Make Object_Compare functions accept third argument

Explorer09 · Explorer09 · commit 71980710d596 · 2025-11-15T01:44:10.000+08:00
Update the prototypes of all Object_Compare functions and Vector_sort()
function to accept the third argument.

The third argument allows passing in extra information or states that
could be useful in sorting. The definition of Object_Compare now matches
the prototype of the compare function in libc qsort_r().

(Previously many programmers would use global variables to read or store
extra information needed in a compare operation. This made the sort
function not reentrant. It was the primary motivation for the qsort_r()
function.)

Currently all Object_Compare functions in htop would simply the third
argument. No functions are using it yet, but this may be changed in the
future.

The callers of Vector_sort() will now by default pass in the reference
of the container object (usually named "this") as the third argument to
the sort compare functions.

Signed-off-by: Kang-Che Sung &lt;explorer09@gmail.com&gt;
diff --git a/Action.c b/Action.c
@@ -542,7 +542,7 @@ static Htop_Reaction actionFilterByUser(State* st) {
    Panel_setHeader(usersPanel, "Show processes of:");
    Machine* host = st->host;
    UsersTable_foreach(host->usersTable, addUserToVector, usersPanel);
-   Vector_sort(usersPanel->items, NULL);
+   Vector_sort(usersPanel->items, NULL, usersPanel);
    ListItem* allUsers = ListItem_new("All users", -1);
    Panel_insert(usersPanel, 0, (Object*) allUsers);
    const ListItem* picked = (ListItem*) Action_pickFromVector(st, usersPanel, 19, false);
diff --git a/EnvScreen.c b/EnvScreen.c
@@ -52,8 +52,8 @@ static void EnvScreen_scan(InfoScreen* this) {
       InfoScreen_addLine(this, "Could not read process environment.");
    }
 
-   Vector_sort(this->lines, NULL);
-   Vector_sort(panel->items, NULL);
+   Vector_sort(this->lines, NULL, this);
+   Vector_sort(panel->items, NULL, this);
    Panel_setSelected(panel, idx);
 }
 
diff --git a/ListItem.c b/ListItem.c
@@ -59,7 +59,8 @@ void ListItem_append(ListItem* this, const char* text) {
    this->value[newLen] = '\0';
 }
 
-int ListItem_compare(const void* cast1, const void* cast2) {
+int ListItem_compare(const void* cast1, const void* cast2, void* context) {
+   (void)context;
    const ListItem* obj1 = (const ListItem*) cast1;
    const ListItem* obj2 = (const ListItem*) cast2;
    return strcmp(obj1->value, obj2->value);
diff --git a/ListItem.h b/ListItem.h
@@ -32,7 +32,7 @@ ListItem* ListItem_new(const char* value, int key);
 
 void ListItem_append(ListItem* this, const char* text);
 
-int ListItem_compare(const void* cast1, const void* cast2);
+int ListItem_compare(const void* cast1, const void* cast2, void* context);
 
 static inline const char* ListItem_getRef(const ListItem* this) {
    return this->value;
diff --git a/Object.h b/Object.h
@@ -19,7 +19,7 @@ struct Object_;
 typedef struct Object_ Object;
 
 typedef void(*Object_Display)(const Object*, RichString*);
-typedef int(*Object_Compare)(const void*, const void*);
+typedef int(*Object_Compare)(const void*, const void*, void*);
 typedef void(*Object_Delete)(Object*);
 
 #define Object_getClass(obj_)         ((const Object*)(obj_))->klass
@@ -28,7 +28,7 @@ typedef void(*Object_Delete)(Object*);
 #define Object_delete(obj_)           (assert(Object_getClass(obj_)->delete), Object_getClass(obj_)->delete((Object*)(obj_)))
 #define Object_displayFn(obj_)        Object_getClass(obj_)->display
 #define Object_display(obj_, str_)    (assert(Object_getClass(obj_)->display), Object_getClass(obj_)->display((const Object*)(obj_), str_))
-#define Object_compare(obj_, other_)  (assert(Object_getClass(obj_)->compare), Object_getClass(obj_)->compare((const void*)(obj_), other_))
+#define Object_compare(obj_, other_, ctx_)  (assert(Object_getClass(obj_)->compare), Object_getClass(obj_)->compare((const void*)(obj_), other_, ctx_)
 
