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src/core/ngx_output_chain.c  view on Meta::CPAN

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


#if 0
#define NGX_SENDFILE_LIMIT  4096
#endif

/*
 * When DIRECTIO is enabled FreeBSD, Solaris, and MacOSX read directly
 * to an application memory from a device if parameters are aligned
 * to device sector boundary (512 bytes).  They fallback to usual read
 * operation if the parameters are not aligned.
 * Linux allows DIRECTIO only if the parameters are aligned to a filesystem
 * sector boundary, otherwise it returns EINVAL.  The sector size is
 * usually 512 bytes, however, on XFS it may be 4096 bytes.
 */

#define NGX_NONE            1


static ngx_inline ngx_int_t
    ngx_output_chain_as_is(ngx_output_chain_ctx_t *ctx, ngx_buf_t *buf);
#if (NGX_HAVE_AIO_SENDFILE)
static ngx_int_t ngx_output_chain_aio_setup(ngx_output_chain_ctx_t *ctx,
    ngx_file_t *file);
#endif
static ngx_int_t ngx_output_chain_add_copy(ngx_pool_t *pool,
    ngx_chain_t **chain, ngx_chain_t *in);
static ngx_int_t ngx_output_chain_align_file_buf(ngx_output_chain_ctx_t *ctx,
    off_t bsize);
static ngx_int_t ngx_output_chain_get_buf(ngx_output_chain_ctx_t *ctx,
    off_t bsize);
static ngx_int_t ngx_output_chain_copy_buf(ngx_output_chain_ctx_t *ctx);


ngx_int_t
ngx_output_chain(ngx_output_chain_ctx_t *ctx, ngx_chain_t *in)
{
    off_t         bsize;
    ngx_int_t     rc, last;
    ngx_chain_t  *cl, *out, **last_out;

    if (ctx->in == NULL && ctx->busy == NULL
#if (NGX_HAVE_FILE_AIO || NGX_THREADS)
        && !ctx->aio
#endif
       )
    {
        /*
         * the short path for the case when the ctx->in and ctx->busy chains
         * are empty, the incoming chain is empty too or has the single buf
         * that does not require the copy
         */

        if (in == NULL) {
            return ctx->output_filter(ctx->filter_ctx, in);
        }

        if (in->next == NULL
#if (NGX_SENDFILE_LIMIT)
            && !(in->buf->in_file && in->buf->file_last > NGX_SENDFILE_LIMIT)
#endif
            && ngx_output_chain_as_is(ctx, in->buf))
        {
            return ctx->output_filter(ctx->filter_ctx, in);
        }
    }

    /* add the incoming buf to the chain ctx->in */

    if (in) {
        if (ngx_output_chain_add_copy(ctx->pool, &ctx->in, in) == NGX_ERROR) {
            return NGX_ERROR;
        }
    }

    out = NULL;
    last_out = &out;
    last = NGX_NONE;

    for ( ;; ) {

#if (NGX_HAVE_FILE_AIO || NGX_THREADS)
        if (ctx->aio) {
            return NGX_AGAIN;
        }
#endif

        while (ctx->in) {

            /*
             * cycle while there are the ctx->in bufs
             * and there are the free output bufs to copy in
             */

            bsize = ngx_buf_size(ctx->in->buf);

            if (bsize == 0 && !ngx_buf_special(ctx->in->buf)) {

                ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0,
                              "zero size buf in output "
                              "t:%d r:%d f:%d %p %p-%p %p %O-%O",
                              ctx->in->buf->temporary,
                              ctx->in->buf->recycled,
                              ctx->in->buf->in_file,
                              ctx->in->buf->start,
                              ctx->in->buf->pos,
                              ctx->in->buf->last,
                              ctx->in->buf->file,
                              ctx->in->buf->file_pos,

src/core/ngx_output_chain.c  view on Meta::CPAN

                        ngx_free_chain(ctx->pool, cl);

                    } else if (out || ctx->allocated == ctx->bufs.num) {

                        break;

                    } else if (ngx_output_chain_get_buf(ctx, bsize) != NGX_OK) {
                        return NGX_ERROR;
                    }
                }
            }

            rc = ngx_output_chain_copy_buf(ctx);

            if (rc == NGX_ERROR) {
                return rc;
            }

            if (rc == NGX_AGAIN) {
                if (out) {
                    break;
                }

                return rc;
            }

            /* delete the completed buf from the ctx->in chain */

            if (ngx_buf_size(ctx->in->buf) == 0) {
                ctx->in = ctx->in->next;
            }

            cl = ngx_alloc_chain_link(ctx->pool);
            if (cl == NULL) {
                return NGX_ERROR;
            }

            cl->buf = ctx->buf;
            cl->next = NULL;
            *last_out = cl;
            last_out = &cl->next;
            ctx->buf = NULL;
        }

        if (out == NULL && last != NGX_NONE) {

            if (ctx->in) {
                return NGX_AGAIN;
            }

            return last;
        }

        last = ctx->output_filter(ctx->filter_ctx, out);

        if (last == NGX_ERROR || last == NGX_DONE) {
            return last;
        }

        ngx_chain_update_chains(ctx->pool, &ctx->free, &ctx->busy, &out,
                                ctx->tag);
        last_out = &out;
    }
}


static ngx_inline ngx_int_t
ngx_output_chain_as_is(ngx_output_chain_ctx_t *ctx, ngx_buf_t *buf)
{
    ngx_uint_t  sendfile;

    if (ngx_buf_special(buf)) {
        return 1;
    }

#if (NGX_THREADS)
    if (buf->in_file) {
        buf->file->thread_handler = ctx->thread_handler;
        buf->file->thread_ctx = ctx->filter_ctx;
    }
#endif

    if (buf->in_file && buf->file->directio) {
        return 0;
    }

    sendfile = ctx->sendfile;

#if (NGX_SENDFILE_LIMIT)

    if (buf->in_file && buf->file_pos >= NGX_SENDFILE_LIMIT) {
        sendfile = 0;
    }

#endif

    if (!sendfile) {

        if (!ngx_buf_in_memory(buf)) {
            return 0;
        }

        buf->in_file = 0;
    }

#if (NGX_HAVE_AIO_SENDFILE)
    if (ctx->aio_preload && buf->in_file) {
        (void) ngx_output_chain_aio_setup(ctx, buf->file);
    }
#endif

    if (ctx->need_in_memory && !ngx_buf_in_memory(buf)) {
        return 0;
    }

    if (ctx->need_in_temp && (buf->memory || buf->mmap)) {
        return 0;
    }

    return 1;