mod_deflate.c

apache服务器源代码（版本号：2.2.2）

            return ap_pass_brigade(f->next, bb);
        }

        /* add immortal gzip header */
        e = apr_bucket_immortal_create(gzip_header, sizeof gzip_header,
                                       f->c->bucket_alloc);
        APR_BRIGADE_INSERT_TAIL(ctx->bb, e);

        /* If the entire Content-Encoding is "identity", we can replace it. */
        if (!encoding || !strcasecmp(encoding, "identity")) {
            apr_table_setn(r->headers_out, "Content-Encoding", "gzip");
        }
        else {
            apr_table_mergen(r->headers_out, "Content-Encoding", "gzip");
        }
        apr_table_unset(r->headers_out, "Content-Length");

        /* initialize deflate output buffer */
        ctx->stream.next_out = ctx->buffer;
        ctx->stream.avail_out = c->bufferSize;
    }

    while (!APR_BRIGADE_EMPTY(bb))
    {
        const char *data;
        apr_bucket *b;
        apr_size_t len;
        int done = 0;

        e = APR_BRIGADE_FIRST(bb);

        if (APR_BUCKET_IS_EOS(e)) {
            char *buf;
            unsigned int deflate_len;

            ctx->stream.avail_in = 0; /* should be zero already anyway */
            for (;;) {
                deflate_len = c->bufferSize - ctx->stream.avail_out;

                if (deflate_len != 0) {
                    b = apr_bucket_heap_create((char *)ctx->buffer,
                                               deflate_len, NULL,
                                               f->c->bucket_alloc);
                    APR_BRIGADE_INSERT_TAIL(ctx->bb, b);
                    ctx->stream.next_out = ctx->buffer;
                    ctx->stream.avail_out = c->bufferSize;
                }

                if (done) {
                    break;
                }

                zRC = deflate(&ctx->stream, Z_FINISH);

                if (deflate_len == 0 && zRC == Z_BUF_ERROR) {
                    zRC = Z_OK;
                }

                done = (ctx->stream.avail_out != 0 || zRC == Z_STREAM_END);

                if (zRC != Z_OK && zRC != Z_STREAM_END) {
                    break;
                }
            }

            buf = apr_palloc(r->pool, 8);
            putLong((unsigned char *)&buf[0], ctx->crc);
            putLong((unsigned char *)&buf[4], ctx->stream.total_in);

            b = apr_bucket_pool_create(buf, 8, r->pool, f->c->bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(ctx->bb, b);
            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                          "Zlib: Compressed %ld to %ld : URL %s",
                          ctx->stream.total_in, ctx->stream.total_out, r->uri);

            /* leave notes for logging */
            if (c->note_input_name) {
                apr_table_setn(r->notes, c->note_input_name,
                               (ctx->stream.total_in > 0)
                                ? apr_off_t_toa(r->pool,
                                                ctx->stream.total_in)
                                : "-");
            }

            if (c->note_output_name) {
                apr_table_setn(r->notes, c->note_output_name,
                               (ctx->stream.total_in > 0)
                                ? apr_off_t_toa(r->pool,
                                                ctx->stream.total_out)
                                : "-");
            }

            if (c->note_ratio_name) {
                apr_table_setn(r->notes, c->note_ratio_name,
                               (ctx->stream.total_in > 0)
                                ? apr_itoa(r->pool,
                                           (int)(ctx->stream.total_out
                                                 * 100
                                                 / ctx->stream.total_in))
                                : "-");
            }

            deflateEnd(&ctx->stream);

            /* Remove EOS from the old list, and insert into the new. */
            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)) {
            apr_bucket *bkt;
            apr_status_t rv;

            apr_bucket_delete(e);

            if (ctx->stream.avail_in > 0) {
                zRC = deflate(&(ctx->stream), Z_SYNC_FLUSH);
                if (zRC != Z_OK) {
                    return APR_EGENERAL;
                }
            }

            ctx->stream.next_out = ctx->buffer;
            len = c->bufferSize - ctx->stream.avail_out;

            b = apr_bucket_heap_create((char *)ctx->buffer, len,
                                       NULL, f->c->bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(ctx->bb, b);
            ctx->stream.avail_out = c->bufferSize;

            bkt = apr_bucket_flush_create(f->c->bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(ctx->bb, bkt);
            rv = ap_pass_brigade(f->next, ctx->bb);
            if (rv != APR_SUCCESS) {
                return rv;
            }
            continue;
        }