 #define Class(class_)                 ((const ObjectClass*)(&(class_ ## _class)))
 
diff --git a/OpenFilesScreen.c b/OpenFilesScreen.c
@@ -300,8 +300,8 @@ static void OpenFilesScreen_scan(InfoScreen* super) {
       OpenFiles_Data_clear(&pdata->data);
    }
    free(pdata);
-   Vector_sort(super->lines, NULL);
-   Vector_sort(panel->items, NULL);
+   Vector_sort(super->lines, NULL, super);
+   Vector_sort(panel->items, NULL, super);
    Panel_setSelected(panel, idx);
 }
 
diff --git a/Process.c b/Process.c
@@ -911,7 +911,8 @@ bool Process_rowSendSignal(Row* super, Arg sgn) {
    return Process_sendSignal(this, sgn);
 }
 
-int Process_compare(const void* v1, const void* v2) {
+int Process_compare(const void* v1, const void* v2, void* context) {
+   (void)context;
    const Process* p1 = (const Process*)v1;
    const Process* p2 = (const Process*)v2;
 
@@ -928,7 +929,7 @@ int Process_compare(const void* v1, const void* v2) {
    return (ScreenSettings_getActiveDirection(ss) == 1) ? result : -result;
 }
 
-int Process_compareByParent(const Row* r1, const Row* r2) {
+int Process_compareByParent(const Row* r1, const Row* r2, void* context) {
    int result = SPACESHIP_NUMBER(
       r1->isRoot ? 0 : Row_getGroupOrParent(r1),
       r2->isRoot ? 0 : Row_getGroupOrParent(r2)
@@ -937,7 +938,7 @@ int Process_compareByParent(const Row* r1, const Row* r2) {
    if (result != 0)
       return result;
 
-   return Process_compare(r1, r2);
+   return Process_compare(r1, r2, context);
 }
 
 int Process_compareByKey_Base(const Process* p1, const Process* p2, ProcessField key) {
diff --git a/Process.h b/Process.h
@@ -231,8 +231,8 @@ typedef int32_t ProcessField;  /* see ReservedField list in RowField.h */
 
 // Implemented in platform-specific code:
 void Process_writeField(const Process* this, RichString* str, ProcessField field);
-int Process_compare(const void* v1, const void* v2);
-int Process_compareByParent(const Row* r1, const Row* r2);
+int Process_compare(const void* v1, const void* v2, void* context);
+int Process_compareByParent(const Row* r1, const Row* r2, void* context);
 void Process_delete(Object* cast);
 extern const ProcessFieldData Process_fields[LAST_PROCESSFIELD];
 #define Process_pidDigits Row_pidDigits
@@ -317,8 +317,8 @@ bool Process_rowIsVisible(const Row* super, const struct Table_* table);
 
 bool Process_rowMatchesFilter(const Row* super, const struct Table_* table);
 
-static inline int Process_pidEqualCompare(const void* v1, const void* v2) {
-   return Row_idEqualCompare(v1, v2);
+static inline int Process_pidEqualCompare(const void* v1, const void* v2, void* context) {
+   return Row_idEqualCompare(v1, v2, context);
 }
 
 int Process_compareByKey_Base(const Process* p1, const Process* p2, ProcessField key);
diff --git a/ProcessLocksScreen.c b/ProcessLocksScreen.c
@@ -91,8 +91,8 @@ static void ProcessLocksScreen_scan(InfoScreen* this) {
       }
    }
    free(pdata);
-   Vector_sort(this->lines, NULL);
-   Vector_sort(panel->items, NULL);
+   Vector_sort(this->lines, NULL, this);
+   Vector_sort(panel->items, NULL, this);
    Panel_setSelected(panel, idx);
 }
 
diff --git a/Row.c b/Row.c
@@ -530,14 +530,15 @@ void Row_toggleTag(Row* this) {
    this->tag = !this->tag;
 }
 
