Move the 'git_attr_set_direction()' up to be closer to the variables
that it modifies as well as a small formatting by renaming the variable
'new' to 'new_direction' so that it is more descriptive.
Update the comment about how 'direction' is used to read the state of
the world. It should be noted that callers of
'git_attr_set_direction()' should ensure that other threads are not
making calls into the attribute system until after the call to
'git_attr_set_direction()' completes. This function essentially acts as
reset button for the attribute system and should be handled with care.
Signed-off-by: Brandon Williams <bmwill@xxxxxxxxxx>
---
attr.c | 49 ++++++++++++++++++++-----------------------------
attr.h | 3 ++-
2 files changed, 22 insertions(+), 30 deletions(-)
diff --git a/attr.c b/attr.c
index c2ea5cb29..f35c1107f 100644
--- a/attr.c
+++ b/attr.c
@@ -578,26 +578,30 @@ static struct attr_stack *read_attr_from_array(const char **list)
}
/*
- * NEEDSWORK: these two are tricky. The callers assume there is a
- * single, system-wide global state "where we read attributes from?"
- * and when the state is flipped by calling git_attr_set_direction(),
- * attr_stack is discarded so that subsequent attr_check will lazily
- * read from the right place. And they do not know or care who called
- * by them uses the attribute subsystem, hence have no knowledge of
- * existing git_attr_check instances or future ones that will be
- * created).
- *
- * Probably we need a thread_local that holds these two variables,
- * and a list of git_attr_check instances (which need to be maintained
- * by hooking into git_attr_check_alloc(), git_attr_check_initl(), and
- * git_attr_check_clear(). Then git_attr_set_direction() updates the
- * fields in that thread_local for these two variables, iterate over
- * all the active git_attr_check instances and discard the attr_stack
- * they hold. Yuck, but it sounds doable.
+ * Callers into the attribute system assume there is a single, system-wide
+ * global state where attributes are read from and when the state is flipped by
+ * calling git_attr_set_direction(), the stack frames that have been
+ * constructed need to be discarded so so that subsequent calls into the
+ * attribute system will lazily read from the right place. Since changing
+ * direction causes a global paradigm shift, it should not ever be called while
+ * another thread could potentially be calling into the attribute system.
*/
static enum git_attr_direction direction;
static struct index_state *use_index;
+void git_attr_set_direction(enum git_attr_direction new_direction,
+ struct index_state *istate)
+{
+ if (is_bare_repository() && new_direction != GIT_ATTR_INDEX)
+ die("BUG: non-INDEX attr direction in a bare repo");
+
+ if (new_direction != direction)
+ drop_attr_stack();
+
+ direction = new_direction;
+ use_index = istate;
+}
+
static struct attr_stack *read_attr_from_file(const char *path, int macro_ok)
{
FILE *fp = fopen(path, "r");
@@ -1132,19 +1136,6 @@ void attr_check_free(struct attr_check *check)
}
}
-void git_attr_set_direction(enum git_attr_direction new, struct index_state *istate)
-{
- enum git_attr_direction old = direction;
-
- if (is_bare_repository() && new != GIT_ATTR_INDEX)
- die("BUG: non-INDEX attr direction in a bare repo");
-
- direction = new;
- if (new != old)
- drop_attr_stack();
- use_index = istate;
-}
-
void attr_start(void)
{
#ifndef NO_PTHREADS
diff --git a/attr.h b/attr.h
index da7c3a229..62dbcb6b8 100644
--- a/attr.h
+++ b/attr.h
@@ -76,7 +76,8 @@ enum git_attr_direction {
GIT_ATTR_CHECKOUT,
GIT_ATTR_INDEX
};
-void git_attr_set_direction(enum git_attr_direction, struct index_state *);
+void git_attr_set_direction(enum git_attr_direction new_direction,
+ struct index_state *istate);
extern void attr_start(void);
--
2.11.0.483.g087da7b7c-goog