1 files changed, 242 insertions, 0 deletions
diff --git a/gitstatus/src/git.cc b/gitstatus/src/git.cc
new file mode 100644
index 00000000..029b02bf
--- /dev/null
+++ b/gitstatus/src/git.cc
@@ -0,0 +1,242 @@
+// Copyright 2019 Roman Perepelitsa.
+//
+// This file is part of GitStatus.
+//
+// GitStatus is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// GitStatus is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with GitStatus. If not, see <https://www.gnu.org/licenses/>.
+
+#include "git.h"
+
+#include <cstdlib>
+#include <cstring>
+#include <fstream>
+#include <sstream>
+#include <utility>
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "arena.h"
+#include "check.h"
+#include "print.h"
+#include "scope_guard.h"
+
+namespace gitstatus {
+
+const char* GitError() {
+  const git_error* err = git_error_last();
+  return err && err->message ? err->message : "unknown error";
+}
+
+std::string RepoState(git_repository* repo) {
+  Arena arena;
+  StringView gitdir(git_repository_path(repo));
+
+  // These names mostly match gitaction in vcs_info:
+  // https://github.com/zsh-users/zsh/blob/master/Functions/VCS_Info/Backends/VCS_INFO_get_data_git.
+  auto State = [&]() {
+    switch (git_repository_state(repo)) {
+      case GIT_REPOSITORY_STATE_NONE:
+        return "";
+      case GIT_REPOSITORY_STATE_MERGE:
+        return "merge";
+      case GIT_REPOSITORY_STATE_REVERT:
+        return "revert";
+      case GIT_REPOSITORY_STATE_REVERT_SEQUENCE:
+        return "revert-seq";
+      case GIT_REPOSITORY_STATE_CHERRYPICK:
+        return "cherry";
+      case GIT_REPOSITORY_STATE_CHERRYPICK_SEQUENCE:
+        return "cherry-seq";
+      case GIT_REPOSITORY_STATE_BISECT:
+        return "bisect";
+      case GIT_REPOSITORY_STATE_REBASE:
+        return "rebase";
+      case GIT_REPOSITORY_STATE_REBASE_INTERACTIVE:
+        return "rebase-i";
+      case GIT_REPOSITORY_STATE_REBASE_MERGE:
+        return "rebase-m";
+      case GIT_REPOSITORY_STATE_APPLY_MAILBOX:
+        return "am";
+      case GIT_REPOSITORY_STATE_APPLY_MAILBOX_OR_REBASE:
+        return "am/rebase";
+    }
+    return "action";
+  };
+
+  auto DirExists = [&](StringView name) {
+    int fd = open(arena.StrCat(gitdir, "/", name), O_DIRECTORY | O_CLOEXEC);
+    if (fd < 0) return false;
+    CHECK(!close(fd)) << Errno();
+    return true;
+  };
+
+  auto ReadFile = [&](StringView name) {
+    std::ifstream strm(arena.StrCat(gitdir, "/", name));
+    std::string res;
+    strm >> res;
+    return res;
+  };
+
+  std::string next;
+  std::string last;
+
+  if (DirExists("rebase-merge")) {
+    next = ReadFile("rebase-merge/msgnum");
+    last = ReadFile("rebase-merge/end");
+  } else if (DirExists("rebase-apply")) {
+    next = ReadFile("rebase-apply/next");
+    last = ReadFile("rebase-apply/last");
+  }
+
+  std::ostringstream res;
+  res << State();
+  if (!next.empty() && !last.empty()) res << ' ' << next << '/' << last;
+  return res.str();
+}
+
+size_t CountRange(git_repository* repo, const std::string& range) {
+  git_revwalk* walk = nullptr;
+  VERIFY(!git_revwalk_new(&walk, repo)) << GitError();
+  ON_SCOPE_EXIT(=) { git_revwalk_free(walk); };
+  VERIFY(!git_revwalk_push_range(walk, range.c_str())) << GitError();
+  size_t res = 0;
+  while (true) {
+    git_oid oid;
+    switch (git_revwalk_next(&oid, walk)) {
+      case 0:
+        ++res;
+        break;
+      case GIT_ITEROVER:
+        return res;
+      default:
+        LOG(ERROR) << "git_revwalk_next: " << range << ": " << GitError();
+        throw Exception();
+    }
+  }
+}
+
+size_t NumStashes(git_repository* repo) {
+  size_t res = 0;
+  auto* cb = +[](size_t index, const char* message, const git_oid* stash_id, void* payload) {
+    ++*static_cast<size_t*>(payload);
+    return 0;
+  };
+  if (!git_stash_foreach(repo, cb, &res)) return res;
+  // Example error: failed to parse signature - malformed e-mail.
