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Commit 15960454 by Patrick Steinhardt
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examples: general: extract functions demonstrating object parsing

parent 8b93ccdf
Showing with 194 additions and 131 deletions
examples/general.c
......@@ -43,6 +43,10 @@
#include <stdio.h>
#include <string.h>
static void commit_parsing(git_repository *repo);
static void tag_parsing(git_repository *repo);
static void tree_parsing(git_repository *repo);
static void blob_parsing(git_repository *repo);
static void revwalking(git_repository *repo);
static void index_walking(git_repository *repo);
static void reference_listing(git_repository *repo);
......@@ -171,63 +175,6 @@ int main (int argc, char** argv)
git_oid_fmt(out, &oid);
printf("Written Object: %s\n", out);
// ### Object Parsing
// libgit2 has methods to parse every object type in Git so you don't have
// to work directly with the raw data. This is much faster and simpler
// than trying to deal with the raw data yourself.
// #### Commit Parsing
// [Parsing commit objects][pco] is simple and gives you access to all the
// data in the commit - the author (name, email, datetime), committer
// (same), tree, message, encoding and parent(s).
//
// [pco]: http://libgit2.github.com/libgit2/#HEAD/group/commit
printf("\n*Commit Parsing*\n");
git_commit *commit;
git_oid_fromstr(&oid, "8496071c1b46c854b31185ea97743be6a8774479");
error = git_commit_lookup(&commit, repo, &oid);
check_error(error, "looking up commit");
const git_signature *author, *cmtter;
const char *message;
time_t ctime;
unsigned int parents, p;
// Each of the properties of the commit object are accessible via methods,
// including commonly needed variations, such as `git_commit_time` which
// returns the author time and `git_commit_message` which gives you the
// commit message (as a NUL-terminated string).
message = git_commit_message(commit);
author = git_commit_author(commit);
cmtter = git_commit_committer(commit);
ctime = git_commit_time(commit);
// The author and committer methods return [git_signature] structures,
// which give you name, email and `when`, which is a `git_time` structure,
// giving you a timestamp and timezone offset.
printf("Author: %s (%s)\n", author->name, author->email);
// Commits can have zero or more parents. The first (root) commit will
// have no parents, most commits will have one (i.e. the commit it was
// based on) and merge commits will have two or more. Commits can
// technically have any number, though it's rare to have more than two.
parents = git_commit_parentcount(commit);
for (p = 0;p < parents;p++) {
git_commit *parent;
git_commit_parent(&parent, commit, p);
git_oid_fmt(out, git_commit_id(parent));
printf("Parent: %s\n", out);
git_commit_free(parent);
}
// Don't forget to close the object to prevent memory leaks. You will have
// to do this for all the objects you open and parse.
git_commit_free(commit);
// #### Writing Commits
......@@ -242,6 +189,7 @@ int main (int argc, char** argv)
git_oid tree_id, parent_id, commit_id;
git_tree *tree;
git_commit *parent;
const git_signature *author, *cmtter;
// Creating signatures for an authoring identity and time is simple. You
// will need to do this to specify who created a commit and when. Default
......@@ -279,110 +227,225 @@ int main (int argc, char** argv)
git_oid_fmt(out, &commit_id);
printf("New Commit: %s\n", out);
// #### Tag Parsing
commit_parsing(repo);
tag_parsing(repo);
tree_parsing(repo);
blob_parsing(repo);
revwalking(repo);
index_walking(repo);
reference_listing(repo);
config_files(repo_path);
// You can parse and create tags with the [tag management API][tm], which
// functions very similarly to the commit lookup, parsing and creation
// methods, since the objects themselves are very similar.
//
// [tm]: http://libgit2.github.com/libgit2/#HEAD/group/tag
printf("\n*Tag Parsing*\n");
// Finally, when you're done with the repository, you can free it as well.
git_repository_free(repo);
return 0;
}
/**
* ### Object Parsing
*
* libgit2 has methods to parse every object type in Git so you don't have
* to work directly with the raw data. This is much faster and simpler
* than trying to deal with the raw data yourself.
*/
/**
* #### Commit Parsing
*
* [Parsing commit objects][pco] is simple and gives you access to all the
* data in the commit - the author (name, email, datetime), committer
* (same), tree, message, encoding and parent(s).
