/*
 * Copyright (c) 2014-2016 DeNA Co., Ltd., Kazuho Oku, Tatsuhiro Tsujikawa
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/uio.h>
#include "h2o.h"

#ifndef IOV_MAX
#define IOV_MAX UIO_MAXIOV
#endif

#define INITIAL_INBUFSZ 8192

struct st_deferred_request_action_t {
    h2o_timeout_entry_t timeout;
    h2o_req_t *req;
};

struct st_delegate_request_deferred_t {
    struct st_deferred_request_action_t super;
    h2o_handler_t *current_handler;
};

struct st_reprocess_request_deferred_t {
    struct st_deferred_request_action_t super;
    h2o_iovec_t method;
    const h2o_url_scheme_t *scheme;
    h2o_iovec_t authority;
    h2o_iovec_t path;
    h2o_req_overrides_t *overrides;
    int is_delegated;
};

struct st_send_error_deferred_t {
    h2o_req_t *req;
    int status;
    const char *reason;
    const char *body;
    int flags;
    h2o_timeout_entry_t _timeout;
};

static void on_deferred_action_dispose(void *_action)
{
    struct st_deferred_request_action_t *action = _action;
    if (h2o_timeout_is_linked(&action->timeout))
        h2o_timeout_unlink(&action->timeout);
}

static struct st_deferred_request_action_t *create_deferred_action(h2o_req_t *req, size_t sz, h2o_timeout_cb cb)
{
    struct st_deferred_request_action_t *action = h2o_mem_alloc_shared(&req->pool, sz, on_deferred_action_dispose);
    *action = (struct st_deferred_request_action_t){{0, cb}, req};
    h2o_timeout_link(req->conn->ctx->loop, &req->conn->ctx->zero_timeout, &action->timeout);
    return action;
}

static h2o_hostconf_t *find_hostconf(h2o_hostconf_t **hostconfs, h2o_iovec_t authority, uint16_t default_port)
{
    h2o_iovec_t hostname;
    uint16_t port;
    char *hostname_lc;

    /* safe-guard for alloca */
    if (authority.len >= 65536)
        return NULL;

    /* extract the specified hostname and port */
    if (h2o_url_parse_hostport(authority.base, authority.len, &hostname, &port) == NULL)
        return NULL;
    if (port == 65535)
        port = default_port;

    /* convert supplied hostname to lower-case */
    hostname_lc = alloca(hostname.len);
    memcpy(hostname_lc, hostname.base, hostname.len);
    h2o_strtolower(hostname_lc, hostname.len);

    do {
        h2o_hostconf_t *hostconf = *hostconfs;
        if (hostconf->authority.port == port || (hostconf->authority.port == 65535 && port == default_port)) {
            if (hostconf->authority.host.base[0] == '*') {
                /* matching against "*.foo.bar" */
                size_t cmplen = hostconf->authority.host.len - 1;
                if (cmplen < hostname.len &&
                    memcmp(hostconf->authority.host.base + 1, hostname_lc + hostname.len - cmplen, cmplen) == 0)
                    return hostconf;
            } else {
                /* exact match */
                if (h2o_memis(hostconf->authority.host.base, hostconf->authority.host.len, hostname_lc, hostname.len))
                    return hostconf;
            }
        }
    } while (*++hostconfs != NULL);

    return NULL;
}

static h2o_hostconf_t *setup_before_processing(h2o_req_t *req)
{
    h2o_context_t *ctx = req->conn->ctx;
    h2o_hostconf_t *hostconf;

    h2o_get_timestamp(ctx, &req->pool, &req->processed_at);

