Add cat-file example and increase const use in API This adds an example implementation that emulates git cat-file. It is a convenient and relatively simple example of getting data out of a repository. Implementing this also revealed that there are a number of APIs that are still not using const pointers to objects that really ought to be. The main cause of this is that `git_vector_bsearch` may need to call `git_vector_sort` before doing the search, so a const pointer to the vector is not allowed. However, for tree objects, with a little care, we can ensure that the vector of tree entries is always sorted and allow lookups to take a const pointer. Also, the missing const in commit objects just looks like an oversight.
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diff --git a/examples/Makefile b/examples/Makefile
index 2c18731..c5d5555 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -3,7 +3,7 @@
CC = gcc
CFLAGS = -g -I../include -I../src -Wall -Wextra -Wmissing-prototypes -Wno-missing-field-initializers
LFLAGS = -L../build -lgit2 -lz
-APPS = general showindex diff rev-list
+APPS = general showindex diff rev-list cat-file
all: $(APPS)
diff --git a/examples/cat-file.c b/examples/cat-file.c
new file mode 100644
index 0000000..ebb6cb0
--- /dev/null
+++ b/examples/cat-file.c
@@ -0,0 +1,229 @@
+#include <stdio.h>
+#include <git2.h>
+#include <stdlib.h>
+#include <string.h>
+
+static git_repository *g_repo;
+
+static void check(int error, const char *message)
+{
+ if (error) {
+ fprintf(stderr, "%s (%d)\n", message, error);
+ exit(1);
+ }
+}
+
+static void usage(const char *message, const char *arg)
+{
+ if (message && arg)
+ fprintf(stderr, "%s: %s\n", message, arg);
+ else if (message)
+ fprintf(stderr, "%s\n", message);
+ fprintf(stderr, "usage: cat-file (-t | -s | -e | -p) [<options>] <object>\n");
+ exit(1);
+}
+
+static int check_str_param(
+ const char *arg, const char *pattern, const char **val)
+{
+ size_t len = strlen(pattern);
+ if (strncmp(arg, pattern, len))
+ return 0;
+ *val = (const char *)(arg + len);
+ return 1;
+}
+
+static void print_signature(const char *header, const git_signature *sig)
+{
+ char sign;
+ int offset, hours, minutes;
+
+ if (!sig)
+ return;
+
+ offset = sig->when.offset;
+ if (offset < 0) {
+ sign = '-';
+ offset = -offset;
+ } else {
+ sign = '+';
+ }
+
+ hours = offset / 60;
+ minutes = offset % 60;
+
+ printf("%s %s <%s> %ld %c%02d%02d\n",
+ header, sig->name, sig->email, (long)sig->when.time,
+ sign, hours, minutes);
+}
+
+static void show_blob(const git_blob *blob)
+{
+ /* ? Does this need crlf filtering? */
+ fwrite(git_blob_rawcontent(blob), git_blob_rawsize(blob), 1, stdout);
+}
+
+static void show_tree(const git_tree *tree)
+{
+ size_t i, max_i = (int)git_tree_entrycount(tree);
+ char oidstr[GIT_OID_HEXSZ + 1];
+ const git_tree_entry *te;
+
+ for (i = 0; i < max_i; ++i) {
+ te = git_tree_entry_byindex(tree, i);
+
+ git_oid_tostr(oidstr, sizeof(oidstr), git_tree_entry_id(te));
+
+ printf("%06o %s %s\t%s\n",
+ git_tree_entry_filemode(te),
+ git_object_type2string(git_tree_entry_type(te)),
+ oidstr, git_tree_entry_name(te));
+ }
+}
+
+static void show_commit(const git_commit *commit)
+{
+ unsigned int i, max_i;
+ char oidstr[GIT_OID_HEXSZ + 1];
+
+ git_oid_tostr(oidstr, sizeof(oidstr), git_commit_tree_id(commit));
+ printf("tree %s\n", oidstr);
+
+ max_i = (unsigned int)git_commit_parentcount(commit);
+ for (i = 0; i < max_i; ++i) {
+ git_oid_tostr(oidstr, sizeof(oidstr), git_commit_parent_id(commit, i));
+ printf("parent %s\n", oidstr);
+ }
+
+ print_signature("author", git_commit_author(commit));
+ print_signature("committer", git_commit_committer(commit));
+
