Updated ODB API

Author: p-ranav

README.md

@@ -971,9 +971,9 @@ The project is available under the [MIT](https://opensource.org/licenses/MIT) li
 
 | libgit2 | cppgit2:: |
 | --- | --- |
-| `git_odb_add_alternate` | |
-| `git_odb_add_backend` | |
-| `git_odb_add_disk_alternate` | |
+| `git_odb_add_alternate` | `odb::add_alternate_backend` |
+| `git_odb_add_backend` | `odb::add_backend` |
+| `git_odb_add_disk_alternate` | `odb::add_disk_alternate_backend` |
 | `git_odb_backend_loose` | `odb::create_backend_for_loose_objects` |
 | `git_odb_backend_one_pack` | `odb::create_backend_for_one_packfile` |
 | `git_odb_backend_pack` | `odb::create_backend_for_packfiles` |
@@ -1004,8 +1004,8 @@ The project is available under the [MIT](https://opensource.org/licenses/MIT) li
 | `git_odb_stream_free` | `odb::stream::~stream` |
 | `git_odb_stream_read` | `odb::stream::read` |
 | `git_odb_stream_write` | `odb::stream::write` |
-| `git_odb_write` | |
-| `git_odb_write_pack` | |
+| `git_odb_write` | `odb::write` |
+| `git_odb_write_pack` | **Not Implemented** |
 
 
 ### oid

include/cppgit2/odb.hpp

@@ -6,9 +6,9 @@
 #include <cppgit2/oid.hpp>
 #include <cppgit2/ownership.hpp>
 #include <git2.h>
+#include <tuple>
 #include <utility>
 #include <vector>
-#include <tuple>
 
 namespace cppgit2 {
 
@@ -40,6 +40,25 @@ class odb : public libgit2_api {
     git_odb_backend *c_ptr_;
   };
 
+  // Add a custom backend to an existing Object DB; this backend will work as an
+  // alternate.
+  //
+  // Alternate backends are always checked for objects after all the main
+  // backends have been exhausted. The backends are checked in relative
+  // ordering, based on the value of the priority parameter. Writing is disabled
+  // on alternate backends.
+  void add_alternate_backend(const backend &backend, int priority);
+
+  // Add a custom backend to an existing Object DB
+  // The backends are checked in relative ordering, based on the value of the priority parameter.
+  void add_backend(const backend &backend, int priority);
+
+  // Add an on-disk alternate to an existing Object DB.
+  // Note that the added path must point to an objects, not to a full repository, to use it as an alternate store.
+  // Alternate backends are always checked for objects after all the main backends have been exhausted.
+  // Writing is disabled on alternate backends.
+  void add_disk_alternate_backend(const std::string &path);
+
   // Create a backend for loose objects
   static backend
   create_backend_for_loose_objects(const std::string &objects_dir,
@@ -298,15 +317,19 @@ class odb : public libgit2_api {
   // all backends.
   //
   // Returns {stream, length of object, type of object}
-  std::tuple<stream, size_t, cppgit2::object::object_type> open_rstream(const oid &id);
+  std::tuple<stream, size_t, cppgit2::object::object_type>
+  open_rstream(const oid &id);
 
   // Open a stream to write an object into the ODB
   // The type and final length of the object must be specified when opening the
   // stream. The returned stream will be of type GIT_STREAM_WRONLY, and it won't
   // be effective until git_odb_stream_finalize_write is called and returns
   // without an error
   stream open_wstream(cppgit2::object::object_size size,
-                             cppgit2::object::object_type type);
+                      cppgit2::object::object_type type);
+
+  // Write an object directly into the ODB
+  oid write(const void *data, size_t length, cppgit2::object::object_type type);
 
   // Access libgit2 C ptr
   const git_odb *c_ptr() const;

src/odb.cpp

@@ -12,6 +12,21 @@ odb::~odb() {
     git_odb_free(c_ptr_);
 }
 
+void odb::add_alternate_backend(const backend &backend, int priority) {
+  if (git_odb_add_alternate(c_ptr_, backend.c_ptr_, priority))
+    throw git_exception();
+}
+
+void odb::add_backend(const backend &backend, int priority) {
+  if (git_odb_add_backend(c_ptr_, backend.c_ptr_, priority))
+    throw git_exception();
+}
+
+void odb::add_disk_alternate_backend(const std::string &path) {
+  if (git_odb_add_disk_alternate(c_ptr_, path.c_str()))
+    throw git_exception();
+}
+
 odb::backend
 odb::create_backend_for_loose_objects(const std::string &objects_dir,
                                       int compression_level, bool do_fsync,
@@ -141,7 +156,8 @@ odb odb::open(const std::string &objects_dir) {
   return result;
 }
 
-std::tuple<odb::stream, size_t, cppgit2::object::object_type> odb::open_rstream(const oid &id) {
+std::tuple<odb::stream, size_t, cppgit2::object::object_type>
+odb::open_rstream(const oid &id) {
   stream result(nullptr);
   size_t length;
   git_object_t type;
@@ -151,10 +167,20 @@ std::tuple<odb::stream, size_t, cppgit2::object::object_type> odb::open_rstream(
 }
 
 odb::stream odb::open_wstream(cppgit2::object::object_size size,
-                            cppgit2::object::object_type type) {
+                              cppgit2::object::object_type type) {
   stream result(nullptr);
-  if (git_odb_open_wstream(&result.c_ptr_, c_ptr_, static_cast<git_object_size_t>(size), 
-    static_cast<git_object_t>(type)))
+  if (git_odb_open_wstream(&result.c_ptr_, c_ptr_,
+                           static_cast<git_object_size_t>(size),
+                           static_cast<git_object_t>(type)))
+    throw git_exception();
+  return result;
+}
+
+oid odb::write(const void *data, size_t length,
+               cppgit2::object::object_type type) {
+  oid result;
+  if (git_odb_write(result.c_ptr(), c_ptr_, data, length,
+                    static_cast<git_object_t>(type)))
     throw git_exception();
   return result;
 }