*
* [pco]: http://libgit2.github.com/libgit2/#HEAD/group/commit
*/
static void commit_parsing(git_repository *repo)
{
const git_signature *author, *cmtter;
git_commit *commit, *parent;
git_oid oid;
char oid_hex[GIT_OID_HEXSZ+1];
const char *message;
unsigned int parents, p;
int error;
time_t ctime;
printf("\n*Commit Parsing*\n");
git_oid_fromstr(&oid, "8496071c1b46c854b31185ea97743be6a8774479");
error = git_commit_lookup(&commit, repo, &oid);
check_error(error, "looking up commit");
/**
* Each of the properties of the commit object are accessible via methods,
* including commonly needed variations, such as `git_commit_time` which
* returns the author time and `git_commit_message` which gives you the
* commit message (as a NUL-terminated string).
*/
message = git_commit_message(commit);
author = git_commit_author(commit);
cmtter = git_commit_committer(commit);
ctime = git_commit_time(commit);
/**
* The author and committer methods return [git_signature] structures,
* which give you name, email and `when`, which is a `git_time` structure,
* giving you a timestamp and timezone offset.
*/
printf("Author: %s (%s)\n", author->name, author->email);
/**
* Commits can have zero or more parents. The first (root) commit will
* have no parents, most commits will have one (i.e. the commit it was
* based on) and merge commits will have two or more. Commits can
* technically have any number, though it's rare to have more than two.
*/
parents = git_commit_parentcount(commit);
for (p = 0;p < parents;p++) {
memset(oid_hex, 0, sizeof(oid_hex));
git_commit_parent(&parent, commit, p);
git_oid_fmt(oid_hex, git_commit_id(parent));
printf("Parent: %s\n", oid_hex);
git_commit_free(parent);
}
git_commit_free(commit);
}
/**
* #### Tag Parsing
*
* You can parse and create tags with the [tag management API][tm], which
* functions very similarly to the commit lookup, parsing and creation
* methods, since the objects themselves are very similar.
*
* [tm]: http://libgit2.github.com/libgit2/#HEAD/group/tag
*/
static void tag_parsing(git_repository *repo)
{
git_commit *commit;
git_otype type;
git_tag *tag;
const char *tmessage, *tname;
git_otype ttype;
git_oid oid;
const char *name, *message;
int error;
printf("\n*Tag Parsing*\n");
// We create an oid for the tag object if we know the SHA and look it up
// the same way that we would a commit (or any other object).
/**
* We create an oid for the tag object if we know the SHA and look it up
* the same way that we would a commit (or any other object).
*/
git_oid_fromstr(&oid, "b25fa35b38051e4ae45d4222e795f9df2e43f1d1");
error = git_tag_lookup(&tag, repo, &oid);
check_error(error, "looking up tag");
// Now that we have the tag object, we can extract the information it
// generally contains: the target (usually a commit object), the type of
// the target object (usually 'commit'), the name ('v1.0'), the tagger (a
// git_signature - name, email, timestamp), and the tag message.
/**
* Now that we have the tag object, we can extract the information it
* generally contains: the target (usually a commit object), the type of
* the target object (usually 'commit'), the name ('v1.0'), the tagger (a
* git_signature - name, email, timestamp), and the tag message.
*/
git_tag_target((git_object **)&commit, tag);
tname = git_tag_name(tag); // "test"
ttype = git_tag_target_type(tag); // GIT_OBJ_COMMIT (otype enum)
tmessage = git_tag_message(tag); // "tag message\n"
printf("Tag Message: %s\n", tmessage);
name = git_tag_name(tag); /* "test" */
type = git_tag_target_type(tag); /* GIT_OBJ_COMMIT (otype enum) */
message = git_tag_message(tag); /* "tag message\n" */
printf("Tag Message: %s\n", message);
git_commit_free(commit);
}
// #### Tree Parsing
/**
* #### Tree Parsing
*
* [Tree parsing][tp] is a bit different than the other objects, in that
* we have a subtype which is the tree entry. This is not an actual
* object type in Git, but a useful structure for parsing and traversing
* tree entries.
*
* [tp]: http://libgit2.github.com/libgit2/#HEAD/group/tree
*/
static void tree_parsing(git_repository *repo)
{
const git_tree_entry *entry;
size_t cnt;
git_object *obj;
git_tree *tree;
git_oid oid;
// [Tree parsing][tp] is a bit different than the other objects, in that
// we have a subtype which is the tree entry. This is not an actual
// object type in Git, but a useful structure for parsing and traversing
// tree entries.
