ref-filter: implement %(if:equals=<string>) and %(if:notequals=<string>)

Implement %(if:equals=<string>) wherein the if condition is only
satisfied if the value obtained between the %(if:...) and %(then) atom
is the same as the given '<string>'.

Similarly, implement (if:notequals=<string>) wherein the if condition
is only satisfied if the value obtained between the %(if:...) and
%(then) atom is different from the given '<string>'.

This is done by introducing 'if_atom_parser()' which parses the given
%(if) atom and then stores the data in used_atom which is later passed
on to the used_atom of the %(then) atom, so that it can do the required
comparisons.

Add tests and documentation for the same.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 6b671ae..d5be419 100644 (file)
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -158,6 +158,9 @@ if::
        evaluating the string before %(then), this is useful when we
        use the %(HEAD) atom which prints either "*" or " " and we
        want to apply the 'if' condition only on the 'HEAD' ref.
+       Append ":equals=<string>" or ":notequals=<string>" to compare
+       the value between the %(if:...) and %(then) atoms with the
+       given string.
 
 In addition to the above, for commit and tag objects, the header
 field names (`tree`, `parent`, `object`, `type`, and `tag`) can

diff --git a/ref-filter.c b/ref-filter.c
index f31c4b6..302bb2d 100644 (file)
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -16,6 +16,7 @@
 #include "trailer.h"
 
 typedef enum { FIELD_STR, FIELD_ULONG, FIELD_TIME } cmp_type;
+typedef enum { COMPARE_EQUAL, COMPARE_UNEQUAL, COMPARE_NONE } cmp_status;
 
 struct align {
        align_type position;
@@ -23,6 +24,8 @@ struct align {
 };
 
 struct if_then_else {
+       cmp_status cmp_status;
+       const char *str;
        unsigned int then_atom_seen : 1,
                else_atom_seen : 1,
                condition_satisfied : 1;
@@ -50,6 +53,10 @@ static struct used_atom {
                        enum { C_BARE, C_BODY, C_BODY_DEP, C_LINES, C_SIG, C_SUB, C_TRAILERS } option;
                        unsigned int nlines;
                } contents;
+               struct {
+                       cmp_status cmp_status;
+                       const char *str;
+               } if_then_else;
                enum { O_FULL, O_SHORT } objectname;
        } u;
 } *used_atom;
@@ -179,6 +186,21 @@ static void align_atom_parser(struct used_atom *atom, const char *arg)
        string_list_clear(&params, 0);
 }
 
+static void if_atom_parser(struct used_atom *atom, const char *arg)
+{
+       if (!arg) {
+               atom->u.if_then_else.cmp_status = COMPARE_NONE;
+               return;
+       } else if (skip_prefix(arg, "equals=", &atom->u.if_then_else.str)) {
+               atom->u.if_then_else.cmp_status = COMPARE_EQUAL;
+       } else if (skip_prefix(arg, "notequals=", &atom->u.if_then_else.str)) {
+               atom->u.if_then_else.cmp_status = COMPARE_UNEQUAL;
+       } else {
+               die(_("unrecognized %%(if) argument: %s"), arg);
+       }
+}
+
+
 static struct {
        const char *name;
        cmp_type cmp_type;
@@ -220,7 +242,7 @@ static struct {
        { "color", FIELD_STR, color_atom_parser },
        { "align", FIELD_STR, align_atom_parser },
        { "end" },
-       { "if" },
+       { "if", FIELD_STR, if_atom_parser },
        { "then" },
        { "else" },
 };
@@ -422,6 +444,9 @@ static void if_atom_handler(struct atom_value *atomv, struct ref_formatting_stat
        struct ref_formatting_stack *new;
        struct if_then_else *if_then_else = xcalloc(sizeof(struct if_then_else), 1);
 
+       if_then_else->str = atomv->atom->u.if_then_else.str;
+       if_then_else->cmp_status = atomv->atom->u.if_then_else.cmp_status;
+
        push_stack_element(&state->stack);
        new = state->stack;
        new->at_end = if_then_else_handler;
@@ -453,10 +478,17 @@ static void then_atom_handler(struct atom_value *atomv, struct ref_formatting_st
                die(_("format: %%(then) atom used after %%(else)"));
        if_then_else->then_atom_seen = 1;
        /*
-        * If there exists non-empty string between the 'if' and
-        * 'then' atom then the 'if' condition is satisfied.
+        * If the 'equals' or 'notequals' attribute is used then
+        * perform the required comparison. If not, only non-empty
+        * strings satisfy the 'if' condition.
         */
-       if (cur->output.len && !is_empty(cur->output.buf))
+       if (if_then_else->cmp_status == COMPARE_EQUAL) {
+               if (!strcmp(if_then_else->str, cur->output.buf))
+                       if_then_else->condition_satisfied = 1;
+       } else if (if_then_else->cmp_status == COMPARE_UNEQUAL) {
+               if (strcmp(if_then_else->str, cur->output.buf))
+                       if_then_else->condition_satisfied = 1;
+       } else if (cur->output.len && !is_empty(cur->output.buf))
                if_then_else->condition_satisfied = 1;
        strbuf_reset(&cur->output);
 }
@@ -1158,7 +1190,11 @@ static void populate_value(struct ref_array_item *ref)
                } else if (!strcmp(name, "end")) {
                        v->handler = end_atom_handler;
                        continue;
-               } else if (!strcmp(name, "if")) {
+               } else if (starts_with(name, "if")) {
+                       const char *s;
+
+                       if (skip_prefix(name, "if:", &s))
+                               v->s = xstrdup(s);
                        v->handler = if_atom_handler;
                        continue;
                } else if (!strcmp(name, "then")) {

diff --git a/t/t6302-for-each-ref-filter.sh b/t/t6302-for-each-ref-filter.sh
index fed3013..a09a1a4 100755 (executable)
--- a/t/t6302-for-each-ref-filter.sh
+++ b/t/t6302-for-each-ref-filter.sh
@@ -403,4 +403,22 @@ test_expect_success 'ignore spaces in %(if) atom usage' '
        test_cmp expect actual
 '
 
+test_expect_success 'check %(if:equals=<string>)' '
+       git for-each-ref --format="%(if:equals=master)%(refname:short)%(then)Found master%(else)Not master%(end)" refs/heads/ >actual &&
+       cat >expect <<-\EOF &&
+       Found master
+       Not master
+       EOF
+       test_cmp expect actual
+'
+
+test_expect_success 'check %(if:notequals=<string>)' '
+       git for-each-ref --format="%(if:notequals=master)%(refname:short)%(then)Not master%(else)Found master%(end)" refs/heads/ >actual &&
+       cat >expect <<-\EOF &&
+       Found master
+       Not master
+       EOF
+       test_cmp expect actual
+'
+
 test_done