thodg/libgit2

diff --git a/src/git/tree.h b/src/git/tree.h
index 32fd652..bec49f2 100644
--- a/src/git/tree.h
+++ b/src/git/tree.h
@@ -65,7 +65,7 @@ GIT_EXTERN(size_t) git_tree_entrycount(git_tree *tree);
  * @param filename the filename of the desired entry
  * @return the tree entry; NULL if not found
  */
-GIT_EXTERN(const git_tree_entry *) git_tree_entry_byname(git_tree *tree, const char *filename);
+GIT_EXTERN(git_tree_entry *) git_tree_entry_byname(git_tree *tree, const char *filename);
 
 /**
  * Lookup a tree entry by its position in the tree
@@ -73,35 +73,107 @@ GIT_EXTERN(const git_tree_entry *) git_tree_entry_byname(git_tree *tree, const c
  * @param idx the position in the entry list
  * @return the tree entry; NULL if not found
  */
-GIT_EXTERN(const git_tree_entry *) git_tree_entry_byindex(git_tree *tree, int idx);
+GIT_EXTERN(git_tree_entry *) git_tree_entry_byindex(git_tree *tree, int idx);
 
 /**
  * Get the UNIX file attributes of a tree entry
  * @param entry a tree entry
  * @return attributes as an integer
  */
-GIT_EXTERN(unsigned int) git_tree_entry_attributes(const git_tree_entry *entry);
+GIT_EXTERN(unsigned int) git_tree_entry_attributes(git_tree_entry *entry);
 
 /**
  * Get the filename of a tree entry
  * @param entry a tree entry
  * @return the name of the file
  */
-GIT_EXTERN(const char *) git_tree_entry_name(const git_tree_entry *entry);
+GIT_EXTERN(const char *) git_tree_entry_name(git_tree_entry *entry);
 
 /**
  * Get the id of the object pointed by the entry
  * @param entry a tree entry
  * @return the oid of the object
  */
-GIT_EXTERN(const git_oid *) git_tree_entry_id(const git_tree_entry *entry);
+GIT_EXTERN(const git_oid *) git_tree_entry_id(git_tree_entry *entry);
 
 /**
  * Convert a tree entry to the git_object it points too.
  * @param entry a tree entry
  * @return a reference to the pointed object in the repository
  */
-GIT_EXTERN(git_object *) git_tree_entry_2object(const git_tree_entry *entry);
+GIT_EXTERN(git_object *) git_tree_entry_2object(git_tree_entry *entry);
+
+/**
+ * Add a new entry to a tree.
+ *
+ * This will mark the tree as modified; the new entry will
+ * be written back to disk on the next git_object_write()
+ *
+ * @param tree Tree object to store the entry
+ * @iparam id OID for the tree entry
+ * @param filename Filename for the tree entry
+ * @param attributes UNIX file attributes for the entry
+ */
+GIT_EXTERN(void) git_tree_add_entry(git_tree *tree, const git_oid *id, const char *filename, int attributes);
+
+/**
+ * Remove an entry by its index.
+ *
+ * Index must be >= 0 and < than git_tree_entrycount().
+ *
+ * This will mark the tree as modified; the modified entry will
+ * be written back to disk on the next git_object_write()
+ *
+ * @param tree Tree where to remove the entry
+ * @param idx index of the entry
+ * @return 0 on successful removal; GIT_ENOTFOUND if the entry wasn't found
+ */
+GIT_EXTERN(int) git_tree_remove_entry_byindex(git_tree *tree, int idx);
+
+/**
+ * Remove an entry by its filename.
+ *
+ * This will mark the tree as modified; the modified entry will
+ * be written back to disk on the next git_object_write()
+ *
+ * @param tree Tree where to remove the entry
+ * @param filename File name of the entry
+ * @return 0 on successful removal; GIT_ENOTFOUND if the entry wasn't found
+ */
+GIT_EXTERN(int) git_tree_remove_entry_byname(git_tree *tree, const char *filename);
+
+/**
+ * Change the SHA1 id of a tree entry.
+ *
+ * This will mark the tree that contains the entry as modified; 
+ * the modified entry will be written back to disk on the next git_object_write()
+ *
+ * @param entry Entry object which will be modified
+ * @param oid new SHA1 oid for the entry
+ */
+GIT_EXTERN(void) git_tree_entry_set_id(git_tree_entry *entry, const git_oid *oid);
+
+/**
+ * Change the filename of a tree entry.
+ *
+ * This will mark the tree that contains the entry as modified; 
+ * the modified entry will be written back to disk on the next git_object_write()
+ *
+ * @param entry Entry object which will be modified
+ * @param oid new filename for the entry
+ */
+GIT_EXTERN(void) git_tree_entry_set_name(git_tree_entry *entry, const char *name);
+
+/**
+ * Change the attributes of a tree entry.
+ *
+ * This will mark the tree that contains the entry as modified; 
+ * the modified entry will be written back to disk on the next git_object_write()
+ *
+ * @param entry Entry object which will be modified
+ * @param oid new attributes for the entry
+ */
+GIT_EXTERN(void) git_tree_entry_set_attributes(git_tree_entry *entry, int attr);
 
