[PATCH 14/30] kconfig: support append assignment operator

[Masahiro Yamada]

Support += operator.  This appends a space and the text on the
righthand side to a variable.

The timing of the evaluation of the righthand side depends on the
flavor of the variable.  If the lefthand side was originally defined
as a simple variable, the righthand side is expanded immediately.
Otherwise, the expansion is deferred.  Appending something to an
undefined variable results in a recursive variable.

To implement this, we need to remember the flavor of variables.

Signed-off-by: Masahiro Yamada <yamada.masah...@socionext.com>
---

Changes in v3:
  - newly added

Changes in v2: None

 scripts/kconfig/lkc_proto.h  |  1 +
 scripts/kconfig/preprocess.c | 29 +++++++++++++++++++++++++++--
 scripts/kconfig/zconf.l      |  1 +
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/scripts/kconfig/lkc_proto.h b/scripts/kconfig/lkc_proto.h
index 6303193..a8b7a33 100644
--- a/scripts/kconfig/lkc_proto.h
+++ b/scripts/kconfig/lkc_proto.h
@@ -52,6 +52,7 @@ const char * prop_get_type_name(enum prop_type type);
 enum variable_flavor {
        VAR_SIMPLE,
        VAR_RECURSIVE,
+       VAR_APPEND,
 };
 void env_write_dep(FILE *f, const char *auto_conf_name);
 void variable_add(const char *name, const char *value,
diff --git a/scripts/kconfig/preprocess.c b/scripts/kconfig/preprocess.c
index a835c94..85972fb 100644
--- a/scripts/kconfig/preprocess.c
+++ b/scripts/kconfig/preprocess.c
@@ -86,6 +86,7 @@ static LIST_HEAD(variable_list);
 struct variable {
        char *name;
        char *value;
+       enum variable_flavor flavor;
        struct list_head node;
 };
 
@@ -116,18 +117,42 @@ void variable_add(const char *name, const char *value,
                  enum variable_flavor flavor)
 {
        struct variable *v;
+       char *new_value;
+       bool append = false;
 
        v = variable_lookup(name);
        if (v) {
-               free(v->value);
+               /* For defined variables, += inherits the existing flavor */
+               if (flavor == VAR_APPEND) {
+                       flavor = v->flavor;
+                       append = true;
+               } else {
+                       free(v->value);
+               }
        } else {
+               /* For undefined variables, += assumes the recursive flavor */
+               if (flavor == VAR_APPEND)
+                       flavor = VAR_RECURSIVE;
+
                v = xmalloc(sizeof(*v));
                v->name = xstrdup(name);
                list_add_tail(&v->node, &variable_list);
        }
 
-       v->value = (flavor == VAR_SIMPLE) ? expand_string(value) :
+       v->flavor = flavor;
+
+       new_value = (flavor == VAR_SIMPLE) ? expand_string(value) :
                                                                xstrdup(value);
+
+       if (append) {
+               v->value = xrealloc(v->value,
+                                   strlen(v->value) + strlen(new_value) + 2);
+               strcat(v->value, " ");
+               strcat(v->value, new_value);
+               free(new_value);
+       } else {
+               v->value = new_value;
+       }
 }
 
 static void variable_del(struct variable *v)
diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
index aa76942..c68ca56b 100644
--- a/scripts/kconfig/zconf.l
+++ b/scripts/kconfig/zconf.l
@@ -116,6 +116,7 @@ n   [A-Za-z0-9_-]
        }
        "="     { BEGIN(ASSIGN_VAL); yylval.flavor = VAR_RECURSIVE; return 
T_ASSIGN; }
        ":="    { BEGIN(ASSIGN_VAL); yylval.flavor = VAR_SIMPLE; return 
T_ASSIGN; }
+       "+="    { BEGIN(ASSIGN_VAL); yylval.flavor = VAR_APPEND; return 
T_ASSIGN; }
        [[:blank:]]+
        .       warn_ignored_character(*yytext);
        \n      {
-- 
2.7.4