Add grpc_channel_arg_get_integer() utility function.

src/core/ext/client_config/subchannel.c

@@ -33,6 +33,7 @@
 
 #include "src/core/ext/client_config/subchannel.h"
 
+#include <limits.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
@@ -347,21 +348,16 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
       }
       if (0 ==
           strcmp(c->args->args[i].key, GRPC_ARG_MAX_RECONNECT_BACKOFF_MS)) {
-        if (c->args->args[i].type == GRPC_ARG_INTEGER) {
+        const grpc_integer_options options = {-1, 0, INT_MAX};
-          if (c->args->args[i].value.integer >= 0) {
+        const int value = grpc_channel_arg_get_integer(&c->args->args[i],
+                                                       options);
+        if (value >= 0) {
           gpr_backoff_init(
               &c->backoff_state, GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER,
               GRPC_SUBCHANNEL_RECONNECT_JITTER,
-                GPR_MIN(c->args->args[i].value.integer,
+              GPR_MIN(value,
                       GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS * 1000),
-                c->args->args[i].value.integer);
+              value);
-          } else {
-            gpr_log(GPR_ERROR, GRPC_ARG_MAX_RECONNECT_BACKOFF_MS
-                    " : must be non-negative");
-          }
-        } else {
-          gpr_log(GPR_ERROR,
-                  GRPC_ARG_MAX_RECONNECT_BACKOFF_MS " : must be an integer");
         }
       }
     }