        /* read */
        apr_bucket_read(e, &data, &len, APR_BLOCK_READ);

        /* This crc32 function is from zlib. */
        ctx->crc = crc32(ctx->crc, (const Bytef *)data, len);

        /* write */
        ctx->stream.next_in = (unsigned char *)data; /* We just lost const-ness,
                                                      * but we'll just have to
                                                      * trust zlib */
        ctx->stream.avail_in = len;

        while (ctx->stream.avail_in != 0) {
            if (ctx->stream.avail_out == 0) {
                apr_status_t rv;

                ctx->stream.next_out = ctx->buffer;
                len = c->bufferSize - ctx->stream.avail_out;

                b = apr_bucket_heap_create((char *)ctx->buffer, len,
                                           NULL, f->c->bucket_alloc);
                APR_BRIGADE_INSERT_TAIL(ctx->bb, b);
                ctx->stream.avail_out = c->bufferSize;
                /* Send what we have right now to the next filter. */
                rv = ap_pass_brigade(f->next, ctx->bb);
                if (rv != APR_SUCCESS) {
                    return rv;
                }
            }

            zRC = deflate(&(ctx->stream), Z_NO_FLUSH);

            if (zRC != Z_OK)
                return APR_EGENERAL;
        }

        apr_bucket_delete(e);
    }

    apr_brigade_cleanup(bb);
    return APR_SUCCESS;
}

/* This is the deflate input filter (inflates).  */
static apr_status_t deflate_in_filter(ap_filter_t *f,
                                      apr_bucket_brigade *bb,
                                      ap_input_mode_t mode,
                                      apr_read_type_e block,
                                      apr_off_t readbytes)
{
    apr_bucket *bkt;
    request_rec *r = f->r;
    deflate_ctx *ctx = f->ctx;
    int zRC;
    apr_status_t rv;
    deflate_filter_config *c;

    /* just get out of the way of things we don't want. */
    if (mode != AP_MODE_READBYTES) {
        return ap_get_brigade(f->next, bb, mode, block, readbytes);
    }

    c = ap_get_module_config(r->server->module_config, &deflate_module);

    if (!ctx) {
        int found = 0;
        char *token, deflate_hdr[10];
        const char *encoding;
        apr_size_t len;

        /* only work on main request/no subrequests */
        if (!ap_is_initial_req(r)) {
            ap_remove_input_filter(f);
            return ap_get_brigade(f->next, bb, mode, block, readbytes);
        }

        /* Let's see what our current Content-Encoding is.
         * If gzip is present, don't gzip again.  (We could, but let's not.)
         */
        encoding = apr_table_get(r->headers_in, "Content-Encoding");
        if (encoding) {
            const char *tmp = encoding;

            token = ap_get_token(r->pool, &tmp, 0);
            while (token && token[0]) {
                if (!strcasecmp(token, "gzip")) {
                    found = 1;
                    break;
                }
                /* Otherwise, skip token */
                tmp++;
                token = ap_get_token(r->pool, &tmp, 0);
            }
        }

        if (found == 0) {
            ap_remove_input_filter(f);
            return ap_get_brigade(f->next, bb, mode, block, readbytes);
        }

        f->ctx = ctx = apr_pcalloc(f->r->pool, sizeof(*ctx));
        ctx->bb = apr_brigade_create(r->pool, f->c->bucket_alloc);
        ctx->proc_bb = apr_brigade_create(r->pool, f->c->bucket_alloc);
        ctx->buffer = apr_palloc(r->pool, c->bufferSize);

        rv = ap_get_brigade(f->next, ctx->bb, AP_MODE_READBYTES, block, 10);
        if (rv != APR_SUCCESS) {
            return rv;
        }

        len = 10;
        rv = apr_brigade_flatten(ctx->bb, deflate_hdr, &len);
        if (rv != APR_SUCCESS) {
            return rv;
        }