+  // See https://github.com/romkatv/powerlevel10k/issues/216.
+  LOG(WARN) << "git_stash_foreach: " << GitError();
+  return 0;
+}
+
+git_reference* Head(git_repository* repo) {
+  git_reference* symbolic = nullptr;
+  switch (git_reference_lookup(&symbolic, repo, "HEAD")) {
+    case 0:
+      break;
+    case GIT_ENOTFOUND:
+      return nullptr;
+    default:
+      LOG(ERROR) << "git_reference_lookup: " << GitError();
+      throw Exception();
+  }
+
+  git_reference* direct = nullptr;
+  if (git_reference_resolve(&direct, symbolic)) {
+    LOG(INFO) << "Empty git repo (no HEAD)";
+    return symbolic;
+  }
+  git_reference_free(symbolic);
+  return direct;
+}
+
+const char* LocalBranchName(const git_reference* ref) {
+  CHECK(ref);
+  git_reference_t type = git_reference_type(ref);
+  switch (type) {
+    case GIT_REFERENCE_DIRECT: {
+      return git_reference_is_branch(ref) ? git_reference_shorthand(ref) : "";
+    }
+    case GIT_REFERENCE_SYMBOLIC: {
+      static constexpr char kHeadPrefix[] = "refs/heads/";
+      const char* target = git_reference_symbolic_target(ref);
+      if (!target) return "";
+      size_t len = std::strlen(target);
+      if (len < sizeof(kHeadPrefix)) return "";
+      if (std::memcmp(target, kHeadPrefix, sizeof(kHeadPrefix) - 1)) return "";
+      return target + (sizeof(kHeadPrefix) - 1);
+    }
+    case GIT_REFERENCE_INVALID:
+    case GIT_REFERENCE_ALL:
+      break;
+  }
+  LOG(ERROR) << "Invalid reference type: " << type;
+  throw Exception();
+}
+
+RemotePtr GetRemote(git_repository* repo, const git_reference* local) {
+  git_remote* remote;
+  git_buf symref = {};
+  if (git_branch_remote(&remote, &symref, repo, git_reference_name(local))) return nullptr;
+  ON_SCOPE_EXIT(&) {
+    git_remote_free(remote);
+    git_buf_free(&symref);
+  };
+
+  git_reference* ref;
+  if (git_reference_lookup(&ref, repo, symref.ptr)) return nullptr;
+  ON_SCOPE_EXIT(&) { if (ref) git_reference_free(ref); };
+
+  const char* branch = nullptr;
+  std::string name = remote ? git_remote_name(remote) : ".";
+  if (git_branch_name(&branch, ref)) {
+    branch = "";
+  } else if (remote) {
+    VERIFY(std::strstr(branch, name.c_str()) == branch);
+    VERIFY(branch[name.size()] == '/');
+    branch += name.size() + 1;
+  }
+
+  auto res = std::make_unique<Remote>();
+  res->name = std::move(name);
+  res->branch = branch;
+  res->url = remote ? (git_remote_url(remote) ?: "") : "";
+  res->ref = std::exchange(ref, nullptr);
+  return RemotePtr(res.release());
+}
+
+PushRemotePtr GetPushRemote(git_repository* repo, const git_reference* local) {
+  git_remote* remote;
+  git_buf symref = {};
+  if (git_branch_push_remote(&remote, &symref, repo, git_reference_name(local))) return nullptr;
+  ON_SCOPE_EXIT(&) {
+    git_remote_free(remote);
+    git_buf_free(&symref);
+  };
+
+  git_reference* ref;
+  if (git_reference_lookup(&ref, repo, symref.ptr)) return nullptr;
+  ON_SCOPE_EXIT(&) { if (ref) git_reference_free(ref); };
+
+  std::string name = remote ? git_remote_name(remote) : ".";
+
+  auto res = std::make_unique<PushRemote>();
+  res->name = std::move(name);
+  res->url = remote ? (git_remote_url(remote) ?: "") : "";
+  res->ref = std::exchange(ref, nullptr);
+  return PushRemotePtr(res.release());
+}
+
+}  // namespace gitstatus