Merge pull request #2533 from dgquintas/compression-accept-encoding

Enable servers to disable compression algorithms

3 files changed, 56 insertions, 6 deletions

diff --git a/src/core/channel/compress_filter.c b/src/core/channel/compress_filter.c
index 762a4edc73..eb27252d03 100644
--- a/src/core/channel/compress_filter.c
+++ b/src/core/channel/compress_filter.c
@@ -70,6 +70,8 @@ typedef struct channel_data {
   grpc_mdelem *mdelem_accept_encoding;
   /** The default, channel-level, compression algorithm */
   grpc_compression_algorithm default_compression_algorithm;
+  /** Compression options for the channel */
+  grpc_compression_options compression_options;
 } channel_data;
 
 /** Compress \a slices in place using \a algorithm. Returns 1 if compression did
@@ -102,7 +104,17 @@ static grpc_mdelem *compression_md_filter(void *user_data, grpc_mdelem *md) {
     const char *md_c_str = grpc_mdstr_as_c_string(md->value);
     if (!grpc_compression_algorithm_parse(md_c_str, strlen(md_c_str),
                                           &calld->compression_algorithm)) {
-      gpr_log(GPR_ERROR, "Invalid compression algorithm: '%s'. Ignoring.",
+      gpr_log(GPR_ERROR,
+              "Invalid compression algorithm: '%s' (unknown). Ignoring.",
+              md_c_str);
+      calld->compression_algorithm = GRPC_COMPRESS_NONE;
+    }
+    if (grpc_compression_options_is_algorithm_enabled(
+            &channeld->compression_options, calld->compression_algorithm) == 0)
+    {
+      gpr_log(GPR_ERROR,
+              "Invalid compression algorithm: '%s' (previously disabled). "
+              "Ignoring.",
               md_c_str);
       calld->compression_algorithm = GRPC_COMPRESS_NONE;
     }
@@ -294,11 +306,21 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
   channel_data *channeld = elem->channel_data;
   grpc_compression_algorithm algo_idx;
   const char *supported_algorithms_names[GRPC_COMPRESS_ALGORITHMS_COUNT - 1];
+  size_t supported_algorithms_idx = 0;
   char *accept_encoding_str;
   size_t accept_encoding_str_len;
 
+  grpc_compression_options_init(&channeld->compression_options);
+  channeld->compression_options.enabled_algorithms_bitset =
+      grpc_channel_args_compression_algorithm_get_states(args);
+
   channeld->default_compression_algorithm =
       grpc_channel_args_get_compression_algorithm(args);
+  /* Make sure the default isn't disabled. */
+  GPR_ASSERT(grpc_compression_options_is_algorithm_enabled(
+      &channeld->compression_options, channeld->default_compression_algorithm));
+  channeld->compression_options.default_compression_algorithm =
+      channeld->default_compression_algorithm;
 
   channeld->mdstr_request_compression_algorithm_key =
       grpc_mdstr_from_string(mdctx, GRPC_COMPRESS_REQUEST_ALGORITHM_KEY, 0);
@@ -311,6 +333,11 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
 
   for (algo_idx = 0; algo_idx < GRPC_COMPRESS_ALGORITHMS_COUNT; ++algo_idx) {
     char *algorithm_name;
+    /* skip disabled algorithms */
+    if (grpc_compression_options_is_algorithm_enabled(
+            &channeld->compression_options, algo_idx) == 0) {
+      continue;
+    }
     GPR_ASSERT(grpc_compression_algorithm_name(algo_idx, &algorithm_name) != 0);
     channeld->mdelem_compression_algorithms[algo_idx] =
         grpc_mdelem_from_metadata_strings(
@@ -318,15 +345,15 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
             GRPC_MDSTR_REF(channeld->mdstr_outgoing_compression_algorithm_key),
             grpc_mdstr_from_string(mdctx, algorithm_name, 0));
     if (algo_idx > 0) {
-      supported_algorithms_names[algo_idx - 1] = algorithm_name;
+      supported_algorithms_names[supported_algorithms_idx++] = algorithm_name;
     }
   }
 
   /* TODO(dgq): gpr_strjoin_sep could be made to work with statically allocated
    * arrays, as to avoid the heap allocs */
-  accept_encoding_str = gpr_strjoin_sep(
-      supported_algorithms_names, GPR_ARRAY_SIZE(supported_algorithms_names),
-      ", ", &accept_encoding_str_len);
+  accept_encoding_str =
+      gpr_strjoin_sep(supported_algorithms_names, supported_algorithms_idx, ",",
+                      &accept_encoding_str_len);
 
   channeld->mdelem_accept_encoding = grpc_mdelem_from_metadata_strings(
       mdctx, GRPC_MDSTR_REF(channeld->mdstr_compression_capabilities_key),
diff --git a/src/core/compression/algorithm.c b/src/core/compression/algorithm.c
index 6ed6dbe93f..76d42fde0f 100644
--- a/src/core/compression/algorithm.c
+++ b/src/core/compression/algorithm.c
@@ -33,7 +33,9 @@
 
 #include <stdlib.h>
 #include <string.h>
+
 #include <grpc/compression.h>
+#include <grpc/support/useful.h>
 
 int grpc_compression_algorithm_parse(const char *name, size_t name_length,
                                      grpc_compression_algorithm *algorithm) {
@@ -102,3 +104,24 @@ grpc_compression_level grpc_compression_level_for_algorithm(
   }
   abort();
 }
+
+void grpc_compression_options_init(grpc_compression_options *opts) {
+  opts->enabled_algorithms_bitset = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT)-1;
+  opts->default_compression_algorithm = GRPC_COMPRESS_NONE;
+}
+
+void grpc_compression_options_enable_algorithm(
+    grpc_compression_options *opts, grpc_compression_algorithm algorithm) {
+  GPR_BITSET(&opts->enabled_algorithms_bitset, algorithm);
+}
+
+void grpc_compression_options_disable_algorithm(
+    grpc_compression_options *opts, grpc_compression_algorithm algorithm) {
+  GPR_BITCLEAR(&opts->enabled_algorithms_bitset, algorithm);
+}
+
+int grpc_compression_options_is_algorithm_enabled(
+    const grpc_compression_options *opts,
+    grpc_compression_algorithm algorithm) {
+  return GPR_BITGET(opts->enabled_algorithms_bitset, algorithm);
+}
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 6ece56371b..40190c2f54 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -533,7 +533,7 @@ static void set_encodings_accepted_by_peer(
   gpr_slice_buffer accept_encoding_parts;
 
   gpr_slice_buffer_init(&accept_encoding_parts);
-  gpr_slice_split(accept_encoding_slice, ", ", &accept_encoding_parts);
+  gpr_slice_split(accept_encoding_slice, ",", &accept_encoding_parts);
 
   /* No need to zero call->encodings_accepted_by_peer: grpc_call_create already
    * zeroes the whole grpc_call */