add examples for docs

3 files changed, 463 insertions, 0 deletions

diff --git a/api.docurium b/api.docurium
index 6aa5dcaf1..9e17817db 100644
--- a/api.docurium
+++ b/api.docurium
@@ -4,6 +4,8 @@
  "input":  "include/git2",
  "prefix": "git_",
  "output": "docs",
+ "branch": "gh-pages",
+ "examples": "examples",
  "legacy":  {
     "input": {"src/git": ["v0.1.0"],
               "src/git2": ["v0.2.0", "v0.3.0"]}
diff --git a/examples/libgit.c b/examples/libgit.c
new file mode 100644
index 000000000..66df2687f
--- /dev/null
+++ b/examples/libgit.c
@@ -0,0 +1,418 @@
+// [**libgit2**][lg] is a portable, pure C implementation of the Git core methods
+// provided as a re-entrant linkable library with a solid API, allowing you
+// to write native speed custom Git applications in any language which 
+// supports C bindings. 
+//
+// [This file][ex] is an example of using that API in a real, compilable C file.
+// Before published, this file is compiled and run to make sure it actually
+// runs.  As the API is updated, this file will be updated to demonstrate the
+// new functionality. This project is [on GitHub][ex].
+//
+// If you're trying to write something in C using [libgit2][lg], you will also want
+// to check out the generated [API documentation][ap] and the [Usage Guide][ug]. We've
+// tried to link to the relevant sections of the API docs in each section in this file.
+//
+// **libgit2** only implements the core plumbing functions, not really the higher
+// level porcelain stuff. For a primer on Git Internals that you will need to know
+// to work with Git at this level, check out [Chapter 9][pg] of the Pro Git book.
+//
+// [lg]: http://libgit2.github.com
+// [ap]: http://libgit2.github.com/libgit2/modules.html
+// [ug]: http://libgit2.github.com/api.html
+// [pg]: http://progit.org/book/ch9-0.html
+// [ex]: http://github.com/schacon/libgit2-examples
+
+// ### Includes
+
+// Including the `git2.h` header will include all the other libgit2 headers that you need.
+// It should be the only thing you need to include in order to compile properly and get
+// all the libgit2 API.
+#include <git2.h>
+#include <stdio.h>
+
+int main (int argc, char** argv)
+{
+  // ### Opening the Repository
+
+  // There are a couple of methods for opening a repository, this being the simplest.
+  // There are also [methods][me] for specifying the index file and work tree locations, here
+  // we are assuming they are in the normal places.
+  //
+  // [me]: http://libgit2.github.com/libgit2/group__git__repository.html
+  git_repository *repo;
+  git_repository_open(&repo, "/opt/libgit2-test/.git");
+
+  // ### SHA-1 Value Conversions
+
+  // For our first example, we will convert a 40 character hex value to the 20 byte raw SHA1 value.
+  printf("*Hex to Raw*\n");
+  char hex[] = "fd6e612585290339ea8bf39c692a7ff6a29cb7c3";
+
+  // The `git_oid` is the structure that keeps the SHA value. We will use this throughout the example
+  // for storing the value of the current SHA key we're working with.
+  git_oid oid;
+  git_oid_mkstr(&oid, hex);
+
+  // Once we've converted the string into the oid value, we can get the raw value of the SHA.
+  printf("Raw 20 bytes: [%s]\n", (&oid)->id);
+
+  // Next we will convert the 20 byte raw SHA1 value to a human readable 40 char hex value.
+  printf("\n*Raw to Hex*\n");
+  char out[41];
+  out[40] = '\0';
+
+  // If you have a oid, you can easily get the hex value of the SHA as well.
+  git_oid_fmt(out, &oid);
+  printf("SHA hex string: %s\n", out);
+
+  // ### Working with the Object Database
+  // **libgit2** provides [direct access][odb] to the object database.
+  // The object database is where the actual objects are stored in Git. For 
+  // working with raw objects, we'll need to get this structure from the 
+  // repository.
+  // [odb]: http://libgit2.github.com/libgit2/group__git__odb.html
+  git_odb *odb;
+  odb = git_repository_database(repo);
+
+  // #### Raw Object Reading
+
+  printf("\n*Raw Object Read*\n");
+  git_odb_object *obj;
+  git_otype otype;
+  const unsigned char *data;
+  const char *str_type;
+  int error;
+
+  // We can read raw objects directly from the object database if we have the oid (SHA)
+  // of the object.  This allows us to access objects without knowing thier type and inspect
+  // the raw bytes unparsed.
