Feature: capacity param (#17)

conanfile.py

@@ -50,7 +50,7 @@ def _configure_cmake(self):
         if self._cmake:
             return self._cmake
         self._cmake = CMake(self)
-        self._cmake.configure(variables={"USE_CONAN": False})
+        self._cmake.configure()
 
         return self._cmake
 

src/dice/ffi/metall.cpp

@@ -1,6 +1,8 @@
 #include <dice/ffi/metall.h>
 #include <dice/ffi/metall_internal.hpp>
 
+#include <functional>
+
 using metall_manager_t = dice::metall_ffi::internal::metall_manager;
 
 template<auto open_mode>
@@ -22,22 +24,15 @@ 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) {
+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};
+    auto *manager = std::invoke(std::forward<Create>(create), path);
     if (!manager->check_sanity()) {
         delete manager;
         errno = ENOTRECOVERABLE;
@@ -47,6 +42,26 @@ metall_manager *metall_create(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) {
+    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

@@ -30,6 +30,7 @@ typedef enum metall_log_level {
 } metall_log_level;
 #endif
 
+
 typedef struct metall_manager metall_manager;
 
 /**
@@ -57,6 +58,16 @@ metall_manager *metall_open_read_only(char const *path);
  */
 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
  * @param manager manager to check

tests/tests_Sanity.cpp

@@ -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");
+        }
+    }
 }