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/*
 * mod_bucketeer.c: split buckets whenever we find a control-char
 *
 * Written by Ian Holsman (IanH@apache.org)
 *
 */

#include "httpd.h"
#include "http_config.h"
#include "http_log.h"
#include "apr_strings.h"
#include "apr_general.h"
#include "util_filter.h"
#include "apr_buckets.h"
#include "http_request.h"


static const char bucketeerFilterName[] = "BUCKETEER";
module AP_MODULE_DECLARE_DATA bucketeer_module;

typedef struct bucketeer_filter_config_t
{
    char bucketdelimter;
    char passdelimiter;
    char flushdelimiter;

} bucketeer_filter_config_t;


static void *create_bucketeer_server_config(apr_pool_t *p, server_rec *s)
{
    bucketeer_filter_config_t *c = apr_pcalloc(p, sizeof *c);

    c->bucketdelimter = 0x02; /* ^B */
    c->passdelimiter = 0x10; /* ^P */
    c->flushdelimiter = 0x06; /* ^F */

    return c;
}


typedef struct bucketeer_ctx_t
{
    apr_bucket_brigade *bb;
} bucketeer_ctx_t;

static apr_status_t bucketeer_out_filter(ap_filter_t *f,
                                       apr_bucket_brigade *bb)
{
    apr_bucket *e;
    request_rec *r = f->r;
    bucketeer_ctx_t *ctx = f->ctx;
   
    bucketeer_filter_config_t *c = ap_get_module_config(r->server->module_config,
                                                    &bucketeer_module);

    /* If we don't have a context, we need to ensure that it is okay to send
     * the deflated content.  If we have a context, that means we've done
     * this before and we liked it.
     * This could be not so nice if we always fail.  But, if we succeed,
     * we're in better shape.
     */
    if (!ctx) {  
        if (!r->content_type || strncmp(r->content_type, "text/", 5)) {
            ap_remove_output_filter(f);
            return ap_pass_brigade(f->next, bb);
        }

        /* We're cool with filtering this. */
        ctx = f->ctx = apr_pcalloc(f->r->pool, sizeof(*ctx));
        ctx->bb = apr_brigade_create(f->r->pool); 
        apr_table_unset(f->r->headers_out, "Content-Length");
    }

    APR_BRIGADE_FOREACH(e, bb) {
        const char *data;
        apr_size_t len;

        apr_size_t i;
        apr_size_t lastpos;

        if (APR_BUCKET_IS_EOS(e)) {

            APR_BUCKET_REMOVE(e);
            APR_BRIGADE_INSERT_TAIL(ctx->bb, e);

            /* Okay, we've seen the EOS.
             * Time to pass it along down the chain.
             */
            return ap_pass_brigade(f->next, ctx->bb);
        }

        if (APR_BUCKET_IS_FLUSH(e)) {     
            /*
             * Ignore flush buckets for the moment.. 
             * we decide what to stream
             */
            continue;
        }

        /* read */
        apr_bucket_read(e, &data, &len, APR_BLOCK_READ);
        if (len>0) {
            lastpos=0;
            for (i=0; i<len;i++) {
                if ( data[i] == c->flushdelimiter ||data[i] == c->bucketdelimter || data[i] == c->passdelimiter) {
                    apr_bucket *p;
                    if ( i-lastpos>0) {
                        p = apr_bucket_pool_create(apr_pmemdup( f->r->pool,
                                                            &data[lastpos],
                                                            i-lastpos),
                                                    i-lastpos,
                                                    f->r->pool);
                        APR_BRIGADE_INSERT_TAIL(ctx->bb,p);
                    }
                    lastpos=i+1;
                    if ( data[i] == c->flushdelimiter) {
                        p = apr_bucket_flush_create();
                        APR_BRIGADE_INSERT_TAIL(ctx->bb,p);
                    }
                    if ( data[i] == c->flushdelimiter || data[i] == c->passdelimiter ) {
                        ap_pass_brigade(f->next, ctx->bb);
                       /* apr_brigade_cleanup(ctx->bb);*/
                    }
                }                       
            }
            /* XXX: really should append this to the next 'real' bucket */
            if ( lastpos < i ) {
                apr_bucket *p;
                p = apr_bucket_pool_create(apr_pmemdup( f->r->pool,&data[lastpos],i-lastpos),i-lastpos,f->r->pool);
                lastpos=i;
                APR_BRIGADE_INSERT_TAIL(ctx->bb,p);
            }
        }     
    }

    return APR_SUCCESS;
}

static void register_hooks(apr_pool_t * p)
{
    ap_register_output_filter(bucketeerFilterName, bucketeer_out_filter,
                              AP_FTYPE_CONTENT-1);
}

static const command_rec bucketeer_filter_cmds[] = {
    {NULL}
};

module AP_MODULE_DECLARE_DATA bucketeer_module = {
    STANDARD20_MODULE_STUFF,
    NULL,
    NULL,
    create_bucketeer_server_config,
    NULL,
    bucketeer_filter_cmds,
    register_hooks
};