 /** @} */
 GIT_END_DECL
diff --git a/src/repository.c b/src/repository.c
index dc1fe0e..22f2bba 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -270,6 +270,9 @@ int git_object_write(git_object *object)
 		break;
 
 	case GIT_OBJ_TREE:
+		error = git_tree__writeback((git_tree *)object, source);
+		break;
+
 	case GIT_OBJ_TAG:
 	default:
 		error = GIT_ERROR;
diff --git a/src/tree.c b/src/tree.c
index 670f998..43a5042 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -29,12 +29,49 @@
 #include "tree.h"
 #include "git/repository.h"
 
+static void resize_tree_array(git_tree *tree)
+{
+	git_tree_entry **new_entries;
+
+	tree->array_size = tree->array_size * 2;
+
+	new_entries = git__malloc(tree->array_size * sizeof(git_tree_entry *));
+	memcpy(new_entries, tree->entries, tree->entry_count * sizeof(git_tree_entry *));
+
+	free(tree->entries);
+	tree->entries = new_entries;
+}
+
+int entry_cmp(const void *key, const void *array_member)
+{
+	const char *filename = (const char *)key;
+	const git_tree_entry *entry = *(const git_tree_entry **)(array_member);
+
+	return strcmp(filename, entry->filename);
+}
+
+int entry_sort_cmp(const void *a, const void *b)
+{
+	const git_tree_entry *entry_a = *(const git_tree_entry **)(a);
+	const git_tree_entry *entry_b = *(const git_tree_entry **)(b);
+
+	return strcmp(entry_a->filename, entry_b->filename);
+}
+
+static void entry_resort(git_tree *tree)
+{
+	qsort(tree->entries, tree->entry_count, sizeof(git_tree_entry *), entry_sort_cmp);
+}
+
+
+
+
 void git_tree__free(git_tree *tree)
 {
 	size_t i;
 
 	for (i = 0; i < tree->entry_count; ++i)
-		free(tree->entries[i].filename);
+		free(tree->entries[i]);
 
 	free(tree->entries);
 	free(tree);
@@ -55,45 +92,62 @@ git_tree *git_tree_lookup(git_repository *repo, const git_oid *id)
 	return (git_tree *)git_repository_lookup(repo, id, GIT_OBJ_TREE);
 }
 
-unsigned int git_tree_entry_attributes(const git_tree_entry *entry)
+void git_tree_entry_set_attributes(git_tree_entry *entry, int attr)
 {
-	return entry->attr;
+	assert(entry && entry->owner);
+
+	entry->attr = attr;
+	entry->owner->object.modified = 1;
 }
 
-const char *git_tree_entry_name(const git_tree_entry *entry)
+void git_tree_entry_set_name(git_tree_entry *entry, const char *name)
 {
-	return entry->filename;
+	assert(entry && entry->owner);
+
+	strncpy(entry->filename, name, GIT_TREE_MAX_FILENAME);
+	entry_resort(entry->owner);
+	entry->owner->object.modified = 1;
 }
 
-const git_oid *git_tree_entry_id(const git_tree_entry *entry)
+void git_tree_entry_set_id(git_tree_entry *entry, const git_oid *oid)
 {
-	return &entry->oid;
+	assert(entry && entry->owner);
+
+	git_oid_cpy(&entry->oid, oid);
+	entry->owner->object.modified = 1;
 }
 
-git_object *git_tree_entry_2object(const git_tree_entry *entry)
+unsigned int git_tree_entry_attributes(git_tree_entry *entry)
 {
-	return git_repository_lookup(entry->owner->object.repo, &entry->oid, GIT_OBJ_ANY);
+	return entry->attr;
 }
 