    /* find the host context */
    if (req->input.authority.base != NULL) {
        if (req->conn->hosts[1] == NULL ||
            (hostconf = find_hostconf(req->conn->hosts, req->input.authority, req->input.scheme->default_port)) == NULL)
            hostconf = *req->conn->hosts;
    } else {
        /* set the authority name to the default one */
        hostconf = *req->conn->hosts;
        req->input.authority = hostconf->authority.hostport;
    }

    req->scheme = req->input.scheme;
    req->method = req->input.method;
    req->authority = req->input.authority;
    req->path = req->input.path;
    req->path_normalized =
        h2o_url_normalize_path(&req->pool, req->input.path.base, req->input.path.len, &req->query_at, &req->norm_indexes);
    req->input.query_at = req->query_at; /* we can do this since input.path == path */

    return hostconf;
}

static void call_handlers(h2o_req_t *req, h2o_handler_t **handler)
{
    h2o_handler_t **end = req->pathconf->handlers.entries + req->pathconf->handlers.size;

    for (; handler != end; ++handler)
        if ((*handler)->on_req(*handler, req) == 0)
            return;

    h2o_send_error_404(req, "File Not Found", "not found", 0);
}

static void process_hosted_request(h2o_req_t *req, h2o_hostconf_t *hostconf)
{
    h2o_pathconf_t *selected_pathconf = &hostconf->fallback_path;
    size_t i;

    /* setup pathconf, or redirect to "path/" */
    for (i = 0; i != hostconf->paths.size; ++i) {
        h2o_pathconf_t *candidate = hostconf->paths.entries + i;
        if (req->path_normalized.len >= candidate->path.len &&
            memcmp(req->path_normalized.base, candidate->path.base, candidate->path.len) == 0 &&
            (candidate->path.base[candidate->path.len - 1] == '/' || req->path_normalized.len == candidate->path.len ||
             req->path_normalized.base[candidate->path.len] == '/')) {
            selected_pathconf = candidate;
            break;
        }
    }
    h2o_req_bind_conf(req, hostconf, selected_pathconf);

    call_handlers(req, req->pathconf->handlers.entries);
}

static void deferred_proceed_cb(h2o_timeout_entry_t *entry)
{
    h2o_req_t *req = H2O_STRUCT_FROM_MEMBER(h2o_req_t, _timeout_entry, entry);
    h2o_proceed_response(req);
}

static void close_generator_and_filters(h2o_req_t *req)
{
    /* close the generator if it is still open */
    if (req->_generator != NULL) {
        /* close generator */
        if (req->_generator->stop != NULL)
            req->_generator->stop(req->_generator, req);
        req->_generator = NULL;
    }
    /* close the ostreams still open */
    while (req->_ostr_top->next != NULL) {
        if (req->_ostr_top->stop != NULL)
            req->_ostr_top->stop(req->_ostr_top, req);
        req->_ostr_top = req->_ostr_top->next;
    }
}

static void reset_response(h2o_req_t *req)
{
    req->res = (h2o_res_t){0, NULL, SIZE_MAX};
    req->res.reason = "OK";
    req->_next_filter_index = 0;
    req->bytes_sent = 0;
}

static void retain_original_response(h2o_req_t *req)
{
    if (req->res.original.status != 0)
        return;

    req->res.original.status = req->res.status;
    h2o_vector_reserve(&req->pool, &req->res.original.headers, req->res.headers.size);
    h2o_memcpy(req->res.original.headers.entries, req->res.headers.entries,
               sizeof(req->res.headers.entries[0]) * req->res.headers.size);
    req->res.original.headers.size = req->res.headers.size;
}

void h2o_init_request(h2o_req_t *req, h2o_conn_t *conn, h2o_req_t *src)
{
    /* clear all memory (expect memory pool, since it is large) */
    memset(req, 0, offsetof(h2o_req_t, pool));

    /* init memory pool (before others, since it may be used) */
    h2o_mem_init_pool(&req->pool);

