| /* |
| * |
| * Copyright 2015, Google Inc. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| */ |
| |
| #include <string.h> |
| |
| #include "src/core/channel/compress_filter.h" |
| #include "src/core/channel/channel_args.h" |
| #include "src/core/compression/message_compress.h" |
| #include <grpc/compression.h> |
| #include <grpc/support/log.h> |
| #include <grpc/support/slice_buffer.h> |
| |
| typedef struct call_data { |
| gpr_slice_buffer slices; |
| int remaining_slice_bytes; |
| int no_compress; /**< whether skip compression for this specific call */ |
| |
| grpc_linked_mdelem compression_algorithm; |
| } call_data; |
| |
| typedef struct channel_data { |
| grpc_compression_algorithm compress_algorithm; |
| grpc_mdelem *compress_algorithm_md; |
| grpc_mdelem *no_compression_md; |
| } channel_data; |
| |
| /** Compress \a slices in place using \a algorithm. Returns 1 if compression did |
| * actually happen, 0 otherwise (for example if the compressed output size was |
| * larger than the raw input). |
| * |
| * Returns 1 if the data was actually compress and 0 otherwise. */ |
| static int compress_send_sb(grpc_compression_algorithm algorithm, |
| gpr_slice_buffer *slices) { |
| int did_compress; |
| gpr_slice_buffer tmp; |
| gpr_slice_buffer_init(&tmp); |
| did_compress = grpc_msg_compress(algorithm, slices, &tmp); |
| gpr_slice_buffer_swap(slices, &tmp); |
| gpr_slice_buffer_destroy(&tmp); |
| return did_compress; |
| } |
| |
| static void process_send_ops(grpc_call_element *elem, |
| grpc_stream_op_buffer *send_ops) { |
| call_data *calld = elem->call_data; |
| channel_data *channeld = elem->channel_data; |
| size_t i, j; |
| int begin_message_index = -1; |
| int metadata_op_index = -1; |
| grpc_mdelem *actual_compression_md; |
| |
| /* buffer up slices until we've processed all the expected ones (as given by |
| * GRPC_OP_BEGIN_MESSAGE) */ |
| for (i = 0; i < send_ops->nops; ++i) { |
| grpc_stream_op *sop = &send_ops->ops[i]; |
| switch (sop->type) { |
| case GRPC_OP_BEGIN_MESSAGE: |
| begin_message_index = i; |
| calld->remaining_slice_bytes = sop->data.begin_message.length; |
| calld->no_compress = |
| !!(sop->data.begin_message.flags & GRPC_WRITE_NO_COMPRESS); |
| break; |
| case GRPC_OP_SLICE: |
| if (calld->no_compress) continue; |
| GPR_ASSERT(calld->remaining_slice_bytes > 0); |
| /* add to calld->slices */ |
| gpr_slice_buffer_add(&calld->slices, sop->data.slice); |
| calld->remaining_slice_bytes -= GPR_SLICE_LENGTH(sop->data.slice); |
| if (calld->remaining_slice_bytes == 0) { |
| /* compress */ |
| if (!compress_send_sb(channeld->compress_algorithm, &calld->slices)) { |
| calld->no_compress = 1; /* GPR_TRUE */ |
| } |
| } |
| break; |
| case GRPC_OP_METADATA: |
| /* Save the index of the first metadata op, to be processed after we |
| * know whether compression actually happened */ |
| if (metadata_op_index < 0) metadata_op_index = i; |
| break; |
| case GRPC_NO_OP: |
| ; /* fallthrough, ignore */ |
| } |
| } |
| |
| GPR_ASSERT(metadata_op_index >= 0); |
| GPR_ASSERT(begin_message_index >= 0); |
| |
| /* update both the metadata and the begin_message's flags */ |
| if (calld->no_compress) { |
| /* either because the user requested the exception or because compressing |
| * would have resulted in a larger output */ |
| channeld->compress_algorithm = GRPC_COMPRESS_NONE; |
| actual_compression_md = channeld->no_compression_md; |
| /* reset the flag compression bit */ |
| send_ops->ops[begin_message_index].data.begin_message.flags &= |
| ~GRPC_WRITE_INTERNAL_COMPRESS; |
| } else { /* DID compress */ |
| actual_compression_md = channeld->compress_algorithm_md; |
| /* at this point, calld->slices contains the *compressed* slices from |
| * send_ops->ops[*]->data.slice. We now replace these input slices with the |
| * compressed ones. */ |
| for (i = 0, j = 0; i < send_ops->nops; ++i) { |
| grpc_stream_op *sop = &send_ops->ops[i]; |