-int Row_compare(const void* v1, const void* v2) {
+int Row_compare(const void* v1, const void* v2, void* context) {
+   (void)context;
    const Row* r1 = (const Row*)v1;
    const Row* r2 = (const Row*)v2;
 
    return SPACESHIP_NUMBER(r1->id, r2->id);
 }
 
-int Row_compareByParent_Base(const void* v1, const void* v2) {
+int Row_compareByParent_Base(const void* v1, const void* v2, void* context) {
    const Row* r1 = (const Row*)v1;
    const Row* r2 = (const Row*)v2;
 
@@ -549,7 +550,7 @@ int Row_compareByParent_Base(const void* v1, const void* v2) {
    if (result != 0)
       return result;
 
-   return Row_compare(v1, v2);
+   return Row_compare(v1, v2, context);
 }
 
 const RowClass Row_class = {
diff --git a/Row.h b/Row.h
@@ -82,9 +82,9 @@ typedef bool (*Row_IsHighlighted)(const Row*);
 typedef bool (*Row_IsVisible)(const Row*, const struct Table_*);
 typedef bool (*Row_MatchesFilter)(const Row*, const struct Table_*);
 typedef const char* (*Row_SortKeyString)(Row*);
-typedef int (*Row_CompareByParent)(const Row*, const Row*);
+typedef int (*Row_CompareByParent)(const Row*, const Row*, void*);
 
-int Row_compare(const void* v1, const void* v2);
+int Row_compare(const void* v1, const void* v2, void* context);
 
 typedef struct RowClass_ {
    const ObjectClass super;
@@ -102,7 +102,7 @@ typedef struct RowClass_ {
 #define Row_isVisible(r_, t_)  (As_Row(r_)->isVisible ? (As_Row(r_)->isVisible(r_, t_)) : true)
 #define Row_matchesFilter(r_, t_)  (As_Row(r_)->matchesFilter ? (As_Row(r_)->matchesFilter(r_, t_)) : false)
 #define Row_sortKeyString(r_)  (As_Row(r_)->sortKeyString ? (As_Row(r_)->sortKeyString(r_)) : "")
-#define Row_compareByParent(r1_, r2_)  (As_Row(r1_)->compareByParent ? (As_Row(r1_)->compareByParent(r1_, r2_)) : Row_compareByParent_Base(r1_, r2_))
+#define Row_compareByParent(r1_, r2_, ctx_)  (As_Row(r1_)->compareByParent ? (As_Row(r1_)->compareByParent(r1_, r2_, ctx_)) : Row_compareByParent_Base(r1_, r2_, ctx_))
 
 #define ONE_K 1024UL
 #define ONE_M (ONE_K * ONE_K)
@@ -162,7 +162,8 @@ void Row_printRate(RichString* str, double rate, bool coloring);
 
 int Row_printPercentage(float val, char* buffer, size_t n, uint8_t width, int* attr);
 
-static inline int Row_idEqualCompare(const void* v1, const void* v2) {
+static inline int Row_idEqualCompare(const void* v1, const void* v2, void* context) {
+   (void)context;
    const int p1 = ((const Row*)v1)->id;
    const int p2 = ((const Row*)v2)->id;
    return p1 != p2; /* return zero when equal */
@@ -177,6 +178,6 @@ static inline bool Row_isChildOf(const Row* this, int id) {
    return id == Row_getGroupOrParent(this);
 }
 