        /* We didn't get the magic bytes. */
        if (len != 10 ||
            deflate_hdr[0] != deflate_magic[0] ||
            deflate_hdr[1] != deflate_magic[1]) {
            return APR_EGENERAL;
        }

        /* We can't handle flags for now. */
        if (deflate_hdr[3] != 0) {
            return APR_EGENERAL;
        }

        zRC = inflateInit2(&ctx->stream, c->windowSize);

        if (zRC != Z_OK) {
            f->ctx = NULL;
            inflateEnd(&ctx->stream);
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                          "unable to init Zlib: "
                          "inflateInit2 returned %d: URL %s",
                          zRC, r->uri);
            ap_remove_input_filter(f);
            return ap_get_brigade(f->next, bb, mode, block, readbytes);
        }

        /* initialize deflate output buffer */
        ctx->stream.next_out = ctx->buffer;
        ctx->stream.avail_out = c->bufferSize;

        apr_brigade_cleanup(ctx->bb);
    }

    if (APR_BRIGADE_EMPTY(ctx->proc_bb)) {
        rv = ap_get_brigade(f->next, ctx->bb, mode, block, readbytes);

        if (rv != APR_SUCCESS) {
            /* What about APR_EAGAIN errors? */
            inflateEnd(&ctx->stream);
            return rv;
        }

        for (bkt = APR_BRIGADE_FIRST(ctx->bb);
             bkt != APR_BRIGADE_SENTINEL(ctx->bb);
             bkt = APR_BUCKET_NEXT(bkt))
        {
            const char *data;
            apr_size_t len;

            /* If we actually see the EOS, that means we screwed up! */
            if (APR_BUCKET_IS_EOS(bkt)) {
                inflateEnd(&ctx->stream);
                return APR_EGENERAL;
            }

            if (APR_BUCKET_IS_FLUSH(bkt)) {
                apr_bucket *tmp_heap;
                zRC = inflate(&(ctx->stream), Z_SYNC_FLUSH);
                if (zRC != Z_OK) {
                    inflateEnd(&ctx->stream);
                    return APR_EGENERAL;
                }

                ctx->stream.next_out = ctx->buffer;
                len = c->bufferSize - ctx->stream.avail_out;

                ctx->crc = crc32(ctx->crc, (const Bytef *)ctx->buffer, len);
                tmp_heap = apr_bucket_heap_create((char *)ctx->buffer, len,
                                                 NULL, f->c->bucket_alloc);
                APR_BRIGADE_INSERT_TAIL(ctx->proc_bb, tmp_heap);
                ctx->stream.avail_out = c->bufferSize;

                /* Move everything to the returning brigade. */
                APR_BUCKET_REMOVE(bkt);
                APR_BRIGADE_CONCAT(bb, ctx->bb);
                break;
            }

            /* read */
            apr_bucket_read(bkt, &data, &len, APR_BLOCK_READ);

            /* pass through zlib inflate. */
            ctx->stream.next_in = (unsigned char *)data;
            ctx->stream.avail_in = len;

            zRC = Z_OK;

            while (ctx->stream.avail_in != 0) {
                if (ctx->stream.avail_out == 0) {
                    apr_bucket *tmp_heap;
                    ctx->stream.next_out = ctx->buffer;
                    len = c->bufferSize - ctx->stream.avail_out;

                    ctx->crc = crc32(ctx->crc, (const Bytef *)ctx->buffer, len);
                    tmp_heap = apr_bucket_heap_create((char *)ctx->buffer, len,
                                                      NULL, f->c->bucket_alloc);
                    APR_BRIGADE_INSERT_TAIL(ctx->proc_bb, tmp_heap);
                    ctx->stream.avail_out = c->bufferSize;
                }

                zRC = inflate(&ctx->stream, Z_NO_FLUSH);

                if (zRC == Z_STREAM_END) {
                    break;
                }

                if (zRC != Z_OK) {
                    inflateEnd(&ctx->stream);
                    return APR_EGENERAL;
                }
            }
            if (zRC == Z_STREAM_END) {
                apr_bucket *tmp_heap, *eos;

                ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                              "Zlib: Inflated %ld to %ld : URL %s",