    /* init properties that should be initialized to non-zero */
    req->conn = conn;
    req->_timeout_entry.cb = deferred_proceed_cb;
    req->res.reason = "OK"; /* default to "OK" regardless of the status value, it's not important after all (never sent in HTTP2) */
    req->res.content_length = SIZE_MAX;
    req->preferred_chunk_size = SIZE_MAX;

    if (src != NULL) {
        size_t i;
#define COPY(buf)                                                                                                                  \
    do {                                                                                                                           \
        req->buf.base = h2o_mem_alloc_pool(&req->pool, src->buf.len);                                                              \
        memcpy(req->buf.base, src->buf.base, src->buf.len);                                                                        \
        req->buf.len = src->buf.len;                                                                                               \
    } while (0)
        COPY(input.authority);
        COPY(input.method);
        COPY(input.path);
        req->input.scheme = src->input.scheme;
        req->version = src->version;
        req->entity = src->entity;
        req->http1_is_persistent = src->http1_is_persistent;
        req->timestamps = src->timestamps;
        if (src->upgrade.base != NULL) {
            COPY(upgrade);
        } else {
            req->upgrade.base = NULL;
            req->upgrade.len = 0;
        }
#undef COPY
        h2o_vector_reserve(&req->pool, &req->headers, src->headers.size);
        req->headers.size = src->headers.size;
        for (i = 0; i != src->headers.size; ++i) {
            h2o_header_t *dst_header = req->headers.entries + i, *src_header = src->headers.entries + i;
            if (h2o_iovec_is_token(src_header->name)) {
                dst_header->name = src_header->name;
            } else {
                dst_header->name = h2o_mem_alloc_pool(&req->pool, sizeof(*dst_header->name));
                *dst_header->name = h2o_strdup(&req->pool, src_header->name->base, src_header->name->len);
            }
            dst_header->value = h2o_strdup(&req->pool, src_header->value.base, src_header->value.len);
            if (!src_header->orig_name)
                dst_header->orig_name = NULL;
            else
                dst_header->orig_name = h2o_strdup(&req->pool, src_header->orig_name, src_header->name->len).base;
        }
        if (src->env.size != 0) {
            h2o_vector_reserve(&req->pool, &req->env, src->env.size);
            req->env.size = src->env.size;
            for (i = 0; i != req->env.size; ++i)
                req->env.entries[i] = h2o_strdup(&req->pool, src->env.entries[i].base, src->env.entries[i].len);
        }
    }
}

void h2o_dispose_request(h2o_req_t *req)
{
    close_generator_and_filters(req);

    h2o_timeout_unlink(&req->_timeout_entry);

    if (req->version != 0 && req->pathconf != NULL) {
        h2o_logger_t **logger = req->pathconf->loggers.entries, **end = logger + req->pathconf->loggers.size;
        for (; logger != end; ++logger) {
            (*logger)->log_access((*logger), req);
        }
    }

    h2o_mem_clear_pool(&req->pool);
}

void h2o_process_request(h2o_req_t *req)
{
    h2o_hostconf_t *hostconf = setup_before_processing(req);
    process_hosted_request(req, hostconf);
}

void h2o_delegate_request(h2o_req_t *req, h2o_handler_t *current_handler)
{
    h2o_handler_t **handler = req->pathconf->handlers.entries, **end = handler + req->pathconf->handlers.size;

    for (; handler != end; ++handler) {
        if (*handler == current_handler) {
            ++handler;
            break;
        }
    }
    call_handlers(req, handler);
}

static void on_delegate_request_cb(h2o_timeout_entry_t *entry)
{
    struct st_delegate_request_deferred_t *args =
        H2O_STRUCT_FROM_MEMBER(struct st_delegate_request_deferred_t, super.timeout, entry);
    h2o_delegate_request(args->super.req, args->current_handler);
}

void h2o_delegate_request_deferred(h2o_req_t *req, h2o_handler_t *current_handler)
{
    struct st_delegate_request_deferred_t *args =
        (struct st_delegate_request_deferred_t *)create_deferred_action(req, sizeof(*args), on_delegate_request_cb);
    args->current_handler = current_handler;
}

void h2o_reprocess_request(h2o_req_t *req, h2o_iovec_t method, const h2o_url_scheme_t *scheme, h2o_iovec_t authority,
                           h2o_iovec_t path, h2o_req_overrides_t *overrides, int is_delegated)
{
    h2o_hostconf_t *hostconf;

    retain_original_response(req);

