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#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <git2.h>
enum match_result
{
MATCH_RESULT_INIT,
MATCH_RESULT_ROOT,
MATCH_RESULT_COMMIT,
MATCH_RESULT_ANYTHING,
MATCH_RESULT_PKGVER,
};
static inline size_t minimum(size_t lhs, size_t rhs);
static char* relative_path_in_current_dir(git_repository* repo, const char* filename);
static int try_git(int err, const char* msg);
static int match_line(const git_diff_delta* delta, const git_diff_hunk* hunk, const git_diff_line* line, void* payload);
/// Returns the smaller value from *lhs* and *rhs*.
size_t
minimum(const size_t lhs, const size_t rhs)
{
return lhs > rhs ? rhs : lhs;
}
/// Finds the relative path of *filename* from the workdir of *repo*.
char*
relative_path_in_current_dir(git_repository* repo, const char* filename)
{
const long maximum = pathconf(".", _PC_PATH_MAX);
size_t len = 0 > maximum ? 1024 : maximum;
char* buf = NULL;
char* cwd = NULL;
for (; NULL == cwd && 1024 * 50 > len; len *= 2) {
if (NULL == (cwd = realloc(buf, len))) {
if (NULL != buf)
free(buf);
return NULL;
}
buf = cwd;
cwd = getcwd(buf, len);
if (NULL == cwd && ERANGE != errno) {
free(buf);
return NULL;
}
}
const char* workdir = git_repository_workdir(repo);
const size_t prefix = minimum(strlen(cwd), strlen(workdir));
if (0 != strncmp(cwd, workdir, prefix)) {
free(cwd);
return NULL;
}
const size_t relative = strlen(cwd + prefix);
if (NULL == (buf = malloc(relative + strlen(filename) + 2))) {
free(cwd);
return NULL;
}
strcpy(buf, cwd + prefix);
if (0 < relative)
strcat(buf, "/");
strcat(buf, filename);
free(cwd);
return buf;
}
/// If *err* is considered erroneous in context of libgit2 return code, print a message describing it, and prefix it
/// with *msg* if it is not NULL.
int
try_git(const int err, const char* msg)
{
if (0 > err) {
const git_error* e = git_error_last();
if (NULL != msg)
dprintf(2, "%s: ", msg);
dprintf(2, "%s\n", e->message);
exit(1);
}
return err;
}
/// Callback for git_diff_foreach. Check each line reported by the diff looking for "pkgver" occurrance. If found, set
/// *payload* to MATCH_RESULT_PKGVER, otherwise set it to MATCH_RESULT_ANYTHING, but only if it is not set to
/// MATCH_RESULT_PKGVER already.
int
match_line(const git_diff_delta* delta, const git_diff_hunk* hunk, const git_diff_line* line, void* payload)
{
(void) delta;
(void) hunk;
static const char* const PKGVER = "pkgver";
static const size_t PKGVER_LEN = 6;
enum match_result* match = (enum match_result*) payload;
switch (line->origin) {
case GIT_DIFF_LINE_ADDITION:
case GIT_DIFF_LINE_DELETION:
if (PKGVER_LEN <= line->content_len && 0 == strncmp(line->content, PKGVER, PKGVER_LEN))
*match = MATCH_RESULT_PKGVER;
else if (MATCH_RESULT_PKGVER != *match)
*match = MATCH_RESULT_ANYTHING;
break;
}
return 0;
}
/// Parses an optional output prefix from *args* and returns it.
const char*
parse_args(const int argc, char* argv[])
{
int opt;
const char* prefix = NULL;
while (NULL == prefix && -1 != (opt = getopt(argc, argv, ":d"))) {
switch (opt) {
case 'd':
prefix = "pkgrel=";
break;
default:
prefix = argv[optind - 1]; // Use first option that is not -d as a normal prefix, too.
break;
}
}
if (NULL == prefix) {
if (argc > optind)
prefix = argv[optind];
else
prefix = "";
}
return prefix;
}
int
main(int argc, char* argv[])
{
const char* prefix = parse_args(argc, argv);
FILE* file = fopen("PKGBUILD", "r");
if (NULL == file) {
dprintf(2, "PKGBUILD not found or cannot be opened\n");
exit(1);
}
fclose(file);
git_libgit2_init();
git_repository* repo = NULL;
try_git(git_repository_open_ext(&repo, NULL, GIT_REPOSITORY_OPEN_FROM_ENV, NULL), "opening repo");
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
git_diff_options diffopts = GIT_DIFF_OPTIONS_INIT;
#pragma GCC diagnostic pop
diffopts.pathspec.strings = (char*[1]){relative_path_in_current_dir(repo, "PKGBUILD")};
diffopts.pathspec.count = 1;
diffopts.flags |= GIT_DIFF_SHOW_UNTRACKED_CONTENT;
if (NULL == diffopts.pathspec.strings[0]) {
dprintf(2, "finding PKGBUILD in repo\n");
exit(1);
}
git_pathspec* pathspec = NULL;
try_git(git_pathspec_new(&pathspec, &diffopts.pathspec), "creating pathspec");
git_revwalk* walker = NULL;
try_git(git_revwalk_new(&walker, repo), "creating revwalker");
try_git(git_revwalk_push_head(walker), "finding head");
git_oid oid;
git_tree* earlier = NULL;
git_tree* later = NULL;
int relpkg = 1;
enum match_result match = MATCH_RESULT_INIT;
while (0 == git_revwalk_next(&oid, walker)) {
git_commit* commit;
try_git(git_commit_lookup(&commit, repo, &oid), "finding commit");
if (0 == git_commit_parentcount(commit))
match = MATCH_RESULT_ROOT;
if (NULL != earlier)
git_tree_free(earlier);
earlier = later;
try_git(git_commit_tree(&later, commit), "finding tree");
git_diff* diff;
if (NULL == earlier)
try_git(git_diff_tree_to_workdir_with_index(&diff, repo, later, &diffopts), "diff");
else
try_git(git_diff_tree_to_tree(&diff, repo, later, earlier, &diffopts), "diff");
if (MATCH_RESULT_INIT != match)
match = MATCH_RESULT_COMMIT;
try_git(git_diff_foreach(diff, NULL, NULL, NULL, &match_line, &match), "searching history");
git_diff_free(diff);
git_commit_free(commit);
if (MATCH_RESULT_PKGVER == match)
break;
if (MATCH_RESULT_ANYTHING == match)
relpkg++;
}
if (MATCH_RESULT_INIT == match) {
dprintf(2, "PKGBUILD not found in history\n");
exit(1);
}
else
printf("%s%d\n", prefix, relpkg);
}
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