rules: add include statements to rules files

The majority use-case for extending XKB on a machine is to override one or a
few keys with custom keycodes, not to define whole layouts.

Previously, we relied on the rules file to be a single file, making it hard to
extend. libxkbcommon parses $XDG_CONFIG_HOME/xkb/ but that only works as long
as there is a rule that matches the user-specified RMLVO. This works for MLV
but not for options which don't have a wildcard defined. Users have to copy
the whole rules file and then work from there - not something easy to extend
and maintain.

This patch adds a new ! include directive to rules files that allows including
another file. The file path must be without quotes and may not start with the
literal "include". Two directives are supported, %H to $HOME and %S for the
system-installed rules directory (usually /usr/share/X11/xkb/rules).

A user would typically use a custom rules file like this:

! option                =       symbols
  custom:foo            =       +custom(foo)
  custom:bar            =       +custom(baz)

! include %S/evdev

Where the above defines the two options and then includes the system-installed
evdev rule. Since most current implementations default to loading the "evdev"
ruleset, it's best to name this $XDG_CONFIG_HOME/xkb/rules/evdev, but any
valid name is allowed.

The include functionally replaces the line with the content of the included
file which means the behavior of rules files is maintained. Specifically,
custom options must be defined before including another file because the first
match usually wins. In other words, the following ruleset will not assign
my_model as one would expect:

! include %S/evdev

! model                 =  symbols
  my_model              =  +custom(foo)

The default evdev ruleset has wildcards for model and those match before the
my_model is hit.

The actual resolved components need only be in one of the XKB lookup
directories, e.g. for the example above:

$ cat $XDG_CONFIG_HOME/xkb/symbols/custom
partial alphanumeric_keys
xkb_symbols "foo" {
    key <TLDE> {        [      VoidSymbol ]       };
};

partial alphanumeric_keys
xkb_symbols "baz" {
    key <AB01> {        [      k, K ]       };
};

This can then be loaded with the XKB option "custom:foo,custom:bar".

The use of "custom" is just as an example, there are no naming requirements
beyond avoiding already-used ones. Also note the bar/baz above - the option
names don't have to match the component names.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