    /* close generators and filters that are already running */
    close_generator_and_filters(req);

    /* setup the request/response parameters */
    req->method = method;
    req->scheme = scheme;
    req->authority = authority;
    req->path = path;
    req->path_normalized = h2o_url_normalize_path(&req->pool, req->path.base, req->path.len, &req->query_at, &req->norm_indexes);
    req->overrides = overrides;
    req->res_is_delegated |= is_delegated;
    reset_response(req);

    /* check the delegation (or reprocess) counter */
    if (req->res_is_delegated) {
        if (req->num_delegated == req->conn->ctx->globalconf->max_delegations) {
            /* TODO log */
            h2o_send_error_502(req, "Gateway Error", "too many internal delegations", 0);
            return;
        }
        ++req->num_delegated;
    } else {
        if (req->num_reprocessed >= 5) {
            /* TODO log */
            h2o_send_error_502(req, "Gateway Error", "too many internal reprocesses", 0);
            return;
        }
        ++req->num_reprocessed;
    }

    /* handle the response using the handlers, if hostconf exists */
    h2o_hostconf_t **hosts = is_delegated ? req->conn->ctx->globalconf->hosts : req->conn->hosts;
    if (req->overrides == NULL && (hostconf = find_hostconf(hosts, req->authority, req->scheme->default_port)) != NULL) {
        req->pathconf = NULL;
        process_hosted_request(req, hostconf);
        return;
    }

    /* uses the current pathconf, in other words, proxy uses the previous pathconf for building filters */
    h2o__proxy_process_request(req);
}

static void on_reprocess_request_cb(h2o_timeout_entry_t *entry)
{
    struct st_reprocess_request_deferred_t *args =
        H2O_STRUCT_FROM_MEMBER(struct st_reprocess_request_deferred_t, super.timeout, entry);
    h2o_reprocess_request(args->super.req, args->method, args->scheme, args->authority, args->path, args->overrides,
                          args->is_delegated);
}

void h2o_reprocess_request_deferred(h2o_req_t *req, h2o_iovec_t method, const h2o_url_scheme_t *scheme, h2o_iovec_t authority,
                                    h2o_iovec_t path, h2o_req_overrides_t *overrides, int is_delegated)
{
    struct st_reprocess_request_deferred_t *args =
        (struct st_reprocess_request_deferred_t *)create_deferred_action(req, sizeof(*args), on_reprocess_request_cb);
    args->method = method;
    args->scheme = scheme;
    args->authority = authority;
    args->path = path;
    args->overrides = overrides;
    args->is_delegated = is_delegated;
}

void h2o_start_response(h2o_req_t *req, h2o_generator_t *generator)
{
    retain_original_response(req);

    /* set generator */
    assert(req->_generator == NULL);
    req->_generator = generator;

    /* setup response filters */
    if (req->prefilters != NULL) {
        req->prefilters->on_setup_ostream(req->prefilters, req, &req->_ostr_top);
    } else {
        h2o_setup_next_ostream(req, &req->_ostr_top);
    }
}

void h2o_send(h2o_req_t *req, h2o_iovec_t *bufs, size_t bufcnt, h2o_send_state_t state)
{
    assert(req->_generator != NULL);

    if (!h2o_send_state_is_in_progress(state))
        req->_generator = NULL;

    req->_ostr_top->do_send(req->_ostr_top, req, bufs, bufcnt, state);
}

h2o_req_prefilter_t *h2o_add_prefilter(h2o_req_t *req, size_t sz)
{
    h2o_req_prefilter_t *prefilter = h2o_mem_alloc_pool(&req->pool, sz);
    prefilter->next = req->prefilters;
    req->prefilters = prefilter;
    return prefilter;
}

h2o_ostream_t *h2o_add_ostream(h2o_req_t *req, size_t sz, h2o_ostream_t **slot)
{
    h2o_ostream_t *ostr = h2o_mem_alloc_pool(&req->pool, sz);
    ostr->next = *slot;
    ostr->do_send = NULL;
    ostr->stop = NULL;
    ostr->start_pull = NULL;