//
// [tp]: http://libgit2.github.com/libgit2/#HEAD/group/tree
printf("\n*Tree Parsing*\n");
const git_tree_entry *entry;
git_object *objt;
// Create the oid and lookup the tree object just like the other objects.
git_oid_fromstr(&oid, "2a741c18ac5ff082a7caaec6e74db3075a1906b5");
/**
* Create the oid and lookup the tree object just like the other objects.
*/
git_oid_fromstr(&oid, "f60079018b664e4e79329a7ef9559c8d9e0378d1");
git_tree_lookup(&tree, repo, &oid);
// Getting the count of entries in the tree so you can iterate over them
// if you want to.
size_t cnt = git_tree_entrycount(tree); // 3
printf("tree entries: %d\n", (int)cnt);
/**
* Getting the count of entries in the tree so you can iterate over them
* if you want to.
*/
cnt = git_tree_entrycount(tree); /* 2 */
printf("tree entries: %d\n", (int) cnt);
entry = git_tree_entry_byindex(tree, 0);
printf("Entry name: %s\n", git_tree_entry_name(entry)); // "hello.c"
printf("Entry name: %s\n", git_tree_entry_name(entry)); /* "README" */
// You can also access tree entries by name if you know the name of the
// entry you're looking for.
/**
* You can also access tree entries by name if you know the name of the
* entry you're looking for.
*/
entry = git_tree_entry_byname(tree, "README");
git_tree_entry_name(entry); // "hello.c"
// Once you have the entry object, you can access the content or subtree
// (or commit, in the case of submodules) that it points to. You can also
// get the mode if you want.
git_tree_entry_to_object(&objt, repo, entry); // blob
git_tree_entry_name(entry); /* "README" */
// Remember to close the looked-up object once you are done using it
git_object_free(objt);
/**
* Once you have the entry object, you can access the content or subtree
* (or commit, in the case of submodules) that it points to. You can also
* get the mode if you want.
*/
git_tree_entry_to_object(&obj, repo, entry); /* blob */
// #### Blob Parsing
/**
* Remember to close the looked-up object once you are done using it
*/
git_object_free(obj);
}
// The last object type is the simplest and requires the least parsing
// help. Blobs are just file contents and can contain anything, there is
// no structure to it. The main advantage to using the [simple blob
// api][ba] is that when you're creating blobs you don't have to calculate
// the size of the content. There is also a helper for reading a file
// from disk and writing it to the db and getting the oid back so you
// don't have to do all those steps yourself.
//
// [ba]: http://libgit2.github.com/libgit2/#HEAD/group/blob
/**
* #### Blob Parsing
*
* The last object type is the simplest and requires the least parsing
* help. Blobs are just file contents and can contain anything, there is
* no structure to it. The main advantage to using the [simple blob
* api][ba] is that when you're creating blobs you don't have to calculate
* the size of the content. There is also a helper for reading a file
* from disk and writing it to the db and getting the oid back so you
* don't have to do all those steps yourself.
*
* [ba]: http://libgit2.github.com/libgit2/#HEAD/group/blob
*/
static void blob_parsing(git_repository *repo)
{
git_blob *blob;
git_oid oid;
printf("\n*Blob Parsing*\n");
git_blob *blob;
git_oid_fromstr(&oid, "1385f264afb75a56a5bec74243be9b367ba4ca08");
git_blob_lookup(&blob, repo, &oid);
// You can access a buffer with the raw contents of the blob directly.
// Note that this buffer may not be contain ASCII data for certain blobs
// (e.g. binary files): do not consider the buffer a NULL-terminated
// string, and use the `git_blob_rawsize` attribute to find out its exact
// size in bytes
printf("Blob Size: %ld\n", (long)git_blob_rawsize(blob)); // 8
git_blob_rawcontent(blob); // "content"
revwalking(repo);
index_walking(repo);
reference_listing(repo);
config_files(repo_path);
// Finally, when you're done with the repository, you can free it as well.
git_repository_free(repo);
return 0;
/**
* You can access a buffer with the raw contents of the blob directly.
* Note that this buffer may not be contain ASCII data for certain blobs
* (e.g. binary files): do not consider the buffer a NULL-terminated
* string, and use the `git_blob_rawsize` attribute to find out its exact
* size in bytes
* */
printf("Blob Size: %ld\n", (long)git_blob_rawsize(blob)); /* 8 */
git_blob_rawcontent(blob); /* "content" */
}
/**
......
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