9 files changed, 228 insertions, 0 deletions

diff --git a/test/data/rules/inc-dst-loop-twice b/test/data/rules/inc-dst-loop-twice
new file mode 100644
index 0000000..abb11b0
--- /dev/null
+++ b/test/data/rules/inc-dst-loop-twice
@@ -0,0 +1,20 @@
+! model         = keycodes
+  *             = default_keycodes
+
+! layout        variant    = symbols
+  my_layout     my_variant = my_symbols+extra_variant
+
+! layout        = symbols
+  my_layout     = my_symbols
+  *             = default_symbols
+
+! model         = types
+  *             = default_types
+
+! model         = compat
+  *             = default_compat
+
+! option        = compat
+  my_option     = |some:compat
+
+! include %S/inc-src-loop-twice
diff --git a/test/data/rules/inc-dst-simple b/test/data/rules/inc-dst-simple
new file mode 100644
index 0000000..a8d0605
--- /dev/null
+++ b/test/data/rules/inc-dst-simple
@@ -0,0 +1,18 @@
+! model         = keycodes
+  my_model      = my_keycodes
+  *             = default_keycodes
+
+! layout        variant    = symbols
+  my_layout     my_variant = my_symbols+extra_variant
+
+! layout        = symbols
+  *             = default_symbols
+
+! model         = types
+  *             = default_types
+
+! model         = compat
+  *             = default_compat
+
+! option        = compat
+  my_option     = |some:compat
diff --git a/test/data/rules/inc-src-before-after b/test/data/rules/inc-src-before-after
new file mode 100644
index 0000000..6ea34f0
--- /dev/null
+++ b/test/data/rules/inc-src-before-after
@@ -0,0 +1,7 @@
+! model         = keycodes
+  before_model  = my_keycodes
+
+! include %S/inc-dst-simple
+
+! layout        = symbols
+  after_layout  = my_symbols
diff --git a/test/data/rules/inc-src-loop-twice b/test/data/rules/inc-src-loop-twice
new file mode 100644
index 0000000..67e66c1
--- /dev/null
+++ b/test/data/rules/inc-src-loop-twice
@@ -0,0 +1,4 @@
+! model         = keycodes
+  my_model      = my_keycodes
+
+! include %S/inc-dst-loop-twice
diff --git a/test/data/rules/inc-src-looped b/test/data/rules/inc-src-looped
new file mode 100644
index 0000000..652abdd
--- /dev/null
+++ b/test/data/rules/inc-src-looped
@@ -0,0 +1 @@
+! include %S/inc-src-looped
diff --git a/test/data/rules/inc-src-nested b/test/data/rules/inc-src-nested
new file mode 100644
index 0000000..7f23207
--- /dev/null
+++ b/test/data/rules/inc-src-nested
@@ -0,0 +1 @@
+! include %S/inc-src-simple
diff --git a/test/data/rules/inc-src-options b/test/data/rules/inc-src-options
new file mode 100644
index 0000000..6fa13ec
--- /dev/null
+++ b/test/data/rules/inc-src-options
@@ -0,0 +1,10 @@
+! option        = compat
+  option111     = +substring
+  option1       = +some:compat
+  option11      = +group(bla)
+
+! include %S/inc-dst-simple
+
+! option        = symbols
+  option3       = +compose(foo)+keypad(bar)
+  colon:opt     = +altwin(menu)
diff --git a/test/data/rules/inc-src-simple b/test/data/rules/inc-src-simple
new file mode 100644
index 0000000..afe4742
--- /dev/null
+++ b/test/data/rules/inc-src-simple
@@ -0,0 +1,4 @@
+! layout        = symbols
+  my_layout     = my_symbols
+
+! include %S/inc-dst-simple
diff --git a/test/rules-file-includes.c b/test/rules-file-includes.c
new file mode 100644
index 0000000..bdeb03a
--- /dev/null
+++ b/test/rules-file-includes.c
@@ -0,0 +1,163 @@
+/*
+ * Copyright © 2012 Ran Benita <ran234@gmail.com>
+ * Copyright © 2019 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "test-config.h"
+
+#include "test.h"
+#include "xkbcomp/xkbcomp-priv.h"
+#include "xkbcomp/rules.h"
+
+struct test_data {
+    /* Rules file */
+    const char *rules;
+
+    /* Input */
+    const char *model;
+    const char *layout;
+    const char *variant;
+    const char *options;
+
+    /* Expected output */
+    const char *keycodes;
+    const char *types;
+    const char *compat;
+    const char *symbols;
+
+    /* Or set this if xkb_components_from_rules() should fail. */
+    bool should_fail;
+};
+
+static bool
+test_rules(struct xkb_context *ctx, struct test_data *data)
+{
+    bool passed;
+    const struct xkb_rule_names rmlvo = {
+        data->rules, data->model, data->layout, data->variant, data->options
+    };
+    struct xkb_component_names kccgst;
+
+    fprintf(stderr, "\n\nChecking : %s\t%s\t%s\t%s\t%s\n", data->rules,
+            data->model, data->layout, data->variant, data->options);
+
+    if (data->should_fail)
+        fprintf(stderr, "Expecting: FAILURE\n");
+    else
+        fprintf(stderr, "Expecting: %s\t%s\t%s\t%s\n",
+                data->keycodes, data->types, data->compat, data->symbols);
+
+    if (!xkb_components_from_rules(ctx, &rmlvo, &kccgst)) {
+        fprintf(stderr, "Received : FAILURE\n");
+        return data->should_fail;
+    }
+
+    fprintf(stderr, "Received : %s\t%s\t%s\t%s\n",
+            kccgst.keycodes, kccgst.types, kccgst.compat, kccgst.symbols);
+
+    passed = streq(kccgst.keycodes, data->keycodes) &&
+             streq(kccgst.types, data->types) &&
+             streq(kccgst.compat, data->compat) &&
+             streq(kccgst.symbols, data->symbols);
+
+    free(kccgst.keycodes);
+    free(kccgst.types);
+    free(kccgst.compat);
+    free(kccgst.symbols);
+
+    return passed;
+}
+
+int
+main(int argc, char *argv[])
+{
+    struct xkb_context *ctx;
+
+    setenv("XKB_CONFIG_ROOT", TEST_XKB_CONFIG_ROOT, 1);
+
+    ctx = test_get_context(0);
+    assert(ctx);
+
+    struct test_data test1 = {
+        .rules = "inc-src-simple",
+
+        .model = "my_model", .layout = "my_layout", .variant = "", .options = "",
+
+        .keycodes = "my_keycodes", .types = "default_types",
+        .compat = "default_compat", .symbols = "my_symbols",
+    };
+    assert(test_rules(ctx, &test1));
+
+    struct test_data test2 = {
+        .rules = "inc-src-nested",
+
+        .model = "my_model", .layout = "my_layout", .variant = "", .options = "",
+
+        .keycodes = "my_keycodes", .types = "default_types",
+        .compat = "default_compat", .symbols = "my_symbols",
+    };
+    assert(test_rules(ctx, &test2));
+
+    struct test_data test3 = {
+        .rules = "inc-src-looped",
+
+        .model = "my_model", .layout = "my_layout", .variant = "", .options = "",
+
+        .should_fail = true,
+    };
+    assert(test_rules(ctx, &test3));
+
+    struct test_data test4 = {
+        .rules = "inc-src-before-after",
+
+        .model = "before_model", .layout = "my_layout", .variant = "", .options = "",
+
+        .keycodes = "my_keycodes", .types = "default_types",
+        .compat = "default_compat", .symbols = "default_symbols",
+    };
+    assert(test_rules(ctx, &test4));
+
+    struct test_data test5 = {
+        .rules = "inc-src-options",
+
+        .model = "my_model", .layout = "my_layout", .variant = "my_variant",
+        .options = "option11,my_option,colon:opt,option111",
+
+        .keycodes = "my_keycodes", .types = "default_types",
+        .compat = "default_compat+substring+group(bla)|some:compat",
+        .symbols = "my_symbols+extra_variant+altwin(menu)",
+    };
+    assert(test_rules(ctx, &test5));
+
+    struct test_data test6 = {
+        .rules = "inc-src-loop-twice",
+
+        .model = "my_model", .layout = "my_layout", .variant = "", .options = "",
+
+        .keycodes = "my_keycodes", .types = "default_types",
+        .compat = "default_compat", .symbols = "my_symbols",
+    };
+    assert(test_rules(ctx, &test6));
+
+    xkb_context_unref(ctx);
+    return 0;
+}