    *slot = ostr;

    return ostr;
}

static void apply_env(h2o_req_t *req, h2o_envconf_t *env)
{
    size_t i;

    if (env->parent != NULL)
        apply_env(req, env->parent);
    for (i = 0; i != env->unsets.size; ++i)
        h2o_req_unsetenv(req, env->unsets.entries[i].base, env->unsets.entries[i].len);
    for (i = 0; i != env->sets.size; i += 2)
        *h2o_req_getenv(req, env->sets.entries[i].base, env->sets.entries[i].len, 1) = env->sets.entries[i + 1];
}

void h2o_req_bind_conf(h2o_req_t *req, h2o_hostconf_t *hostconf, h2o_pathconf_t *pathconf)
{
    req->hostconf = hostconf;
    req->pathconf = pathconf;
    if (pathconf->env != NULL)
        apply_env(req, pathconf->env);
}

void h2o_ostream_send_next(h2o_ostream_t *ostream, h2o_req_t *req, h2o_iovec_t *bufs, size_t bufcnt, h2o_send_state_t state)
{
    if (!h2o_send_state_is_in_progress(state)) {
        assert(req->_ostr_top == ostream);
        req->_ostr_top = ostream->next;
    } else if (bufcnt == 0) {
        h2o_timeout_link(req->conn->ctx->loop, &req->conn->ctx->zero_timeout, &req->_timeout_entry);
        return;
    }
    ostream->next->do_send(ostream->next, req, bufs, bufcnt, state);
}

void h2o_req_fill_mime_attributes(h2o_req_t *req)
{
    ssize_t content_type_index;
    h2o_mimemap_type_t *mime;

    if (req->res.mime_attr != NULL)
        return;

    if ((content_type_index = h2o_find_header(&req->res.headers, H2O_TOKEN_CONTENT_TYPE, -1)) != -1 &&
        (mime = h2o_mimemap_get_type_by_mimetype(req->pathconf->mimemap, req->res.headers.entries[content_type_index].value, 0)) !=
            NULL)
        req->res.mime_attr = &mime->data.attr;
    else
        req->res.mime_attr = &h2o_mime_attributes_as_is;
}

void h2o_send_inline(h2o_req_t *req, const char *body, size_t len)
{
    static h2o_generator_t generator = {NULL, NULL};

    h2o_iovec_t buf = h2o_strdup(&req->pool, body, len);
    /* the function intentionally does not set the content length, since it may be used for generating 304 response, etc. */
    /* req->res.content_length = buf.len; */

    h2o_start_response(req, &generator);

    if (h2o_memis(req->input.method.base, req->input.method.len, H2O_STRLIT("HEAD")))
        h2o_send(req, NULL, 0, H2O_SEND_STATE_FINAL);
    else
        h2o_send(req, &buf, 1, H2O_SEND_STATE_FINAL);
}

void h2o_send_error_generic(h2o_req_t *req, int status, const char *reason, const char *body, int flags)
{
    if (req->pathconf == NULL) {
        h2o_hostconf_t *hostconf = setup_before_processing(req);
        h2o_req_bind_conf(req, hostconf, &hostconf->fallback_path);
    }

    if ((flags & H2O_SEND_ERROR_HTTP1_CLOSE_CONNECTION) != 0)
        req->http1_is_persistent = 0;

    req->res.status = status;
    req->res.reason = reason;
    req->res.content_length = strlen(body);

    if ((flags & H2O_SEND_ERROR_KEEP_HEADERS) == 0)
        memset(&req->res.headers, 0, sizeof(req->res.headers));

