feat(tree): add bindings and api

lib/src/bindings/tree.dart

@@ -21,16 +21,57 @@ Pointer<git_tree> lookup(Pointer<git_repository> repo, Pointer<git_oid> id) {
   }
 }
 
-/// Lookup a tree object from the repository, given a prefix of its identifier (short id).
+/// Get the repository that contains the tree.
+Pointer<git_repository> owner(Pointer<git_tree> tree) =>
+    libgit2.git_tree_owner(tree);
+
+/// Lookup a tree entry by its position in the tree.
+///
+/// This returns a tree entry that is owned by the tree. You don't have to free it,
+/// but you must not use it after the tree is released.
+///
+/// Throws [RangeError] when provided index is outside of valid range.
+Pointer<git_tree_entry> getByIndex(Pointer<git_tree> tree, int index) {
+  final result = libgit2.git_tree_entry_byindex(tree, index);
+
+  if (result == nullptr) {
+    throw RangeError('Out of bounds');
+  } else {
+    return result;
+  }
+}
+
+/// Lookup a tree entry by its filename.
+///
+/// This returns a tree entry that is owned by the tree. You don't have to free it,
+/// but you must not use it after the tree is released.
+///
+/// Throws [ArgumentError] if nothing found for provided filename.
+Pointer<git_tree_entry> getByName(Pointer<git_tree> tree, String filename) {
+  final filenameC = filename.toNativeUtf8().cast<Int8>();
+  final result = libgit2.git_tree_entry_byname(tree, filenameC);
+
+  calloc.free(filenameC);
+
+  if (result == nullptr) {
+    throw ArgumentError.value('$filename was not found');
+  } else {
+    return result;
+  }
+}
+
+/// Retrieve a tree entry contained in a tree or in any of its subtrees, given its relative path.
+///
+/// Unlike the other lookup functions, the returned tree entry is owned by the user and must be
+/// freed explicitly with `entryFree()`.
 ///
 /// Throws a [LibGit2Error] if error occured.
-Pointer<git_tree> lookupPrefix(
-  Pointer<git_repository> repo,
-  Pointer<git_oid> id,
-  int len,
-) {
-  final out = calloc<Pointer<git_tree>>();
-  final error = libgit2.git_tree_lookup_prefix(out, repo, id, len);
+Pointer<git_tree_entry> getByPath(Pointer<git_tree> root, String path) {
+  final out = calloc<Pointer<git_tree_entry>>();
+  final pathC = path.toNativeUtf8().cast<Int8>();
+  final error = libgit2.git_tree_entry_bypath(out, root, pathC);
+
+  calloc.free(pathC);
 
   if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
@@ -39,5 +80,34 @@ Pointer<git_tree> lookupPrefix(
   }
 }
 
+/// Get the number of entries listed in a tree.
+int entryCount(Pointer<git_tree> tree) => libgit2.git_tree_entrycount(tree);
+
+/// Get the id of the object pointed by the entry.
+Pointer<git_oid> entryId(Pointer<git_tree_entry> entry) =>
+    libgit2.git_tree_entry_id(entry);
+
+/// Get the filename of a tree entry.
+String entryName(Pointer<git_tree_entry> entry) =>
+    libgit2.git_tree_entry_name(entry).cast<Utf8>().toDartString();
+
+/// Get the UNIX file attributes of a tree entry.
+int entryFilemode(Pointer<git_tree_entry> entry) =>
+    libgit2.git_tree_entry_filemode(entry);
+
+/// Compare two tree entries.
+///
+/// Returns <0 if e1 is before e2, 0 if e1 == e2, >0 if e1 is after e2.
+int compare(Pointer<git_tree_entry> e1, Pointer<git_tree_entry> e2) {
+  return libgit2.git_tree_entry_cmp(e1, e2);
+}
+
+/// Free a user-owned tree entry.
+///
+/// IMPORTANT: This function is only needed for tree entries owned by the user,
+/// such as `getByPath()`.
+void entryFree(Pointer<git_tree_entry> entry) =>
+    libgit2.git_tree_entry_free(entry);
+
 /// Close an open tree to release memory.
 void free(Pointer<git_tree> tree) => libgit2.git_tree_free(tree);