-int Row_compareByParent_Base(const void* v1, const void* v2);
+int Row_compareByParent_Base(const void* v1, const void* v2, void* context);
 
 #endif
diff --git a/Table.c b/Table.c
@@ -137,8 +137,8 @@ static void Table_buildTreeBranch(Table* this, int rowid, unsigned int level, in
    }
 }
 
-static int compareRowByKnownParentThenNatural(const void* v1, const void* v2) {
-   return Row_compareByParent((const Row*) v1, (const Row*) v2);
+static int compareRowByKnownParentThenNatural(const void* v1, const void* v2, void* context) {
+   return Row_compareByParent((const Row*) v1, (const Row*) v2, context);
 }
 
 // Builds a sorted tree from scratch, without relying on previously gathered information
@@ -168,7 +168,7 @@ static void Table_buildTree(Table* this) {
    }
 
    // Sort by known parent (roots first), then row ID
-   Vector_sort(this->rows, compareRowByKnownParentThenNatural);
+   Vector_sort(this->rows, compareRowByKnownParentThenNatural, this);
 
    // Find all processes whose parent is not visible
    for (int i = 0; i < vsize; i++) {
@@ -199,7 +199,7 @@ void Table_updateDisplayList(Table* this) {
          Table_buildTree(this);
    } else {
       if (this->needsSort)
-         Vector_sort(this->rows, NULL);
+         Vector_sort(this->rows, NULL, this);
       Vector_prune(this->displayList);
       int size = Vector_size(this->rows);
       for (int i = 0; i < size; i++)
diff --git a/Vector.c b/Vector.c
@@ -17,10 +17,9 @@ in the source distribution for its full text.
 #include "XUtils.h"
 
 
-typedef int(*CompareWithContext)(const void*, const void*, void*);
-
 typedef struct VectorSortContext_ {
    Object_Compare compare;
+   void* compareContext;
 } VectorSortContext;
 
 Vector* Vector_new(const ObjectClass* type, bool owner, int size) {
@@ -141,7 +140,7 @@ static void rotate(void* buffer, size_t leftSize, size_t rightSize) {
 }
 
 ATTR_NONNULL_N(1, 5)
-static void mergeRuns(void* array, size_t leftLen, size_t rightLen, size_t size, CompareWithContext compare, void* context) {
+static void mergeRuns(void* array, size_t leftLen, size_t rightLen, size_t size, Object_Compare compare, void* context) {
    assert(size > 0);
    if (leftLen == 0 || rightLen == 0 || size == 0)
       return;
@@ -182,7 +181,7 @@ static void mergeRuns(void* array, size_t leftLen, size_t rightLen, size_t size,
 }
 
 ATTR_NONNULL_N(1, 5)
-static size_t mergeSortSubarray(void* array, size_t unsortedLen, size_t limit, size_t size, CompareWithContext compare, void* context) {
+static size_t mergeSortSubarray(void* array, size_t unsortedLen, size_t limit, size_t size, Object_Compare compare, void* context) {
    assert(size > 0);
    if (size == 0)
       return 0;
@@ -248,13 +247,14 @@ ATTR_NONNULL
 static int Vector_sortCompare(const void* p1, const void* p2, void* context) {
    VectorSortContext* vc = (VectorSortContext*) context;
 
-   return vc->compare(*(const void* const*)p1, *(const void* const*)p2);
+   return vc->compare(*(const void* const*)p1, *(const void* const*)p2, vc->compareContext);
 }
 
 ATTR_NONNULL_N(1)
-void Vector_sort(Vector* this, Object_Compare compare) {
+void Vector_sort(Vector* this, Object_Compare compare, void* context) {
    VectorSortContext vc = {
       .compare = compare ? compare : this->type->compare,
+      .compareContext = context ? context : this,
    };
    assert(vc.compare);
    assert(Vector_isConsistent(this));
@@ -440,7 +440,7 @@ int Vector_indexOf(const Vector* this, const void* search_, Object_Compare compa
    for (int i = 0; i < this->items; i++) {
       const Object* o = this->array[i];
       assert(o);
-      if (compare(search, o) == 0) {
+      if (compare(search, o, NULL) == 0) {
          return i;
       }
    }
diff --git a/Vector.h b/Vector.h
@@ -35,7 +35,7 @@ void Vector_delete(Vector* this);
 
 void Vector_prune(Vector* this);
 