+ if (git_commit_message(commit))
+ printf("\n%s\n", git_commit_message(commit));
+}
+
+static void show_tag(const git_tag *tag)
+{
+ char oidstr[GIT_OID_HEXSZ + 1];
+
+ git_oid_tostr(oidstr, sizeof(oidstr), git_tag_target_id(tag));;
+ printf("object %s\n", oidstr);
+ printf("type %s\n", git_object_type2string(git_tag_target_type(tag)));
+ printf("tag %s\n", git_tag_name(tag));
+ print_signature("tagger", git_tag_tagger(tag));
+
+ if (git_tag_message(tag))
+ printf("\n%s\n", git_tag_message(tag));
+}
+
+enum {
+ SHOW_TYPE = 1,
+ SHOW_SIZE = 2,
+ SHOW_NONE = 3,
+ SHOW_PRETTY = 4
+};
+
+int main(int argc, char *argv[])
+{
+ const char *dir = ".", *rev = NULL;
+ int i, action = 0, verbose = 0;
+ git_object *obj = NULL;
+ char oidstr[GIT_OID_HEXSZ + 1];
+
+ git_threads_init();
+
+ for (i = 1; i < argc; ++i) {
+ char *a = argv[i];
+
+ if (a[0] != '-') {
+ if (rev != NULL)
+ usage("Only one rev should be provided", NULL);
+ else
+ rev = a;
+ }
+ else if (!strcmp(a, "-t"))
+ action = SHOW_TYPE;
+ else if (!strcmp(a, "-s"))
+ action = SHOW_SIZE;
+ else if (!strcmp(a, "-e"))
+ action = SHOW_NONE;
+ else if (!strcmp(a, "-p"))
+ action = SHOW_PRETTY;
+ else if (!strcmp(a, "-q"))
+ verbose = 0;
+ else if (!strcmp(a, "-v"))
+ verbose = 1;
+ else if (!strcmp(a, "--help") || !strcmp(a, "-h"))
+ usage(NULL, NULL);
+ else if (!check_str_param(a, "--git-dir=", &dir))
+ usage("Unknown option", a);
+ }
+
+ if (!action || !rev)
+ usage(NULL, NULL);
+
+ check(git_repository_open_ext(&g_repo, dir, 0, NULL),
+ "Could not open repository");
+
+ if (git_revparse_single(&obj, g_repo, rev) < 0) {
+ fprintf(stderr, "Could not resolve '%s'\n", rev);
+ exit(1);
+ }
+ if (verbose) {
+ char oidstr[GIT_OID_HEXSZ + 1];
+ git_oid_tostr(oidstr, sizeof(oidstr), git_object_id(obj));
+
+ printf("%s %s\n--\n",
+ git_object_type2string(git_object_type(obj)), oidstr);
+ }
+
+ switch (action) {
+ case SHOW_TYPE:
+ printf("%s\n", git_object_type2string(git_object_type(obj)));
+ break;
+ case SHOW_SIZE: {
+ git_odb *odb;
+ git_odb_object *odbobj;
+
+ check(git_repository_odb(&odb, g_repo), "Could not open ODB");
+ check(git_odb_read(&odbobj, odb, git_object_id(obj)),
+ "Could not find obj");
+
+ printf("%ld\n", (long)git_odb_object_size(odbobj));
+
+ git_odb_object_free(odbobj);
+ git_odb_free(odb);
+ }
+ break;
+ case SHOW_NONE:
+ /* just want return result */
+ break;
+ case SHOW_PRETTY:
+
+ switch (git_object_type(obj)) {
+ case GIT_OBJ_BLOB:
+ show_blob((const git_blob *)obj);
+ break;
+ case GIT_OBJ_COMMIT:
+ show_commit((const git_commit *)obj);
+ break;
+ case GIT_OBJ_TREE:
+ show_tree((const git_tree *)obj);
+ break;
+ case GIT_OBJ_TAG:
+ show_tag((const git_tag *)obj);
+ break;
+ default:
+ printf("unknown %s\n", oidstr);
+ break;
+ }
+ break;
+ }
+
+ git_object_free(obj);
+ git_repository_free(g_repo);
+
+ git_threads_shutdown();
+
+ return 0;
+}
diff --git a/include/git2/commit.h b/include/git2/commit.h
index a420ba6..20b345f 100644
--- a/include/git2/commit.h
+++ b/include/git2/commit.h
@@ -164,7 +164,10 @@ GIT_EXTERN(unsigned int) git_commit_parentcount(const git_commit *commit);
* @param n the position of the parent (from 0 to `parentcount`)
* @return 0 or an error code
*/
-GIT_EXTERN(int) git_commit_parent(git_commit **out, git_commit *commit, unsigned int n);
+GIT_EXTERN(int) git_commit_parent(
+ git_commit **out,
+ const git_commit *commit,
+ unsigned int n);
/**
* Get the oid of a specified parent for a commit. This is different from
@@ -175,7 +178,9 @@ GIT_EXTERN(int) git_commit_parent(git_commit **out, git_commit *commit, unsigned
* @param n the position of the parent (from 0 to `parentcount`)
* @return the id of the parent, NULL on error.
