settings: allow swapping out memory allocator

Tie in the newly created infrastructure for swapping out memory
allocators into our settings code. A user can now simply use the new
option "GIT_OPT_SET_ALLOCATOR" with `git_libgit2_opts`, passing in an
already initialized allocator structure as vararg.

2 files changed, 31 insertions, 0 deletions

diff --git a/include/git2/common.h b/include/git2/common.h
index f65cfdd01..f095e5990 100644
--- a/include/git2/common.h
+++ b/include/git2/common.h
@@ -183,6 +183,7 @@ typedef enum {
 	GIT_OPT_GET_WINDOWS_SHAREMODE,
 	GIT_OPT_SET_WINDOWS_SHAREMODE,
 	GIT_OPT_ENABLE_STRICT_HASH_VERIFICATION,
+	GIT_OPT_SET_ALLOCATOR
 } git_libgit2_opt_t;
 
 /**
@@ -345,6 +346,12 @@ typedef enum {
  *		> additional checksum calculation on each object. This defaults
  *		> to enabled.
  *
+ *	 opts(GIT_OPT_SET_ALLOCATOR, git_allocator *allocator)
+ *
+ *		> Set the memory allocator to a different memory allocator. This
+ *		> allocator will then be used to make all memory allocations for
+ *		> libgit2 operations.
+ *
  * @param option Option key
  * @param ... value to set the option
  * @return 0 on success, <0 on failure
diff --git a/include/git2/sys/alloc.h b/include/git2/sys/alloc.h
index a0955ce8b..4bc5323e2 100644
--- a/include/git2/sys/alloc.h
+++ b/include/git2/sys/alloc.h
@@ -72,6 +72,30 @@ typedef struct {
 	void (*gfree)(void *ptr);
 } git_allocator;
 
+/**
+ * Initialize the allocator structure to use the `stdalloc` pointer.
+ *
+ * Set up the structure so that all of its members are using the standard
+ * "stdalloc" allocator functions. The structure can then be used with
+ * `git_allocator_setup`.
+ *
+ * @param allocator The allocator that is to be initialized.
+ * @return An error code or 0.
+ */
+int git_stdalloc_init_allocator(git_allocator *allocator);
+
+/**
+ * Initialize the allocator structure to use the `crtdbg` pointer.
+ *
+ * Set up the structure so that all of its members are using the "crtdbg"
+ * allocator functions. Note that this allocator is only available on Windows
+ * platforms and only if libgit2 is being compiled with "-DMSVC_CRTDBG".
+ *
+ * @param allocator The allocator that is to be initialized.
+ * @return An error code or 0.
+ */
+int git_win32_crtdbg_init_allocator(git_allocator *allocator);
+
 GIT_END_DECL
 
 #endif