    h2o_add_header(&req->pool, &req->res.headers, H2O_TOKEN_CONTENT_TYPE, NULL, H2O_STRLIT("text/plain; charset=utf-8"));

    h2o_send_inline(req, body, SIZE_MAX);
}

#define DECL_SEND_ERROR_DEFERRED(status_)                                                                                          \
    static void send_error_deferred_cb_##status_(h2o_timeout_entry_t *entry)                                                       \
    {                                                                                                                              \
        struct st_send_error_deferred_t *args = H2O_STRUCT_FROM_MEMBER(struct st_send_error_deferred_t, _timeout, entry);          \
        reset_response(args->req);                                                                                                 \
        args->req->conn->ctx->emitted_error_status[H2O_STATUS_ERROR_##status_]++;                                                  \
        h2o_send_error_generic(args->req, args->status, args->reason, args->body, args->flags);                                    \
    }                                                                                                                              \
                                                                                                                                   \
    static void h2o_send_error_deferred_##status_(h2o_req_t *req, const char *reason, const char *body, int flags)                 \
    {                                                                                                                              \
        struct st_send_error_deferred_t *args = h2o_mem_alloc_pool(&req->pool, sizeof(*args));                                     \
        *args = (struct st_send_error_deferred_t){req, status_, reason, body, flags};                                              \
        args->_timeout.cb = send_error_deferred_cb_##status_;                                                                      \
        h2o_timeout_link(req->conn->ctx->loop, &req->conn->ctx->zero_timeout, &args->_timeout);                                    \
    }

DECL_SEND_ERROR_DEFERRED(502)

#undef DECL_SEND_ERROR_DEFERRED

void h2o_req_log_error(h2o_req_t *req, const char *module, const char *fmt, ...)
{
#define INITIAL_BUF_SIZE 256

    char *errbuf = h2o_mem_alloc_pool(&req->pool, INITIAL_BUF_SIZE);
    int errlen;
    va_list args;

    va_start(args, fmt);
    errlen = vsnprintf(errbuf, INITIAL_BUF_SIZE, fmt, args);
    va_end(args);

    if (errlen >= INITIAL_BUF_SIZE) {
        errbuf = h2o_mem_alloc_pool(&req->pool, errlen + 1);
        va_start(args, fmt);
        errlen = vsnprintf(errbuf, errlen + 1, fmt, args);
        va_end(args);
    }

#undef INITIAL_BUF_SIZE

    /* save the log */
    h2o_vector_reserve(&req->pool, &req->error_logs, req->error_logs.size + 1);
    req->error_logs.entries[req->error_logs.size++] = (h2o_req_error_log_t){module, h2o_iovec_init(errbuf, errlen)};

    if (req->pathconf->error_log.emit_request_errors) {
        /* build prefix */
        char *prefix = alloca(sizeof("[] in request::") + 32 + strlen(module)), *p = prefix;
        p += sprintf(p, "[%s] in request:", module);
        if (req->path.len < 32) {
            memcpy(p, req->path.base, req->path.len);
            p += req->path.len;
        } else {
            memcpy(p, req->path.base, 29);
            p += 29;
            memcpy(p, "...", 3);
            p += 3;
        }
        *p++ = ':';
        /* use writev(2) to emit error atomically */
        struct iovec vecs[] = {{prefix, p - prefix}, {errbuf, errlen}, {"\n", 1}};
        H2O_BUILD_ASSERT(sizeof(vecs) / sizeof(vecs[0]) < IOV_MAX);
        writev(2, vecs, sizeof(vecs) / sizeof(vecs[0]));
    }
}

void h2o_send_redirect(h2o_req_t *req, int status, const char *reason, const char *url, size_t url_len)
{
    if (req->res_is_delegated) {
        h2o_iovec_t method = h2o_get_redirect_method(req->method, status);
        h2o_send_redirect_internal(req, method, url, url_len, 0);
        return;
    }

    static h2o_generator_t generator = {NULL, NULL};
    static const h2o_iovec_t body_prefix = {H2O_STRLIT("<!DOCTYPE html><TITLE>Moved</TITLE><P>The document has moved <A HREF=\"")};
    static const h2o_iovec_t body_suffix = {H2O_STRLIT("\">here</A>")};