+  error = git_odb_read(&obj, odb, &oid);
+
+  // A raw object only has three properties - the type (commit, blob, tree or tag), the size
+  // of the raw data and the raw, unparsed data itself.  For a commit or tag, that raw data
+  // is human readable plain ASCII text. For a blob it is just file contents, so it could be
+  // text or binary data. For a tree it is a special binary format, so it's unlikely to be
+  // hugely helpful as a raw object.
+  data = (const unsigned char *)git_odb_object_data(obj);
+  otype = git_odb_object_type(obj);
+
+  // We provide methods to convert from the object type which is an enum, to a string 
+  // representation of that value (and vice-versa).
+  str_type = git_object_type2string(otype);
+  printf("object length and type: %d, %s\n", 
+      (int)git_odb_object_size(obj),
+      str_type);
+
+  // For proper memory management, close the object when you are done with it or it will leak
+  // memory.
+  git_odb_object_close(obj);
+
+  // #### Raw Object Writing
+
+  printf("\n*Raw Object Write*\n");
+
+  // You can also write raw object data to Git. This is pretty cool because it gives you
+  // direct access to the key/value properties of Git.  Here we'll write a new blob object
+  // that just contains a simple string.  Notice that we have to specify the object type as
+  // the `git_otype` enum.
+  git_odb_write(&oid, odb, "test data", sizeof("test data") - 1, GIT_OBJ_BLOB);
+
+  // Now that we've written the object, we can check out what SHA1 was generated when the
+  // object was written to our database.
+  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/group__git__commit.html
+
+  printf("\n*Commit Parsing*\n");
+
+  git_commit *commit;
+  git_oid_mkstr(&oid, "f0877d0b841d75172ec404fc9370173dfffc20d1");
+
+  error = git_commit_lookup(&commit, repo, &oid);
+
+  const git_signature *author, *cmtter;
+  const char *message, *message_short;
+  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 `_message_short`
+  // which gives you just the first line of the commit message.
+  message  = git_commit_message(commit);
+  message_short = git_commit_message_short(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, which is the commit it was based on, and merge commits will have two or more. 
+  // Commits can technically have any number, though it's pretty 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_close(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_close(commit);
+
+  // #### Writing Commits
+  //
+  // libgit2 provides a couple of methods to create commit objects easily as well. There are four
+  // different create signatures, we'll just show one of them here.  You can read about the other
+  // ones in the [commit API docs][cd].
+  // [cd]: http://libgit2.github.com/libgit2/group__git__commit.html
+
+  printf("\n*Commit Writing*\n");
+  git_oid tree_id, parent_id, commit_id;
+
+  // Creating signatures for an authoring identity and time is pretty simple - you will need to have
+  // this to create a commit in order to specify who created it and when.  Default values for the name
+  // and email should be found in the `user.name` and `user.email` configuration options.  See the `config`
+  // section of this example file to see how to access config values.
+  author = git_signature_new("Scott Chacon", "schacon@gmail.com",
+      123456789, 60);
+  cmtter = git_signature_new("Scott A Chacon", "scott@github.com",
+      987654321, 90);
+
+  // Commit objects need a tree to point to and optionally one or more parents.  Here we're creating oid
+  // objects to create the commit with, but you can also use 
+  git_oid_mkstr(&tree_id, "28873d96b4e8f4e33ea30f4c682fd325f7ba56ac");
+  git_oid_mkstr(&parent_id, "f0877d0b841d75172ec404fc9370173dfffc20d1");
+
+  // Here we actually create the commit object with a single call with all the values we need to create
+  // the commit.  The SHA key is written to the `commit_id` variable here.
+  git_commit_create_v(
+    &commit_id, /* out id */
+    repo,
+    NULL, /* do not update the HEAD */
+    author,
+    cmtter,
+    "example commit",
+    &tree_id,
+    1, &parent_id);
+
+  // Now we can take a look at the commit SHA we've generated.
+  git_oid_fmt(out, &commit_id);
+  printf("New Commit: %s\n", out);
+
+  // #### 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/group__git__tag.html
+  printf("\n*Tag Parsing*\n");
+  git_tag *tag;
+  const char *tmessage, *tname;
+  git_otype ttype;
+
+  // We create an oid for the tag object if we know the SHA and look it up in the repository the same
+  // way that we would a commit (or any other) object.
