Wire up MVM_HAS_READLINE and --no-readline

Configure.pl

@@ -29,6 +29,7 @@
     cc=s ld=s make=s
     build=s host=s
     big-endian
+    no-readline
 )) or die "See --help for further information\n";
 
 pod2usage(1) if $args{help};
@@ -41,6 +42,8 @@
 $args{instrument} //= 0;
 
 $args{'big-endian'} //= 0;
+# disable GNU Readline
+$args{'no-readline'} //= 0;
 
 # fill in C<%defaults>
 if (exists $args{build} || exists $args{host}) {
@@ -53,6 +56,8 @@
 }
 
 $config{name} = $NAME;
+$config{hasreadline} = 0
+    if $args{'no-readline'};
 
 # set options that take priority over all others
 my @keys = qw( cc ld make );
@@ -122,6 +127,8 @@
     build::auto::detect_native(\%config, \%defaults);
 }
 
+$config{hasreadline} //= 0;
+
 # dump configuration
 print "\n", <<TERM, "\n";
       make: $config{make}
@@ -424,6 +431,7 @@ =head1 SYNOPSIS
                    [--toolchain <toolchain>] [--compiler <compiler>]
                    [--cc <cc>] [--ld <ld>] [--make <make>]
                    [--debug] [--optimize] [--instrument]
+                   [--no-readline]
 
     ./Configure.pl --build <build-triple> --host <host-triple>
                    [--cc <cc>] [--ld <ld>] [--make <make>]
@@ -494,6 +502,12 @@ =head1 OPTIONS
 Explicitly set the make tool without affecting other configuration
 options.
 
+=item --no-readline
+
+Disable GNU Readline auto-detection and force use of Linenoise.
+This flag is important if you create derivative work based on MoarVM
+that you wish to distribute under a license other than the GNU GPL.
+
 =item --build <build-triple> --host <host-triple>
 
 Set up cross-compilation.

build/auto.pm

@@ -33,8 +33,8 @@ sub detect_native {
     }
 
     # detect readline and use it instead of linenoise
-    if ($defaults->{-toolchain} eq 'gnu') {
-        print ::dots('    auto-detecting readline library');
+    if ($defaults->{-toolchain} eq 'gnu' && !defined $config->{hasreadline}) {
+        print ::dots('    auto-detecting GNU readline');
 
         my $cc = $config->{cc};
         qx{echo '#include <readline/readline.h>' | $cc -E - 2>&1};
@@ -43,9 +43,10 @@ sub detect_native {
             print "YES\n";
             $config->{ldlibs} = '-lreadline ' . $config->{ldlibs};
 
-            # TODO: disable linenoise build
-            # print ::dots('    disable linenoise build');
-            # print "OK\n";
+            print ::dots('    disable Linenoise build');
+            $defaults->{-thirdparty}->{ln} = undef;
+            $config->{hasreadline} = 1;
+            print "OK\n";
         }
         else { print "NO\n" }
     }

build/config.h.in

@@ -34,3 +34,6 @@
 
 /* stuff for uthash */
 #define uthash_fatal(msg) MVM_exception_throw_adhoc(tc, "internal hash error: " msg)
+
+/* Readline detection */
+#define MVM_HAS_READLINE @hasreadline@

src/io/fileops.c

@@ -336,6 +336,48 @@ MVMString * MVM_file_readline_fh(MVMThreadContext *tc, MVMObject *oshandle) {
     return result;
 }
 
+/* reads a line from a filehandle. */
+MVMString * MVM_file_readline_interactive_fh(MVMThreadContext *tc, MVMObject *oshandle, MVMString *prompt) {
+    MVMString *return_str = NULL;
+    MVMOSHandle *handle;
+    char *line;
+    char * const prompt_str = MVM_string_utf8_encode_C_string(tc, prompt);
+
+    verify_filehandle_type(tc, oshandle, &handle, "read from filehandle");
+
+#if MVM_HAS_READLINE
+    line = readline(prompt_str);
+
+    free(prompt_str);
+
+    if (line) {
+        if (*line)
+            add_history(line);
+
+        return_str = MVM_decode_C_buffer_to_string(tc, tc->instance->VMString, line, strlen(line), handle->body.encoding_type);
+
+        free(line);
+    }
+
+#else /* !MVM_HAS_READLINE */
+    line = linenoise(prompt_str);
+
+    free(prompt_str);
+
+    if (line) {
+        if (*line) {
+            linenoiseHistoryAdd(line);
+        }
+
+        return_str = MVM_decode_C_buffer_to_string(tc, tc->instance->VMString, line, strlen(line), handle->body.encoding_type);
+
+        free(line);
+    }
+#endif /* MVM_HAS_READLINE */
+
+    return return_str;
+}
+
 /* reads a string from a filehandle. */
 MVMString * MVM_file_read_fhs(MVMThreadContext *tc, MVMObject *oshandle, MVMint64 length) {
     MVMString *result;