    /* build and send response */
    h2o_iovec_t bufs[3];
    size_t bufcnt;
    if (h2o_memis(req->input.method.base, req->input.method.len, H2O_STRLIT("HEAD"))) {
        req->res.content_length = SIZE_MAX;
        bufcnt = 0;
    } else {
        bufs[0] = body_prefix;
        bufs[1] = h2o_htmlescape(&req->pool, url, url_len);
        bufs[2] = body_suffix;
        bufcnt = 3;
        req->res.content_length = body_prefix.len + bufs[1].len + body_suffix.len;
    }
    req->res.status = status;
    req->res.reason = reason;
    req->res.headers = (h2o_headers_t){NULL};
    h2o_add_header(&req->pool, &req->res.headers, H2O_TOKEN_LOCATION, NULL, url, url_len);
    h2o_add_header(&req->pool, &req->res.headers, H2O_TOKEN_CONTENT_TYPE, NULL, H2O_STRLIT("text/html; charset=utf-8"));
    h2o_start_response(req, &generator);
    h2o_send(req, bufs, bufcnt, H2O_SEND_STATE_FINAL);
}

void h2o_send_redirect_internal(h2o_req_t *req, h2o_iovec_t method, const char *url_str, size_t url_len, int preserve_overrides)
{
    h2o_url_t url;

    /* parse the location URL */
    if (h2o_url_parse_relative(url_str, url_len, &url) != 0) {
        /* TODO log fprintf(stderr, "[proxy] cannot handle location header: %.*s\n", (int)url_len, url); */
        h2o_send_error_deferred_502(req, "Gateway Error", "internal error", 0);
        return;
    }
    /* convert the location to absolute (while creating copies of the values passed to the deferred call) */
    if (url.scheme == NULL)
        url.scheme = req->scheme;
    if (url.authority.base == NULL) {
        if (req->hostconf != NULL)
            url.authority = req->hostconf->authority.hostport;
        else
            url.authority = req->authority;
    } else {
        if (h2o_lcstris(url.authority.base, url.authority.len, req->authority.base, req->authority.len)) {
            url.authority = req->authority;
        } else {
            url.authority = h2o_strdup(&req->pool, url.authority.base, url.authority.len);
            preserve_overrides = 0;
        }
    }
    h2o_iovec_t base_path = req->path;
    h2o_url_resolve_path(&base_path, &url.path);
    url.path = h2o_concat(&req->pool, base_path, url.path);

    h2o_reprocess_request_deferred(req, method, url.scheme, url.authority, url.path, preserve_overrides ? req->overrides : NULL, 1);
}

h2o_iovec_t h2o_get_redirect_method(h2o_iovec_t method, int status)
{
    if (h2o_memis(method.base, method.len, H2O_STRLIT("POST")) && !(status == 307 || status == 308))
        method = h2o_iovec_init(H2O_STRLIT("GET"));
    return method;
}

h2o_iovec_t h2o_push_path_in_link_header(h2o_req_t *req, const char *value, size_t value_len)
{
    int i;
    h2o_iovec_t ret = h2o_iovec_init(value, value_len);
    if (req->conn->callbacks->push_path == NULL)
        return ret;

    h2o_iovec_vector_t paths = h2o_extract_push_path_from_link_header(
        &req->pool, value, value_len, req->path_normalized, req->input.scheme, req->input.authority,
        req->res_is_delegated ? req->scheme : NULL, req->res_is_delegated ? &req->authority : NULL, &ret);
    if (paths.size == 0)
        return ret;

    for (i = 0; i < paths.size; i++) {
        req->conn->callbacks->push_path(req, paths.entries[i].base, paths.entries[i].len);
    }
    return ret;
}