-void Vector_sort(Vector* this, Object_Compare compare);
+void Vector_sort(Vector* this, Object_Compare compare, void* context);
 
 void Vector_insert(Vector* this, int idx, void* data_);
 
diff --git a/pcp/Instance.c b/pcp/Instance.c
@@ -138,7 +138,8 @@ static int Instance_compareByKey(const Row* v1, const Row* v2, int key) {
    return 0;
 }
 
-static int Instance_compare(const void* v1, const void* v2) {
+static int Instance_compare(const void* v1, const void* v2, void* context) {
+   (void)context;
    const Instance* i1 = (const Instance*)v1;
    const Instance* i2 = (const Instance*)v2;
    const ScreenSettings* ss = i1->super.host->settings->ss;

Original file line number	Diff line number	Diff line change
`@@ -52,8 +52,8 @@ static void EnvScreen_scan(InfoScreen* this) {`
`52`	`52`	`InfoScreen_addLine(this, "Could not read process environment.");`
`53`	`53`	`}`
`54`	`54`
`55`		`- Vector_sort(this->lines, NULL);`
`56`		`- Vector_sort(panel->items, NULL);`
	`55`	`+ Vector_sort(this->lines, NULL, this);`
	`56`	`+ Vector_sort(panel->items, NULL, this);`
`57`	`57`	`Panel_setSelected(panel, idx);`
`58`	`58`	`}`
`59`	`59`
Original file line number	Diff line number	Diff line change
`@@ -59,7 +59,8 @@ void ListItem_append(ListItem* this, const char* text) {`
`59`	`59`	`this->value[newLen] = '\0';`
`60`	`60`	`}`
`61`	`61`
`62`		`-int ListItem_compare(const void* cast1, const void* cast2) {`
	`62`	`+int ListItem_compare(const void* cast1, const void* cast2, void* context) {`
	`63`	`+ (void)context;`
`63`	`64`	`const ListItem* obj1 = (const ListItem*) cast1;`
`64`	`65`	`const ListItem* obj2 = (const ListItem*) cast2;`
`65`	`66`	`return strcmp(obj1->value, obj2->value);`
Original file line number	Diff line number	Diff line change
`@@ -300,8 +300,8 @@ static void OpenFilesScreen_scan(InfoScreen* super) {`
`300`	`300`	`OpenFiles_Data_clear(&pdata->data);`
`301`	`301`	`}`
`302`	`302`	`free(pdata);`
`303`		`- Vector_sort(super->lines, NULL);`
`304`		`- Vector_sort(panel->items, NULL);`
	`303`	`+ Vector_sort(super->lines, NULL, super);`
	`304`	`+ Vector_sort(panel->items, NULL, super);`
`305`	`305`	`Panel_setSelected(panel, idx);`
`306`	`306`	`}`
`307`	`307`
Original file line number	Diff line number	Diff line change
`@@ -91,8 +91,8 @@ static void ProcessLocksScreen_scan(InfoScreen* this) {`
`91`	`91`	`}`
`92`	`92`	`}`
`93`	`93`	`free(pdata);`
`94`		`- Vector_sort(this->lines, NULL);`
`95`		`- Vector_sort(panel->items, NULL);`
	`94`	`+ Vector_sort(this->lines, NULL, this);`
	`95`	`+ Vector_sort(panel->items, NULL, this);`
`96`	`96`	`Panel_setSelected(panel, idx);`
`97`	`97`	`}`
`98`	`98`