lib9p: Don't copy byte-arrays when unmarshaling

1 files changed, 12 insertions, 7 deletions

diff --git a/lib9p/idl.gen b/lib9p/idl.gen
index 9a8260a..f2b4f13 100755
--- a/lib9p/idl.gen
+++ b/lib9p/idl.gen
@@ -831,7 +831,10 @@ LM_ALWAYS_INLINE static bool validate_8(struct _validate_ctx *ctx) { return _val
                     if member.in_versions != typ.in_versions:
                         ret += "( " + c_ver_cond(member.in_versions) + " && "
                     if member.cnt is not None:
-                        ret += f"_validate_list(ctx, {member.cnt.name}, validate_{member.typ.name}, sizeof({c_typename(member.typ)}))"
+                        if member.typ.static_size == 1:  # SPECIAL (zerocopy)
+                            ret += f"_validate_size_net(ctx, {member.cnt.name})"
+                        else:
+                            ret += f"_validate_list(ctx, {member.cnt.name}, validate_{member.typ.name}, sizeof({c_typename(member.typ)}))"
                         if typ.name == "s":  # SPECIAL (string)
                             ret += f'\n\t    || ({{ (!is_valid_utf8_without_nul(&ctx->net_bytes[ctx->net_offset-len], len)) && lib9p_error(ctx->ctx, LINUX_EBADMSG, "message contains invalid UTF-8"); }})'
                     else:
@@ -935,13 +938,15 @@ LM_ALWAYS_INLINE static void unmarshal_8(struct _unmarshal_ctx *ctx, uint64_t *o
                         if member.in_versions != typ.in_versions:
                             ret += "{\n"
                             ret += prefix
-                        ret += f"out->{member.name} = ctx->extra;\n"
-                        ret += f"{prefix}ctx->extra += sizeof(out->{member.name}[0]) * out->{member.cnt.name};\n"
-                        ret += f"{prefix}for (typeof(out->{member.cnt.name}) i = 0; i < out->{member.cnt.name}; i++)\n"
-                        if member.typ.static_size == 1:  # SPECIAL (string)
-                            # Special-case is that we cast from `char` to `uint8_t`.
-                            ret += f"{prefix}\tunmarshal_{member.typ.name}(ctx, (uint8_t *)&out->{member.name}[i]);\n"
+                        if member.typ.static_size == 1:  # SPECIAL (string, zerocopy)
+                            ret += f"out->{member.name} = (char *)&ctx->net_bytes[ctx->net_offset];\n"
+                            ret += (
+                                f"{prefix}ctx->net_offset += out->{member.cnt.name};\n"
+                            )
                         else:
+                            ret += f"out->{member.name} = ctx->extra;\n"
+                            ret += f"{prefix}ctx->extra += sizeof(out->{member.name}[0]) * out->{member.cnt.name};\n"
+                            ret += f"{prefix}for (typeof(out->{member.cnt.name}) i = 0; i < out->{member.cnt.name}; i++)\n"
                             ret += f"{prefix}\tunmarshal_{member.typ.name}(ctx, &out->{member.name}[i]);\n"
                         if member.in_versions != typ.in_versions:
                             ret += "\t}\n"