Add pull example

carlosmn · carlosmn · commit ed194ec8f30d · 2014-06-10T19:34:38.000+02:00
diff --git a/examples/pull.c b/examples/pull.c
@@ -0,0 +1,139 @@
+/*
+ * libgit2 "blame" example - shows how to use the blame API
+ *
+ * Written by the libgit2 contributors
+ *
+ * To the extent possible under law, the author(s) have dedicated all copyright
+ * and related and neighboring rights to this software to the public domain
+ * worldwide. This software is distributed without any warranty.
+ *
+ * You should have received a copy of the CC0 Public Domain Dedication along
+ * with this software. If not, see
+ * <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+#include <stdio.h>
+
+#include "common.h"
+
+/**
+ * This example implements the safe portion of the git's 'pull'
+ * command. That is, merging fro upstream, which is the behaviour
+ * which does not loose procedence information or reverse history.
+ */
+int main(int argc, char **argv)
+{
+	git_repository *repo;
+	git_reference *current_branch, *upstream;
+	git_buf remote_name = {0};
+	git_remote *remote;
+
+	git_threads_init();
+
+	/**
+	 * Figure out what the current branch's upstream remote is so
+	 * we know from which remote to fetch
+	 */
+	check_lg2(git_repository_open_ext(&repo, ".", 0, NULL), "failed to open repo", NULL);
+	check_lg2(git_repository_head(&current_branch, repo), "failed to lookup current branch", NULL);
+	check_lg2(git_branch_remote_name(&remote_name, repo, git_reference_name(current_branch)),
+		  "failed to get the reference's upstream", NULL);
+	check_lg2(git_remote_load(&remote, repo, remote_name.ptr), "failed to load remote", NULL);
+	git_buf_free(&remote_name);
+	check_lg2(git_remote_fetch(remote, NULL, NULL), "failed to fetch from upstream", NULL);
+
+	/**
+	 * Now that we have the updated data from the remote, look up
+	 * our branch's upstream and merge from it.
+	 */
+	{
+		git_merge_head *merge_heads[1];
+	
+		check_lg2(git_branch_upstream(&upstream, current_branch), "failed to get upstream branch", NULL);
+		check_lg2(git_merge_head_from_ref(&merge_heads[0], repo, upstream), "failed to create merge head", NULL);
+		check_lg2(git_merge(repo, (const git_merge_head **) merge_heads, 1, NULL, NULL), "failed to merge", NULL);
+		git_merge_head_free(merge_heads[1]);
+	}
+
+	/**
+	 * Once the merge operation succeeds, we need to check whether
+	 * there were any conflicts merging
+	 */
+	{
+		git_index *index;
+		int has_conflicts;
+
+		check_lg2(git_repository_index(&index, repo), "failed to load index", NULL);
+		has_conflicts = git_index_has_conflicts(index);
+
+		git_index_free(index);
+
+		if (has_conflicts) {
+			printf("There were conflicts merging. Please resolve them and commit\n");
+			git_reference_free(upstream);
+			git_reference_free(current_branch);
+			git_repository_free(repo);
+
+			return 0;
+		}
+	}
+
+	/**
+	 * If there were no conflicts, then we commit with the message
+	 * that was prepared by the merge operation.
+	 *
+	 * A tool would take this opportunity to spawn the user's
+	 * editor and let them change it, but that is outside of our
+	 * purpose here.
+	 *
+	 * 
+	 */
+	{
+		git_index *index;
+		git_buf message = {0};
+		git_oid commit_id, tree_id;
+		git_commit *parents[2];
+		git_signature *user;
+		git_tree *tree;
+
+		/* Get the contents of the index into the repo as the tree want for the commit */
+		check_lg2(git_repository_index(&index, repo), "failed to load index", NULL);
+		check_lg2(git_index_write_tree(&tree_id, index), "failed to write tree", NULL);
+		git_index_free(index);
+
+		check_lg2(git_signature_default(&user, repo), "failed to get user's ident", NULL);
+		check_lg2(git_repository_message(&message, repo), "failed to get message", NULL);
+
+		check_lg2(git_tree_lookup(&tree, repo, &tree_id), "failed to lookup tree", NULL);
+
+		check_lg2(git_commit_lookup(&parents[0], repo, git_reference_target(current_branch)),
+			  "failed to lookup first parent", NULL);
+		check_lg2(git_commit_lookup(&parents[1], repo, git_reference_target(upstream)),
+			  "failed to lookup second parent", NULL);
+
+		check_lg2(git_commit_create(&commit_id, repo, "HEAD", user, user,
+					    NULL, message.ptr,
+					    tree, 2, (const git_commit **) parents),
+			  "failed to create commit", NULL);
+
+		git_tree_free(tree);
+		git_signature_free(user);
+	}
+	
+	git_reference_free(upstream);
+	git_reference_free(current_branch);
+	git_repository_free(repo);
+
+	return 0;
+
+}
+
+
+
+
+
+
+
+
+
+