+  git_oid_mkstr(&oid, "bc422d45275aca289c51d79830b45cecebff7c3a");
+
+  error = git_tag_lookup(&tag, repo, &oid);
+
+  // 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_type(tag);    // GIT_OBJ_COMMIT (otype enum)
+  tmessage = git_tag_message(tag); // "tag message\n"
+  printf("Tag Message: %s\n", tmessage);
+
+  git_commit_close(commit);
+
+  // #### 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/group__git__tree.html
+  printf("\n*Tree Parsing*\n");
+
+  git_tree *tree;
+  git_tree_entry *entry;
+  git_object *objt;
+
+  // Create the oid and lookup the tree object just like the other objects.
+  git_oid_mkstr(&oid, "2a741c18ac5ff082a7caaec6e74db3075a1906b5");
+  git_tree_lookup(&tree, repo, &oid);
+
+  // Getting the count of entries in the tree so you can iterate over them if you want to.
+  int cnt = git_tree_entrycount(tree); // 3
+  printf("tree entries: %d\n", cnt);
+
+  entry = git_tree_entry_byindex(tree, 0);
+  printf("Entry name: %s\n", git_tree_entry_name(entry)); // "hello.c"
+
+  // 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, "hello.c");
+  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_2object(&objt, repo, entry); // blob
+
+  // Remember to close the looked-up object once you are done using it
+  git_object_close(objt);
+
+  // #### 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/group__git__blob.html
+
+  printf("\n*Blob Parsing*\n");
+  git_blob *blob;
+
+  git_oid_mkstr(&oid, "af7574ea73f7b166f869ef1a39be126d9a186ae0");
+  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: %d\n", git_blob_rawsize(blob)); // 8
+  git_blob_rawcontent(blob); // "content"
+
+  // ### Revwalking
+  //
+  // The libgit2 [revision walking api][rw] provides methods to traverse the directed graph created
+  // by the parent pointers of the commit objects.  Since all commits point back to the commit that
+  // came directly before them, you can walk this parentage as a graph and find all the commits that
+  // were ancestors of (reachable from) a given starting point.  This can allow you to create `git log`
+  // type functionality.
+  //
+  // [rw]: http://libgit2.github.com/libgit2/group__git__revwalk.html
+
+  printf("\n*Revwalking*\n");
+  git_revwalk *walk;
+  git_commit *wcommit;
+
+  git_oid_mkstr(&oid, "f0877d0b841d75172ec404fc9370173dfffc20d1");
+
+  // To use the revwalker, create a new walker, tell it how you want to sort the output and then push
+  // one or more starting points onto the walker.  If you want to emulate the output of `git log` you
+  // would push the SHA of the commit that HEAD points to into the walker and then start traversing them.
+  // You can also 'hide' commits that you want to stop at or not see any of their ancestors.  So if you
+  // want to emulate `git log branch1..branch2`, you would push the oid of `branch2` and hide the oid
+  // of `branch1`.
+  git_revwalk_new(&walk, repo);
+  git_revwalk_sorting(walk, GIT_SORT_TOPOLOGICAL | GIT_SORT_REVERSE);
+  git_revwalk_push(walk, &oid);
+
+  const git_signature *cauth;
+  const char *cmsg;
+
+  // Now that we have the starting point pushed onto the walker, we can start asking for ancestors. It
+  // will return them in the sorting order we asked for as commit oids.
+  // We can then lookup and parse the commited pointed at by the returned OID;
+  // note that this operation is specially fast since the raw contents of the commit object will
+  // be cached in memory
+  while ((git_revwalk_next(&oid, walk)) == GIT_SUCCESS) {
+    error = git_commit_lookup(&wcommit, repo, &oid);
+    cmsg  = git_commit_message_short(wcommit);
+    cauth = git_commit_author(wcommit);
+    printf("%s (%s)\n", cmsg, cauth->email);
+    git_commit_close(wcommit);
+  }
+
+  // Like the other objects, be sure to free the revwalker when you're done to prevent memory leaks.
