Add grpc_channel_arg_get_integer() utility function.

3 files changed, 34 insertions, 20 deletions

diff --git a/src/core/lib/channel/channel_args.c b/src/core/lib/channel/channel_args.c
index 79ceeb66b3..3a56b1ff20 100644
--- a/src/core/lib/channel/channel_args.c
+++ b/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;
+}
diff --git a/src/core/lib/channel/channel_args.h b/src/core/lib/channel/channel_args.h
index aec61ee7c6..71fde5ad7e 100644
--- a/src/core/lib/channel/channel_args.h
+++ b/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 */
diff --git a/src/core/lib/channel/message_size_filter.c b/src/core/lib/channel/message_size_filter.c
index 10cb1998d1..ee9e3ee734 100644
--- a/src/core/lib/channel/message_size_filter.c
+++ b/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) {
-        gpr_log(GPR_ERROR, "%s ignored: it must be an integer",
-                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;
-      }
+      chand->max_send_size = (size_t)grpc_channel_arg_get_integer(
+          &args->channel_args->args[i], options);
     }
     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) {
-        gpr_log(GPR_ERROR, "%s ignored: it must be an integer",
-                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;
-      }
+      chand->max_recv_size = (size_t)grpc_channel_arg_get_integer(
+          &args->channel_args->args[i], options);
     }
   }
 }