src/core/ext/transport/chttp2/transport/chttp2_transport.c

@@ -33,6 +33,7 @@
 
 #include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
 
+#include <limits.h>
 #include <math.h>
 #include <stdio.h>
 #include <string.h>
@@ -46,6 +47,7 @@
 #include "src/core/ext/transport/chttp2/transport/http2_errors.h"
 #include "src/core/ext/transport/chttp2/transport/internal.h"
 #include "src/core/ext/transport/chttp2/transport/status_conversion.h"
+#include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/http/parser.h"
 #include "src/core/lib/iomgr/workqueue.h"
 #include "src/core/lib/profiling/timers.h"
@@ -337,76 +339,66 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
         if (is_client) {
           gpr_log(GPR_ERROR, "%s: is ignored on the client",
                   GRPC_ARG_MAX_CONCURRENT_STREAMS);
-        } else if (channel_args->args[i].type != GRPC_ARG_INTEGER) {
-          gpr_log(GPR_ERROR, "%s: must be an integer",
-                  GRPC_ARG_MAX_CONCURRENT_STREAMS);
         } else {
-          push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
+          const grpc_integer_options options = {-1, 0, INT_MAX};
-                       (uint32_t)channel_args->args[i].value.integer);
+          const int value = grpc_channel_arg_get_integer(&channel_args->args[i],
+                                                         options);
+          if (value >= 0) {
+            push_setting(exec_ctx, t,
+                         GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
+                         (uint32_t)value);
+          }
         }
       } else if (0 == strcmp(channel_args->args[i].key,
                              GRPC_ARG_HTTP2_INITIAL_SEQUENCE_NUMBER)) {
-        if (channel_args->args[i].type != GRPC_ARG_INTEGER) {
+        const grpc_integer_options options = {-1, 0, INT_MAX};
-          gpr_log(GPR_ERROR, "%s: must be an integer",
+        const int value = grpc_channel_arg_get_integer(&channel_args->args[i],
-                  GRPC_ARG_HTTP2_INITIAL_SEQUENCE_NUMBER);
+                                                       options);
-        } else if ((t->global.next_stream_id & 1) !=
+        if (value >= 0) {
-                   (channel_args->args[i].value.integer & 1)) {
+          if ((t->global.next_stream_id & 1) != (value & 1)) {
             gpr_log(GPR_ERROR, "%s: low bit must be %d on %s",
                     GRPC_ARG_HTTP2_INITIAL_SEQUENCE_NUMBER,
                     t->global.next_stream_id & 1,
                     is_client ? "client" : "server");
           } else {
-          t->global.next_stream_id =
+            t->global.next_stream_id = (uint32_t)value;
-              (uint32_t)channel_args->args[i].value.integer;
+          }
         }
       } else if (0 == strcmp(channel_args->args[i].key,
                              GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES)) {
-        if (channel_args->args[i].type != GRPC_ARG_INTEGER) {
+        const grpc_integer_options options = {-1, 5, INT_MAX};
-          gpr_log(GPR_ERROR, "%s: must be an integer",
+        const int value = grpc_channel_arg_get_integer(&channel_args->args[i],
-                  GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES);
+                                                       options);
-        } else if (channel_args->args[i].value.integer <= 5) {
+        if (value >= 0) {
-          gpr_log(GPR_ERROR, "%s: must be at least 5",
+          t->global.stream_lookahead = (uint32_t)value;
-                  GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES);
-        } else {
-          t->global.stream_lookahead =
-              (uint32_t)channel_args->args[i].value.integer;
         }
       } else if (0 == strcmp(channel_args->args[i].key,
                              GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER)) {
-        if (channel_args->args[i].type != GRPC_ARG_INTEGER) {
+        const grpc_integer_options options = {-1, 0, INT_MAX};
-          gpr_log(GPR_ERROR, "%s: must be an integer",
+        const int value = grpc_channel_arg_get_integer(&channel_args->args[i],
-                  GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER);
+                                                       options);
-        } else if (channel_args->args[i].value.integer < 0) {
+        if (value >= 0) {
-          gpr_log(GPR_ERROR, "%s: must be non-negative",
-                  GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER);
-        } else {
           push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE,
-                       (uint32_t)channel_args->args[i].value.integer);
+                       (uint32_t)value);
         }
       } else if (0 == strcmp(channel_args->args[i].key,
                              GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_ENCODER)) {
-        if (channel_args->args[i].type != GRPC_ARG_INTEGER) {
+        const grpc_integer_options options = {-1, 0, INT_MAX};
-          gpr_log(GPR_ERROR, "%s: must be an integer",
+        const int value = grpc_channel_arg_get_integer(&channel_args->args[i],
-                  GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_ENCODER);
+                                                       options);
-        } else if (channel_args->args[i].value.integer < 0) {
+        if (value >= 0) {
-          gpr_log(GPR_ERROR, "%s: must be non-negative",
-                  GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_ENCODER);
-        } else {
           grpc_chttp2_hpack_compressor_set_max_usable_size(
               &t->writing.hpack_compressor,
-              (uint32_t)channel_args->args[i].value.integer);
+              (uint32_t)value);
         }
       } else if (0 == strcmp(channel_args->args[i].key,
                              GRPC_ARG_MAX_METADATA_SIZE)) {
-        if (channel_args->args[i].type != GRPC_ARG_INTEGER) {
+        const grpc_integer_options options = {-1, 0, INT_MAX};
-          gpr_log(GPR_ERROR, "%s: must be an integer",
+        const int value = grpc_channel_arg_get_integer(&channel_args->args[i],
-                  GRPC_ARG_MAX_METADATA_SIZE);
+                                                       options);
-        } else if (channel_args->args[i].value.integer < 0) {
+        if (value >= 0) {
-          gpr_log(GPR_ERROR, "%s: must be non-negative",
-                  GRPC_ARG_MAX_METADATA_SIZE);
-        } else {
           push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
-                       (uint32_t)channel_args->args[i].value.integer);
+                       (uint32_t)value);
         }
       }
     }

