feat(heap): thread-safety features

Makefile

@@ -8,6 +8,8 @@ SRC_DIR ?= src
 TEST_DIR ?= test
 INC_DIRS ?= include
 
+LIB := $(BUILD_DIR)/$(LIB_FILENAME)
+
 SRCS != find '$(SRC_DIR)' -iname '*.c'
 SRCS_H != find $(INC_DIRS) -iname '*.h'
 SRCS_TEST != find '$(TEST_DIR)' -iname '*.c'
@@ -40,7 +42,7 @@ all: vieter
 objs: $(OBJS)
 
 .PHONY: vieter
-vieter: $(BUILD_DIR)/$(LIB_FILENAME)
+vieter: $(LIB)
 $(BUILD_DIR)/$(LIB_FILENAME): $(OBJS)
 	ar -rcs $@ $(OBJS)
 
@@ -69,10 +71,11 @@ build-test: $(BINS_TEST)
 
 # For simplicity, we link every object file to each of the test files. This
 # might be changed later if this starts to become too slow.
-$(BINS_TEST): %: %.c.o $(OBJS)
-	$(CC) $^ -o $@
+$(BINS_TEST): %: %.c.o $(LIB)
+	$(CC) \
+		$^ -o $@
 
-# Allow with the include directory, each test includes $(TEST_DIR) (which
+# Along with the include directory, each test includes $(TEST_DIR) (which
 # contains the acutest.h header file), and the src directory of the module it's
 # testing. This allows tests to access internal methods, which aren't publicly
 # exposed.

README.md

@@ -6,7 +6,7 @@ be implemented in C (or just parts I want to implement in C because it's fun).
 The goal of this library is to be as self-contained as possible; data
 structures should be implemented manually if possible.
 
-See the [source code](/src) for the list of modules.
+See the [source code](src) for the list of modules.
 
 ## Development
 
@@ -43,7 +43,7 @@ only used in a .c file, the import should be placed in the .c file instead.
 
 This library uses [Acutest](https://github.com/mity/acutest) for its tests.
 Tests should be placed in the `test` subdirectory, further divided into
-directories that correspond those in `src`. Test files should begin with
+directories that correspond to those in `src`. Test files should begin with
 `test_`, and their format should follow the expected format for Acutest.
 
 Each `test_` is compiled separately into a binary, linked with libvieter. A

include/vieter_cron.h

@@ -37,7 +37,7 @@ typedef struct vieter_cron_simple_time {
 /*
  * Allocate and initialize a new empty cron expression.
  */
-vieter_cron_expression *ce_init();
+vieter_cron_expression *vieter_cron_expr_init();
 
 /*
  * Deallocate a cron expression.

include/vieter_heap.h

@@ -11,7 +11,7 @@ typedef enum vieter_heap_error {
 } vieter_heap_error;
 
 /*
- * Allocate and initalize an empty heap.
+ * Allocate and initialize an empty heap.
  */
 vieter_heap *vieter_heap_init();
 
@@ -41,4 +41,22 @@ vieter_heap_error vieter_heap_pop(void **out, vieter_heap *heap);
  */
 vieter_heap_error vieter_heap_peek(void **out, vieter_heap *heap);
 
+/*
+ * Acquire a read lock on the heap. Return value is the result of
+ * pthread_rwlock_rdlock.
+ */
+int vieter_heap_rlock(vieter_heap *heap);
+
+/*
+ * Acquire a write lock on the heap. Return value is the result of
+ * pthread_rwlock_wrlock.
+ */
+int vieter_heap_wlock(vieter_heap *heap);
+
+/*
+ * Unlock the lock after having acquired it. Return value is the result of
+ * pthread_rwlock_unlock.
+ */
+int vieter_heap_unlock(vieter_heap *heap);
+
 #endif

src/heap/vieter_heap.c

@@ -2,7 +2,13 @@
 
 #include <stdlib.h>
 
-vieter_heap *vieter_heap_init() { return calloc(1, sizeof(vieter_heap)); }
+vieter_heap *vieter_heap_init() {
+  vieter_heap *heap = calloc(1, sizeof(vieter_heap));
+
+  pthread_rwlock_init(&heap->lock, NULL);
+
+  return heap;
+}
 
 uint64_t vieter_heap_size(vieter_heap *heap) {
   uint64_t size = 0;
@@ -76,3 +82,15 @@ vieter_heap_error vieter_heap_peek(void **out, vieter_heap *heap) {
 
   return vieter_heap_ok;
 }
+
+int vieter_heap_rlock(vieter_heap *heap) {
+  return pthread_rwlock_rdlock(&heap->lock);
+}
+
+int vieter_heap_wlock(vieter_heap *heap) {
+  return pthread_rwlock_wrlock(&heap->lock);
+}
+
+int vieter_heap_unlock(vieter_heap *heap) {
+  return pthread_rwlock_unlock(&heap->lock);
+}

src/heap/vieter_heap_internal.h

@@ -1,6 +1,8 @@
 #include "vieter_heap.h"
 #include "vieter_heap_tree.h"
+#include <pthread.h>
 
 struct vieter_heap {
   vieter_heap_node *tree;
+  pthread_rwlock_t lock;
 };

src/heap/vieter_heap_tree.h

@@ -18,7 +18,7 @@ typedef struct vieter_heap_node {
 } vieter_heap_node;
 
 /*
- * Allocate an initialize a heap node object.
+ * Allocate and initialize a heap node object.
  */
 vieter_heap_node *vieter_heap_node_init();