-int entry_cmp(const void *key, const void *array_member)
+const char *git_tree_entry_name(git_tree_entry *entry)
 {
-	const char *filename = (const char *)key;
-	const git_tree_entry *entry = (const git_tree_entry *)array_member;
+	return entry->filename;
+}
 
-	return strcmp(filename, entry->filename);
+const git_oid *git_tree_entry_id(git_tree_entry *entry)
+{
+	return &entry->oid;
 }
 
-const git_tree_entry *git_tree_entry_byname(git_tree *tree, const char *filename)
+git_object *git_tree_entry_2object(git_tree_entry *entry)
 {
-	return bsearch(filename, tree->entries, tree->entry_count, sizeof(git_tree_entry), entry_cmp);
+	return git_repository_lookup(entry->owner->object.repo, &entry->oid, GIT_OBJ_ANY);
 }
 
-const git_tree_entry *git_tree_entry_byindex(git_tree *tree, int idx)
+git_tree_entry *git_tree_entry_byname(git_tree *tree, const char *filename)
+{
+	return *(git_tree_entry **)bsearch(filename, tree->entries, tree->entry_count, sizeof(git_tree_entry *), entry_cmp);
+}
+
+git_tree_entry *git_tree_entry_byindex(git_tree *tree, int idx)
 {
 	if (tree->entries == NULL)
 		return NULL;
 
-	return (idx >= 0 && idx < (int)tree->entry_count) ? &tree->entries[idx] : NULL;
+	return (idx >= 0 && idx < (int)tree->entry_count) ? tree->entries[idx] : NULL;
 }
 
 size_t git_tree_entrycount(git_tree *tree)
@@ -101,16 +155,97 @@ size_t git_tree_entrycount(git_tree *tree)
 	return tree->entry_count;
 }
 
+void git_tree_add_entry(git_tree *tree, const git_oid *id, const char *filename, int attributes)
+{
+	git_tree_entry *entry;
+
+	if (tree->entry_count >= tree->array_size)
+		resize_tree_array(tree);
+
+	if ((entry = git__malloc(sizeof(git_tree_entry))) == NULL)
+		return;
+
+	memset(entry, 0x0, sizeof(git_tree_entry));
+
+	strncpy(entry->filename, filename, GIT_TREE_MAX_FILENAME);
+	git_oid_cpy(&entry->oid, id);
+	entry->attr = attributes;
+	entry->owner = tree;
+
+	tree->entries[tree->entry_count++] = entry;
+	entry_resort(tree);
+
+	tree->object.modified = 1;
+}
+
+int git_tree_remove_entry_byindex(git_tree *tree, int idx)
+{
+	git_tree_entry *remove_ptr;
+
+	if (idx < 0 || idx >= (int)tree->entry_count)
+		return GIT_ENOTFOUND;
+
+	remove_ptr = tree->entries[idx];
+	tree->entries[idx] = tree->entries[--tree->entry_count];
+
+	free(remove_ptr);
+	entry_resort(tree);
+
+	tree->object.modified = 1;
+	return GIT_SUCCESS;
+}
+
+int git_tree_remove_entry_byname(git_tree *tree, const char *filename)
+{
+	git_tree_entry **entry_ptr;
+	int idx;
+
+	entry_ptr = bsearch(filename, tree->entries, tree->entry_count, sizeof(git_tree_entry *), entry_cmp);
+	if (entry_ptr == NULL)
+		return GIT_ENOTFOUND;
+
+	idx = (int)(entry_ptr - tree->entries);
+	return git_tree_remove_entry_byindex(tree, idx);
+}
+
+int git_tree__writeback(git_tree *tree, git_odb_source *src)
+{
+	size_t i;
+
+	if (tree->entries == NULL)
+		return GIT_ERROR;
+
+	entry_resort(tree);
+
+	for (i = 0; i < tree->entry_count; ++i) {
+		git_tree_entry *entry;
+		entry = tree->entries[i];
+	
+		git__source_printf(src, "%06o %s\0", entry->attr, entry->filename);
+		git__source_write(src, entry->oid.id, GIT_OID_RAWSZ);
+	}
+
+	return GIT_SUCCESS;
+}
+
+
 int git_tree__parse(git_tree *tree)
 {
 	static const size_t avg_entry_size = 40;
 
 	int error = 0;
 	char *buffer, *buffer_end;
-	size_t entries_size;
 