src/core/lib/channel/channel_args.c

@@ -271,3 +271,21 @@ int grpc_channel_args_compare(const grpc_channel_args *a,
   }
   return 0;
 }
+
+int grpc_channel_arg_get_integer(grpc_arg *arg, grpc_integer_options options) {
+  if (arg->type != GRPC_ARG_INTEGER) {
+    gpr_log(GPR_ERROR, "%s ignored: it must be an integer", arg->key);
+    return options.default_value;
+  }
+  if (arg->value.integer < options.min_value) {
+    gpr_log(GPR_ERROR, "%s ignored: it must be >= %d", arg->key,
+            options.min_value);
+    return options.default_value;
+  }
+  if (arg->value.integer > options.max_value) {
+    gpr_log(GPR_ERROR, "%s ignored: it must be <= %d", arg->key,
+            options.max_value);
+    return options.default_value;
+  }
+  return arg->value.integer;
+}

src/core/lib/channel/channel_args.h

@@ -89,4 +89,12 @@ uint32_t grpc_channel_args_compression_algorithm_get_states(
 int grpc_channel_args_compare(const grpc_channel_args *a,
                               const grpc_channel_args *b);
 
+/** Returns the value of \a arg, subject to the contraints in \a options. */
+typedef struct grpc_integer_options {
+  int default_value;  // Return this if value is outside of expected bounds.
+  int min_value;
+  int max_value;
+} grpc_integer_options;
+int grpc_channel_arg_get_integer(grpc_arg *arg, grpc_integer_options options);
+
 #endif /* GRPC_CORE_LIB_CHANNEL_CHANNEL_ARGS_H */

src/core/lib/channel/message_size_filter.c

@@ -31,12 +31,15 @@
 
 #include "src/core/lib/channel/message_size_filter.h"
 
+#include <limits.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include "src/core/lib/channel/channel_args.h"
+
 // The protobuf library will (by default) start warning at 100 megs.
 #define DEFAULT_MAX_MESSAGE_LENGTH (4 * 1024 * 1024)
 
@@ -129,32 +132,17 @@ static void init_channel_elem(grpc_exec_ctx* exec_ctx,
   memset(chand, 0, sizeof(*chand));
   chand->max_send_size = DEFAULT_MAX_MESSAGE_LENGTH;
   chand->max_recv_size = DEFAULT_MAX_MESSAGE_LENGTH;
+  const grpc_integer_options options = {DEFAULT_MAX_MESSAGE_LENGTH, 0, INT_MAX};
   for (size_t i = 0; i < args->channel_args->num_args; ++i) {
     if (strcmp(args->channel_args->args[i].key,
                GRPC_ARG_MAX_SEND_MESSAGE_LENGTH) == 0) {
-      if (args->channel_args->args[i].type != GRPC_ARG_INTEGER) {
+      chand->max_send_size = (size_t)grpc_channel_arg_get_integer(
-        gpr_log(GPR_ERROR, "%s ignored: it must be an integer",
+          &args->channel_args->args[i], options);
-                GRPC_ARG_MAX_SEND_MESSAGE_LENGTH);
-      } else if (args->channel_args->args[i].value.integer < 0) {
-        gpr_log(GPR_ERROR, "%s ignored: it must be >= 0",
-                GRPC_ARG_MAX_SEND_MESSAGE_LENGTH);
-      } else {
-        chand->max_send_size =
-            (size_t)args->channel_args->args[i].value.integer;
-      }
     }
     if (strcmp(args->channel_args->args[i].key,
                GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH) == 0) {
-      if (args->channel_args->args[i].type != GRPC_ARG_INTEGER) {
+      chand->max_recv_size = (size_t)grpc_channel_arg_get_integer(
-        gpr_log(GPR_ERROR, "%s ignored: it must be an integer",
+          &args->channel_args->args[i], options);
-                GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH);
-      } else if (args->channel_args->args[i].value.integer < 0) {
-        gpr_log(GPR_ERROR, "%s ignored: it must be >= 0",
-                GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH);
-      } else {
-        chand->max_recv_size =
-            (size_t)args->channel_args->args[i].value.integer;
-      }
     }
   }
 }