Git prompt using libgit2 (again)

custom-prompt/.clang-format

@@ -54,7 +54,7 @@ BreakBeforeInheritanceComma: false
 BreakInheritanceList: BeforeColon
 BreakBeforeTernaryOperators: true
 BreakConstructorInitializersBeforeComma: false
-BreakConstructorInitializers: BeforeComma
+BreakConstructorInitializers: AfterColon
 BreakAfterJavaFieldAnnotations: false
 BreakStringLiterals: true
 ColumnLimit:     119

custom-prompt/Makefile

@@ -1,7 +1,8 @@
 CC = gcc
+CPPFLAGS = $(shell pkg-config --cflags libgit2)
 CFLAGS = -fstrict-aliasing -std=c11 -Wall -Wextra
 CXXFLAGS = -fstrict-aliasing -std=c++17 -Wall -Wextra
-LDLIBS = -lstdc++
+LDLIBS = -lstdc++ $(shell pkg-config --libs libgit2)
 
 MainSource = custom-prompt.cc
 MainBashObject = custom-bash-prompt.o

custom-prompt/custom-prompt.cc

@@ -3,17 +3,20 @@
 #include <cstddef>
 #include <cstdio>
 #include <cstdlib>
+#include <filesystem>
+#include <fstream>
 #include <iomanip>
 #include <iostream>
 #include <sstream>
 #include <string>
 
-#ifdef __linux__
 namespace C
 {
+#include <git2.h>
+#ifdef __linux__
 #include <libnotify/notify.h>
-}
 #endif
+}
 
 #if defined __APPLE__
 #define HOST_ICON ""
@@ -163,6 +166,99 @@ void Interval::print_long(std::ostream& ostream) const
  *****************************************************************************/
 extern "C" long long unsigned get_active_wid(void);
 
+/******************************************************************************
+ * Store information about the current Git repository.
+ *****************************************************************************/
+class GitRepository
+{
+private:
+    C::git_repository* repo;
+    std::filesystem::path gitdir;
+    std::string ref;
+    bool detached;
+    bool bisecting, cherrypicking, merging, rebasing, reverting;
+
+public:
+    GitRepository(void);
+    std::string reference(void);
+    std::string info(void);
+};
+
+/******************************************************************************
+ * Read the current Git repository.
+ *****************************************************************************/
+GitRepository::GitRepository(void) :
+    bisecting(false), cherrypicking(false), merging(false), rebasing(false), reverting(false)
+{
+    C::git_libgit2_init();
+    if (C::git_repository_open_ext(&this->repo, ".", 0, nullptr) != 0)
+    {
+        return;
+    }
+    this->gitdir = C::git_repository_path(this->repo);
+    this->ref = this->reference();
+    this->detached = C::git_repository_head_detached(this->repo);
+    switch (C::git_repository_state(this->repo))
+    {
+    case C::GIT_REPOSITORY_STATE_BISECT:
+        this->bisecting = true;
+        break;
+    case C::GIT_REPOSITORY_STATE_CHERRYPICK:
+    case C::GIT_REPOSITORY_STATE_CHERRYPICK_SEQUENCE:
+        this->cherrypicking = true;
+        break;
+    case C::GIT_REPOSITORY_STATE_MERGE:
+        this->merging = true;
+        break;
+    case C::GIT_REPOSITORY_STATE_REBASE:
+    case C::GIT_REPOSITORY_STATE_REBASE_INTERACTIVE:
+    case C::GIT_REPOSITORY_STATE_REBASE_MERGE:
+        this->rebasing = true;
+        break;
+    case C::GIT_REPOSITORY_STATE_REVERT:
+    case C::GIT_REPOSITORY_STATE_REVERT_SEQUENCE:
+        this->reverting = true;
+        break;
+    }
+}
+
+/******************************************************************************
+ * Read the reference of the current Git repository.
+ *
+ * @return Git reference (branch name or commit hash).
+ *****************************************************************************/
+std::string GitRepository::reference(void)
+{
+    // The head is not resolved correctly if there are no commits yet, so just
+    // do this manually.
+    std::ifstream head_file(this->gitdir / "HEAD");
+    std::string head_contents;
+    std::getline(head_file, head_contents);
+    if (head_contents.rfind("ref: refs/heads/", 0) == 0)
+    {
+        return head_contents.substr(16);
+    }
+    return head_contents.substr(0, 8);
+}
+
+/******************************************************************************
+ * Provide information about the current Git repository in a manner suitable to
+ * display in the shell prompt.
+ *
+ * @return Git information.
+ *****************************************************************************/
+std::string GitRepository::info(void)
+{
+    LOG_DEBUG("ref=%s", this->ref.data());
+    LOG_DEBUG("detached=%d", this->detached);
+    LOG_DEBUG("bisecting=%d", this->bisecting);
+    LOG_DEBUG("cherrypicking=%d", this->cherrypicking);
+    LOG_DEBUG("merging=%d", this->merging);
+    LOG_DEBUG("rebasing=%d", this->rebasing);
+    LOG_DEBUG("reverting=%d", this->reverting);
+    return "";
+}
+
 /******************************************************************************
  * Get the current timestamp.
  *
@@ -384,6 +480,7 @@ int main_internal(int const argc, char const* argv[])
     std::size_t columns = std::stoull(argv[5]);
     report_command_status(last_command, exit_code, delay, prev_active_wid, columns);
 
+    GitRepository().info();
     std::string_view git_info(argv[6]);
     int shlvl = std::stoi(argv[7]);
     display_primary_prompt(git_info, shlvl);