-	if (tree->entries != NULL)
-		return GIT_SUCCESS;
+	assert(!tree->object.in_memory);
+
+	if (tree->entries != NULL) {
+		size_t i;
+
+		for (i = 0; i < tree->entry_count; ++i)
+			free(tree->entries[i]);
+
+		free(tree->entries);
+	}
 
 	error = git_object__source_open((git_object *)tree);
 	if (error < 0)
@@ -120,27 +255,24 @@ int git_tree__parse(git_tree *tree)
 	buffer_end = buffer + tree->object.source.raw.len;
 
 	tree->entry_count = 0;
-	entries_size = (tree->object.source.raw.len / avg_entry_size) + 1;
-	tree->entries = git__malloc(entries_size * sizeof(git_tree_entry));
+	tree->array_size = (tree->object.source.raw.len / avg_entry_size) + 1;
+	tree->entries = git__malloc(tree->array_size * sizeof(git_tree_entry *));
 
 	while (buffer < buffer_end) {
 		git_tree_entry *entry;
 
-		if (tree->entry_count >= entries_size) {
-			git_tree_entry *new_entries;
-
-			entries_size = entries_size * 2;
-
-			new_entries = git__malloc(entries_size * sizeof(git_tree_entry));
-			memcpy(new_entries, tree->entries, tree->entry_count * sizeof(git_tree_entry));
+		if (tree->entry_count >= tree->array_size)
+			resize_tree_array(tree);
 
-			free(tree->entries);
-			tree->entries = new_entries;
+		entry = git__malloc(sizeof(git_tree_entry));
+		if (entry == NULL) {
+			error = GIT_ENOMEM;
+			break;
 		}
 
-		entry = &tree->entries[tree->entry_count++];
-		entry->owner = tree;
+		tree->entries[tree->entry_count++] = entry;
 
+		entry->owner = tree;
 		entry->attr = strtol(buffer, &buffer, 8);
 
 		if (*buffer++ != ' ') {
@@ -148,13 +280,12 @@ int git_tree__parse(git_tree *tree)
 			break;
 		}
 
-		entry->filename = git__strdup(buffer);
+		strncpy(entry->filename, buffer, GIT_TREE_MAX_FILENAME);
 
-		if (entry->filename == NULL) {
-			error = GIT_EOBJCORRUPTED;
-		}
+		while (buffer < buffer_end && *buffer != 0)
+			buffer++;
 
-		buffer += strlen(entry->filename) + 1;
+		buffer++;
 
 		git_oid_mkraw(&entry->oid, (const unsigned char *)buffer);
 		buffer += GIT_OID_RAWSZ;
diff --git a/src/tree.h b/src/tree.h
index dd15b9b..118d2c3 100644
--- a/src/tree.h
+++ b/src/tree.h
@@ -4,9 +4,11 @@
 #include <git/tree.h>
 #include "repository.h"
 
+#define GIT_TREE_MAX_FILENAME 255
+
 struct git_tree_entry {
 	unsigned int attr;
-	char *filename;
+	char filename[GIT_TREE_MAX_FILENAME];
 	git_oid oid;
 
 	git_tree *owner;
@@ -15,11 +17,13 @@ struct git_tree_entry {
 struct git_tree {
 	git_object object;
 
-	git_tree_entry *entries;
+	git_tree_entry **entries;
 	size_t entry_count;
+	size_t array_size;
 };
 
 void git_tree__free(git_tree *tree);
 int git_tree__parse(git_tree *tree);
+int git_tree__writeback(git_tree *tree, git_odb_source *src);
 
 #endif
diff --git a/tests/t0901-readtree.c b/tests/t0901-readtree.c
index 307bbea..c28ad23 100644
--- a/tests/t0901-readtree.c
+++ b/tests/t0901-readtree.c
@@ -14,7 +14,7 @@ BEGIN_TEST(tree_read_test)
 	git_oid id;
 	git_repository *repo;
 	git_tree *tree;
-	const git_tree_entry *entry;
+	git_tree_entry *entry;
 
 	must_pass(git_odb_open(&db, odb_dir));
 
@@ -35,6 +35,7 @@ BEGIN_TEST(tree_read_test)
 
 	must_be_true(strcmp(git_tree_entry_name(entry), "README") == 0);
 
+
 	must_be_true(git_tree_entry_2object(entry) != NULL);
 
 	git_repository_free(repo);