*/
-GIT_EXTERN(const git_oid *) git_commit_parent_id(git_commit *commit, unsigned int n);
+GIT_EXTERN(const git_oid *) git_commit_parent_id(
+ const git_commit *commit,
+ unsigned int n);
/**
* Get the commit object that is the <n>th generation ancestor
diff --git a/include/git2/tree.h b/include/git2/tree.h
index 6ad7220..d673f50 100644
--- a/include/git2/tree.h
+++ b/include/git2/tree.h
@@ -97,7 +97,7 @@ GIT_EXTERN(size_t) git_tree_entrycount(const git_tree *tree);
* @return the tree entry; NULL if not found
*/
GIT_EXTERN(const git_tree_entry *) git_tree_entry_byname(
- git_tree *tree, const char *filename);
+ const git_tree *tree, const char *filename);
/**
* Lookup a tree entry by its position in the tree
@@ -110,7 +110,7 @@ GIT_EXTERN(const git_tree_entry *) git_tree_entry_byname(
* @return the tree entry; NULL if not found
*/
GIT_EXTERN(const git_tree_entry *) git_tree_entry_byindex(
- git_tree *tree, size_t idx);
+ const git_tree *tree, size_t idx);
/**
* Lookup a tree entry by SHA value.
@@ -141,7 +141,7 @@ GIT_EXTERN(const git_tree_entry *) git_tree_entry_byoid(
*/
GIT_EXTERN(int) git_tree_entry_bypath(
git_tree_entry **out,
- git_tree *root,
+ const git_tree *root,
const char *path);
/**
diff --git a/src/commit.c b/src/commit.c
index be6e32c..1ab9b34 100644
--- a/src/commit.c
+++ b/src/commit.c
@@ -266,14 +266,16 @@ int git_commit_tree(git_tree **tree_out, const git_commit *commit)
return git_tree_lookup(tree_out, commit->object.repo, &commit->tree_id);
}
-const git_oid *git_commit_parent_id(git_commit *commit, unsigned int n)
+const git_oid *git_commit_parent_id(
+ const git_commit *commit, unsigned int n)
{
assert(commit);
return git_vector_get(&commit->parent_ids, n);
}
-int git_commit_parent(git_commit **parent, git_commit *commit, unsigned int n)
+int git_commit_parent(
+ git_commit **parent, const git_commit *commit, unsigned int n)
{
const git_oid *parent_id;
assert(commit);
diff --git a/src/tree.c b/src/tree.c
index a48b322..10d1314 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -271,25 +271,27 @@ int git_tree_entry_to_object(
}
static const git_tree_entry *entry_fromname(
- git_tree *tree, const char *name, size_t name_len)
+ const git_tree *tree, const char *name, size_t name_len)
{
size_t idx;
- if (tree_key_search(&idx, &tree->entries, name, name_len) < 0)
+ assert(tree->entries.sorted); /* be safe when we cast away constness */
+
+ if (tree_key_search(&idx, (git_vector *)&tree->entries, name, name_len) < 0)
return NULL;
return git_vector_get(&tree->entries, idx);
}
const git_tree_entry *git_tree_entry_byname(
- git_tree *tree, const char *filename)
+ const git_tree *tree, const char *filename)
{
assert(tree && filename);
return entry_fromname(tree, filename, strlen(filename));
}
const git_tree_entry *git_tree_entry_byindex(
- git_tree *tree, size_t idx)
+ const git_tree *tree, size_t idx)
{
assert(tree);
return git_vector_get(&tree->entries, idx);
@@ -311,9 +313,9 @@ const git_tree_entry *git_tree_entry_byoid(
return NULL;
}
-int git_tree__prefix_position(git_tree *tree, const char *path)
+int git_tree__prefix_position(const git_tree *tree, const char *path)
{
- git_vector *entries = &tree->entries;
+ const git_vector *entries = &tree->entries;
struct tree_key_search ksearch;
size_t at_pos;
@@ -323,8 +325,11 @@ int git_tree__prefix_position(git_tree *tree, const char *path)
ksearch.filename = path;
ksearch.filename_len = strlen(path);
+ assert(tree->entries.sorted); /* be safe when we cast away constness */
+
/* Find tree entry with appropriate prefix */
- git_vector_bsearch2(&at_pos, entries, &homing_search_cmp, &ksearch);
+ git_vector_bsearch2(
+ &at_pos, (git_vector *)entries, &homing_search_cmp, &ksearch);
for (; at_pos < entries->length; ++at_pos) {
const git_tree_entry *entry = entries->contents[at_pos];
@@ -408,6 +413,8 @@ int git_tree__parse(void *_tree, git_odb_object *odb_obj)
buffer += GIT_OID_RAWSZ;
}
+ git_vector_sort(&tree->entries);
+
return 0;
}
@@ -796,7 +803,7 @@ static size_t subpath_len(const char *path)
int git_tree_entry_bypath(
git_tree_entry **entry_out,
- git_tree *root,
+ const git_tree *root,
const char *path)
{
int error = 0;
diff --git a/src/tree.h b/src/tree.h
index 7cb2dd3..f07039a 100644
--- a/src/tree.h
+++ b/src/tree.h
@@ -47,7 +47,7 @@ int git_tree__parse(void *tree, git_odb_object *obj);
* @param prefix the beginning of a path to find in the tree.
* @return index of the first item at or after the given prefix.
*/
-int git_tree__prefix_position(git_tree *tree, const char *prefix);
+int git_tree__prefix_position(const git_tree *tree, const char *prefix);
/**