Cleanup: Use enum for return values in context callbacks

Define enum `eContextResult` and use its values for returns, instead of
just returning 1, 0, or -1 (and always having some comment that explains
what -1 means).

This also cleans up the mixup between returning `0` and `false`, and `1`
and `true`. An inconsistency was discovered during this cleanup, and
marked with `TODO(sybren)`. It's not fixed here, as it would consititute
a functional change.

The enum isn't used everywhere, as enums in C and C++ can have different
storage sizes. To prevent issues, callback functions are still declared
as returning`int`. To at least make things easier to understand for
humans, I marked those with `int /*eContextResult*/`.

This is a followup of D9090, and is intended to unify how context
callbacks return values. This will make it easier to extend the approach
in D9090 to those functions.

No functional changes.

Differential Revision: https://developer.blender.org/D9095

1 files changed, 9 insertions, 10 deletions

diff --git a/source/blender/blenkernel/intern/context.c b/source/blender/blenkernel/intern/context.c
index 17ac8d7bedc..2002a49293f 100644
--- a/source/blender/blenkernel/intern/context.c
+++ b/source/blender/blenkernel/intern/context.c
@@ -294,7 +294,7 @@ static void *ctx_wm_python_context_get(const bContext *C,
   return fall_through;
 }
 
-static int ctx_data_get(bContext *C, const char *member, bContextDataResult *result)
+static eContextResult ctx_data_get(bContext *C, const char *member, bContextDataResult *result)
 {
   bScreen *screen;
   ScrArea *area;
@@ -374,7 +374,7 @@ static void *ctx_data_pointer_get(const bContext *C, const char *member)
 {
   bContextDataResult result;
 
-  if (C && ctx_data_get((bContext *)C, member, &result) == 1) {
+  if (C && ctx_data_get((bContext *)C, member, &result) == CTX_RESULT_OK) {
     BLI_assert(result.type == CTX_DATA_TYPE_POINTER);
     return result.ptr.data;
   }
@@ -391,7 +391,7 @@ static int ctx_data_pointer_verify(const bContext *C, const char *member, void *
     *pointer = NULL;
     return 1;
   }
-  if (ctx_data_get((bContext *)C, member, &result) == 1) {
+  if (ctx_data_get((bContext *)C, member, &result) == CTX_RESULT_OK) {
     BLI_assert(result.type == CTX_DATA_TYPE_POINTER);
     *pointer = result.ptr.data;
     return 1;
@@ -405,7 +405,7 @@ static int ctx_data_collection_get(const bContext *C, const char *member, ListBa
 {
   bContextDataResult result;
 
-  if (ctx_data_get((bContext *)C, member, &result) == 1) {
+  if (ctx_data_get((bContext *)C, member, &result) == CTX_RESULT_OK) {
     BLI_assert(result.type == CTX_DATA_TYPE_COLLECTION);
     *list = result.list;
     return 1;
@@ -453,7 +453,7 @@ PointerRNA CTX_data_pointer_get(const bContext *C, const char *member)
 {
   bContextDataResult result;
 
-  if (ctx_data_get((bContext *)C, member, &result) == 1) {
+  if (ctx_data_get((bContext *)C, member, &result) == CTX_RESULT_OK) {
     BLI_assert(result.type == CTX_DATA_TYPE_POINTER);
     return result.ptr;
   }
@@ -495,7 +495,7 @@ ListBase CTX_data_collection_get(const bContext *C, const char *member)
 {
   bContextDataResult result;
 
-  if (ctx_data_get((bContext *)C, member, &result) == 1) {
+  if (ctx_data_get((bContext *)C, member, &result) == CTX_RESULT_OK) {
     BLI_assert(result.type == CTX_DATA_TYPE_COLLECTION);
     return result.list;
   }
@@ -504,14 +504,13 @@ ListBase CTX_data_collection_get(const bContext *C, const char *member)
   return list;
 }
 
-/* 1:found,  -1:found but not set,  0:not found */
-int CTX_data_get(
+int /*eContextResult*/ CTX_data_get(
     const bContext *C, const char *member, PointerRNA *r_ptr, ListBase *r_lb, short *r_type)
 {
   bContextDataResult result;
-  int ret = ctx_data_get((bContext *)C, member, &result);
+  eContextResult ret = ctx_data_get((bContext *)C, member, &result);
 
-  if (ret == 1) {
+  if (ret == CTX_RESULT_OK) {
     *r_ptr = result.ptr;
     *r_lb = result.list;
     *r_type = result.type;