+  // Also, make sure that the repository being walked it not deallocated while the walk is in
+  // progress, or it will result in undefined behavior
+  git_revwalk_free(walk);
+
+  // ### Index File Manipulation
+  //
+  // The [index file API][gi] allows you to read, traverse, update and write the Git index file 
+  // (sometimes thought of as the staging area).
+  //
+  // [gi]: http://libgit2.github.com/libgit2/group__git__index.html
+
+  printf("\n*Index Walking*\n");
+
+  git_index *index;
+  unsigned int i, e, ecount;
+
+  // You can either open the index from the standard location in an open repository, as we're doing
+  // here, or you can open and manipulate any index file with `git_index_open_bare()`. The index
+  // for the repository will be located and loaded from disk.
+  git_index_open_inrepo(&index, repo);
+
+  // For each entry in the index, you can get a bunch of information including the SHA (oid), path
+  // and mode which map to the tree objects that are written out.  It also has filesystem properties
+  // to help determine what to inspect for changes (ctime, mtime, dev, ino, uid, gid, file_size and flags)
+  // All these properties are exported publicly in the `git_index_entry` struct
+  ecount = git_index_entrycount(index);
+  for (i = 0; i < ecount; ++i) {
+    git_index_entry *e = git_index_get(index, i);
+
+    printf("path: %s\n", e->path);
+    printf("mtime: %d\n", (int)e->mtime.seconds);
+    printf("fs: %d\n", (int)e->file_size);
+  }
+
+  git_index_free(index);
+
+  // ### References
+  //
+  // The [reference API][ref] allows you to list, resolve, create and update references such as
+  // branches, tags and remote references (everything in the .git/refs directory).
+  //
+  // [ref]: http://libgit2.github.com/libgit2/refs_8h.html
+
+  printf("\n*Reference Listing*\n");
+
+  // Here we will implement something like `git for-each-ref` simply listing out all available
+  // references and the object SHA they resolve to.
+  git_strarray ref_list;
+  git_reference_listall(&ref_list, repo, GIT_REF_LISTALL);
+
+  const char *refname, *reftarget;
+  git_reference *ref;
+
+  // Now that we have the list of reference names, we can lookup each ref one at a time and
+  // resolve them to the SHA, then print both values out.
+  for (i = 0; i < ref_list.count; ++i) {
+    refname = ref_list.strings[i];
+    git_reference_lookup(&ref, repo, refname);
+
+    switch (git_reference_type(ref)) {
+    case GIT_REF_OID:
+      git_oid_fmt(out, git_reference_oid(ref));
+      printf("%s [%s]\n", refname, out);
+      break;
+
+    case GIT_REF_SYMBOLIC:
+      printf("%s => %s\n", refname, git_reference_target(ref));
+      break;
+    }
+  }
+
+  git_strarray_free(&ref_list);
+
+  // Finally, when you're done with the repository, you can free it as well.
+  git_repository_free(repo);
+}
+
diff --git a/examples/showindex.c b/examples/showindex.c
new file mode 100644
index 000000000..908a114f4
--- /dev/null
+++ b/examples/showindex.c
@@ -0,0 +1,43 @@
+#include <git2.h>
+#include <stdio.h>
+
+int main (int argc, char** argv)
+{
+  git_repository *repo;
+  git_index *index;
+  unsigned int i, e, ecount;
+  git_index_entry **entries;
+  git_oid oid;
+
+  char out[41];
+  out[40] = '\0';
+
+  git_repository_open(&repo, "/tmp/gittalk/.git");
+
+  git_index_open_inrepo(&index, repo);
+  git_index_read(index);
+
+  ecount = git_index_entrycount(index);
+  for (i = 0; i < ecount; ++i) {
+    git_index_entry *e = git_index_get(index, i);
+
+    oid = e->oid;
+    git_oid_fmt(out, &oid);
+
+    printf("File Path: %s\n", e->path);
+    printf(" Blob SHA: %s\n", out);
+    printf("File Size: %d\n", (int)e->file_size);
+    printf("   Device: %d\n", (int)e->dev);
+    printf("    Inode: %d\n", (int)e->ino);
+    printf("      UID: %d\n", (int)e->uid);
+    printf("      GID: %d\n", (int)e->gid);
+    printf("    ctime: %d\n", (int)e->ctime.seconds);
+    printf("    mtime: %d\n", (int)e->mtime.seconds);
+    printf("\n");
+  }
+
+  git_index_free(index);
+
+  git_repository_free(repo);
+}
+