rework pr to not break existing code

src/dice/ffi/metall.cpp

@@ -22,22 +22,15 @@ metall_manager *open_impl(char const *path) {
     return reinterpret_cast<metall_manager *>(manager);
 }
 
-metall_manager *metall_open(char const *path) {
-    return open_impl<metall::open_only>(path);
-}
-
-metall_manager *metall_open_read_only(char const *path) {
-    return open_impl<metall::open_read_only>(path);
-}
-
-metall_manager *metall_create(char const *path, size_t capacity) {
+template<typename Create>
+metall_manager *create_impl(char const *path, Create &&create) {
     if (std::filesystem::exists(path)) {
         // prevent accidental overwrite
         errno = EEXIST;
         return nullptr;
     }
 
-    auto *manager = new metall_manager_t{metall::create_only, path, capacity};
+    auto *manager = std::invoke(create, path);
     if (!manager->check_sanity()) {
         delete manager;
         errno = ENOTRECOVERABLE;
@@ -47,6 +40,26 @@ metall_manager *metall_create(char const *path, size_t capacity) {
     return reinterpret_cast<metall_manager *>(manager);
 }
 
+metall_manager *metall_open(char const *path) {
+    return open_impl<metall::open_only>(path);
+}
+
+metall_manager *metall_open_read_only(char const *path) {
+    return open_impl<metall::open_read_only>(path);
+}
+
+metall_manager *metall_create(char const *path) {
+    return create_impl(path, [](char const *path) {
+        return new metall_manager_t{metall::create_only, path};
+    });
+}
+
+metall_manager *metall_create_with_capacity_limit(char const *path, size_t capacity) {
+    return create_impl(path, [capacity](char const *path) {
+        return new metall_manager_t{metall::create_only, path, capacity};
+    });
+}
+
 bool metall_is_read_only(metall_manager const *manager) {
     return reinterpret_cast<metall_manager_t const *>(manager)->read_only();
 }

src/dice/ffi/metall.h

@@ -3,7 +3,8 @@
 
 #include <stdbool.h>
 #include <stddef.h>
-#include <metall/defs.hpp>
+
+#include <metall/logger_interface.h>
 
 #if __has_include(<metall/logger_interface.h>)
 #include <metall/logger_interface.h>
@@ -53,12 +54,21 @@ metall_manager *metall_open_read_only(char const *path);
 /**
  * @brief Attempts to create a metall datastore at path
  * @param path path at which to create a datastore
- * @param capacity maximum capacity for metall manager, for default value use METALL_DEFAULT_CAPACITY
  * @return true on success, false on failure. On failure, sets errno to one of the following values:
  *      - EEXIST if the given path already exists
  *      - ENOTRECOVERABLE if the datastore could not be created for some other reason
  */
-metall_manager *metall_create(char const *path, size_t capacity);
+metall_manager *metall_create(char const *path);
+
+/**
+ * @brief Attempts to create a metall datastore at path
+ * @param path path at which to create a datastore
+ * @param capacity maximum capacity for metall manager
+ * @return true on success, false on failure. On failure, sets errno to one of the following values:
+ *      - EEXIST if the given path already exists
+ *      - ENOTRECOVERABLE if the datastore could not be created for some other reason
+ */
+metall_manager *metall_create_with_capacity_limit(char const *path, size_t capacity);
 
 /**
  * @brief Returns true if the metall manager was opened as read-only

tests/tests_Sanity.cpp

@@ -19,7 +19,7 @@ TEST_SUITE("metall-ffi") {
         std::string const snap_path = path + "-snap";
 
         {
-            metall_manager *manager = metall_create(path.c_str(), METALL_DEFAULT_CAPACITY);
+            metall_manager *manager = metall_create(path.c_str());
             if (manager == nullptr) {
                 FAIL("failed to create: ", strerror(errno));
             }
@@ -98,7 +98,7 @@ TEST_SUITE("metall-ffi") {
 
     TEST_CASE("prevent open same datastore twice") {
         std::string const path = "/tmp/" + std::to_string(std::random_device{}());
-        metall_manager *manager = metall_create(path.c_str(), METALL_DEFAULT_CAPACITY);
+        metall_manager *manager = metall_create(path.c_str());
         if (manager == nullptr) {
             FAIL("failed to create datastore: ", strerror(errno));
         }
@@ -114,4 +114,18 @@ TEST_SUITE("metall-ffi") {
         metall_close(manager);
         CHECK(metall_remove(path.c_str()));
     }
+
+    TEST_CASE("capacity limit") {
+        std::string const path = "/tmp/" + std::to_string(std::random_device{}());
+        metall_manager *manager = metall_create_with_capacity_limit(path.c_str(), 1);
+        if (manager == nullptr) {
+            FAIL("failed to create datastore: ", strerror(errno));
+        }
+
+        auto ret = metall_malloc(manager, "aaa", 1'000'000'000);
+        if (ret != nullptr) {
+            metall_free(manager, "aaa");
+            FAIL("Did not refuse to allocate");
+        }
+    }
 }