| GPR_ASSERT(j < calld->slices.count); |
| switch (sop->type) { |
| case GRPC_OP_SLICE: |
| gpr_slice_unref(sop->data.slice); |
| sop->data.slice = gpr_slice_ref(calld->slices.slices[j++]); |
| break; |
| case GRPC_OP_BEGIN_MESSAGE: |
| sop->data.begin_message.length = calld->slices.length; |
| sop->data.begin_message.flags |= GRPC_WRITE_INTERNAL_COMPRESS; |
| case GRPC_NO_OP: |
| case GRPC_OP_METADATA: |
| ; /* fallthrough, ignore */ |
| } |
| } |
| } |
| |
| grpc_metadata_batch_add_head( |
| &(send_ops->ops[metadata_op_index].data.metadata), |
| &calld->compression_algorithm, grpc_mdelem_ref(actual_compression_md)); |
| } |
| |
| /* Called either: |
| - in response to an API call (or similar) from above, to send something |
| - a network event (or similar) from below, to receive something |
| op contains type and call direction information, in addition to the data |
| that is being sent or received. */ |
| static void compress_start_transport_op(grpc_call_element *elem, |
| grpc_transport_op *op) { |
| if (op->send_ops && op->send_ops->nops > 0) { |
| process_send_ops(elem, op->send_ops); |
| } |
| |
| /* pass control down the stack */ |
| grpc_call_next_op(elem, op); |
| } |
| |
| /* Called on special channel events, such as disconnection or new incoming |
| calls on the server */ |
| static void channel_op(grpc_channel_element *elem, |
| grpc_channel_element *from_elem, grpc_channel_op *op) { |
| switch (op->type) { |
| default: |
| grpc_channel_next_op(elem, op); |
| break; |
| } |
| } |
| |
| /* Constructor for call_data */ |
| static void init_call_elem(grpc_call_element *elem, |
| const void *server_transport_data, |
| grpc_transport_op *initial_op) { |
| /* grab pointers to our data from the call element */ |
| call_data *calld = elem->call_data; |
| |
| /* initialize members */ |
| gpr_slice_buffer_init(&calld->slices); |
| |
| if (initial_op) { |
| if (initial_op->send_ops && initial_op->send_ops->nops > 0) { |
| process_send_ops(elem, initial_op->send_ops); |
| } |
| } |
| } |
| |
| /* Destructor for call_data */ |
| static void destroy_call_elem(grpc_call_element *elem) { |
| /* grab pointers to our data from the call element */ |
| call_data *calld = elem->call_data; |
| gpr_slice_buffer_destroy(&calld->slices); |
| } |
| |
| /* Constructor for channel_data */ |
| static void init_channel_elem(grpc_channel_element *elem, |
| const grpc_channel_args *args, grpc_mdctx *mdctx, |
| int is_first, int is_last) { |
| channel_data *channeld = elem->channel_data; |
| const grpc_compression_level clevel = |
| grpc_channel_args_get_compression_level(args); |
| const grpc_compression_algorithm none_alg = GRPC_COMPRESS_NONE; |
| |
| /*We shouldn't be in this filter if compression is disabled. */ |
| GPR_ASSERT(clevel != GRPC_COMPRESS_LEVEL_NONE); |
| |
| channeld->compress_algorithm_md = grpc_mdelem_from_string_and_buffer( |
| mdctx, "grpc-compression-level", (gpr_uint8*)&clevel, sizeof(clevel)); |
| channeld->compress_algorithm = grpc_compression_algorithm_for_level(clevel); |
| |
| channeld->no_compression_md = grpc_mdelem_from_string_and_buffer( |
| mdctx, "grpc-compression-level", (gpr_uint8 *)&none_alg, |
| sizeof(none_alg)); |
| |
| /* The first and the last filters tend to be implemented differently to |
| handle the case that there's no 'next' filter to call on the up or down |
| path */ |
| GPR_ASSERT(!is_first); |
| GPR_ASSERT(!is_last); |
| } |
| |
| /* Destructor for channel data */ |
| static void destroy_channel_elem(grpc_channel_element *elem) { |
| channel_data *channeld = elem->channel_data; |
| grpc_mdelem_unref(channeld->compress_algorithm_md); |
| grpc_mdelem_unref(channeld->no_compression_md); |
| } |
| |
| const grpc_channel_filter grpc_compress_filter = { |
| compress_start_transport_op, channel_op, sizeof(call_data), init_call_elem, |
| destroy_call_elem, sizeof(channel_data), init_channel_elem, |
| destroy_channel_elem, "compress"}; |