTE: However, if the nsIProxyInfo type is "http", then it means that
     * the given URI should be loaded using the HTTP protocol handler, which
     * also supports nsIProxiedProtocolHandler.
     *
     * @see nsIProxiedProtocolHandler::newProxiedChannel 
     */
    nsICancelable asyncResolve(in nsIURI aURI, in unsigned long aFlags,
                               in nsIProtocolProxyCallback aCallback);

    /**
     * This method may be called to construct a nsIProxyInfo instance from
     * the given parameters.  This method may be useful in conjunction with
     * nsISocketTransportService::createTransport for creating, for example,
     * a SOCKS connection.
     *
     * @param aType
     *        The proxy type.  This is a string value that identifies the proxy
     *        type.  Standard values include:
     *          "http"    - specifies a HTTP proxy
     *          "socks"   - specifies a SOCKS version 5 proxy
     *          "socks4"  - specifies a SOCKS version 4 proxy
     *          "direct"  - specifies a direct connection (useful for failover)
     *        The type name is case-insensitive.  Other string values may be
     *        possible, and new types may be defined by a future version of
     *        this interface.
     * @param aHost
     *        The proxy hostname or IP address.
     * @param aPort
     *        The proxy port.
     * @param aFlags
     *        Flags associated with this connection.  See nsIProxyInfo.idl
     *        for currently defined flags.
     * @param aFailoverTimeout
     *        Specifies the length of time (in seconds) to ignore this proxy if
     *        this proxy fails.  Pass UINT32_MAX to specify the default
     *        timeout value, causing nsIProxyInfo::failoverTimeout to be
     *        assigned the default value.
     * @param aFailoverProxy
     *        Specifies the next proxy to try if this proxy fails.  This
     *        parameter may be null.
     */
    nsIProxyInfo newProxyInfo(in ACString aType, in AUTF8String aHost,
                              in long aPort, in unsigned long aFlags,
                              in unsigned long aFailoverTimeout,
                              in nsIProxyInfo aFailoverProxy);

    /**
     * If the proxy identified by aProxyInfo is unavailable for some reason,
     * this method may be called to access an alternate proxy that may be used
     * instead.  As a side-effect, this method may affect future result values
     * from resolve/asyncResolve as well as from getFailoverForProxy.
     *
     * @param aProxyInfo
     *        The proxy that was unavailable.
     * @param aURI
     *        The URI that was originally passed to resolve/asyncResolve.
     * @param aReason
     *        The error code corresponding to the proxy failure.  This value
     *        may be used to tune the delay before this proxy is used again.
     *
     * @throw NS_ERROR_NOT_AVAILABLE if there is no alternate proxy available.
     */
    nsIProxyInfo getFailoverForProxy(in nsIProxyInfo aProxyInfo,
                                     in nsIURI       aURI,
                                     in nsresult     aReason);

    /**
     * This method may be used to register a proxy filter instance.  Each proxy
     * filter is registered with an associated position that determines the
     * order in which the filters are applied (starting from position 0).  When
     * resolve/asyncResolve is called, it generates a list of proxies for the
     * given URI, and then it applies the proxy filters.  The filters have the
     * opportunity to modify the list of proxies.
     *
     * If two filters register for the same position, then the filters will be
     * visited in the order in which they were registered.
     *
     * If the filter is already registered, then its position will be updated.
     *
     * After filters have been run, any disabled or disallowed proxies will be
     * removed from the list.  A proxy is disabled if it had previously failed-
     * over to another proxy (see getFailoverForProxy).  A proxy is disallowed,
     * for example, if it is a HTTP proxy and the nsIProtocolHandler for the
     * queried URI does not permit proxying via HTTP.
     *
     * If a nsIProtocolHandler disallows all proxying, then filters will never
     * have a chance to intercept proxy requests for such URLs.
     *
     * @param aFilter
     *        The nsIProtocolProxyFilter instance to be registered.
     * @param aPosition
     *        The position of the filter.
     *
     * NOTE: It is possible to construct filters that compete with one another
     * in undesirable ways.  This API does not attempt to protect against such
     * problems.  It is recommended that any extensions that choose to call
     * this method make their position value configurable at runtime (perhaps
     * via the preferences service).
     */
    void registerFilter(in nsIProtocolProxyFilter aFilter,
                        in unsigned long aPosition);

    /**
     * This method may be used to unregister a proxy filter instance.  All
     * filters will be automatically unregistered at XPCOM shutdown.
     *
     * @param aFilter
     *        The nsIProtocolProxyFilter instance to be unregistered.
     */
    void unregisterFilter(in nsIProtocolProxyFilter aFilter);

     /**
      * These values correspond to the possible integer values for the
      * network.proxy.type preference.
      */ 
     const unsigned long PROXYCONFIG_DIRECT   = 0;
     const unsigned long PROXYCONFIG_MANUAL   = 1;
     const unsigned long PROXYCONFIG_PAC      = 2;
     const unsigned long PROXYCONFIG_WPAD     = 4;
     const unsigned long PROXYCONFIG_SYSTEM   = 5;

     /**
      * This attribute specifies the current type of proxy configuration.
      */
     readonly attribute unsigned long proxyConfigType;
};
