Add Git-derived version reporting

CMakeLists.txt

@@ -1,11 +1,34 @@
 cmake_minimum_required(VERSION 3.16)
 
-project(kindle2notes LANGUAGES CXX)
+project(kindle2notes VERSION 1.0 LANGUAGES CXX)
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
+set(KINDLE2NOTES_VERSION "${PROJECT_VERSION}")
+find_package(Git QUIET)
+if(Git_FOUND)
+  execute_process(
+    COMMAND ${GIT_EXECUTABLE} describe --tags --long --dirty --always
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+    RESULT_VARIABLE KINDLE2NOTES_GIT_RESULT
+    OUTPUT_VARIABLE KINDLE2NOTES_GIT_DESCRIBE
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+    ERROR_QUIET
+  )
+
+  if(KINDLE2NOTES_GIT_RESULT EQUAL 0 AND NOT KINDLE2NOTES_GIT_DESCRIBE STREQUAL "")
+    if(KINDLE2NOTES_GIT_DESCRIBE MATCHES "^(.+)-0-g[0-9a-f]+$")
+      set(KINDLE2NOTES_VERSION "${CMAKE_MATCH_1}")
+    else()
+      set(KINDLE2NOTES_VERSION "${KINDLE2NOTES_GIT_DESCRIBE}")
+    endif()
+  endif()
+endif()
+
+message(STATUS "kindle2notes version: ${KINDLE2NOTES_VERSION}")
+
 function(kindle2notes_enable_warnings target)
   if(MSVC)
     target_compile_options(${target} PRIVATE /W4)
@@ -29,3 +52,6 @@ add_executable(kindle2notes
   typefactory/typefactory.h
 )
 kindle2notes_enable_warnings(kindle2notes)
+target_compile_definitions(kindle2notes PRIVATE
+  KINDLE2NOTES_VERSION="${KINDLE2NOTES_VERSION}"
+)

README.md

@@ -131,6 +131,12 @@ The resulting executable is:
 build/kindle2notes
 ```
 
+When the source is built from Git, CMake obtains the version from
+`git describe`. A build made exactly from a release tag reports only that tag
+(for example, `1.0`). Later commits include their distance from the tag and
+the abbreviated commit hash (for example, `1.0-3-gabc1234`). A modified
+working tree also receives the `-dirty` suffix.
+
 ## Usage
 
 Generate LaTeX:
@@ -175,11 +181,18 @@ Short options are also available:
 ./build/kindle2notes -i input.txt -o notes.md -t md
 ```
 
+Show the version compiled into the executable:
+
+```bash
+./build/kindle2notes --version
+```
+
 | Argument | Short form | Description |
 | --- | --- | --- |
 | `--input` | `-i` | Path to the Kindle clippings file |
 | `--output` | `-o` | Path to the generated file |
 | `--type` | `-t` | Output format: `latex`, `md`, `org`, or `adoc` |
+| `--version` | `-v` | Show the compiled version and exit |
 | `--help` | `-h` | Show usage information |
 
 If an unsupported output type is requested, the program prints the list of

typefactory/main.cpp

@@ -9,6 +9,10 @@
 #include "convertorg.h"
 #include "typefactory.h"
 
+#ifndef KINDLE2NOTES_VERSION
+#define KINDLE2NOTES_VERSION "unknown"
+#endif
+
 using ConverterFactory = TypeFactory<std::string, Converter, std::string>;
 
 static constexpr std::array<const char *, 4> kSupportedTypes = {
@@ -19,11 +23,13 @@ struct CliArgs {
   std::string input;
   std::string output;
   std::string type;
+  bool version = false;
 };
 
 static void print_usage (const char *argv0) {
   std::cerr << "Usage: " << argv0
-            << " --input <file> --output <file> --type <type>\n";
+            << " --input <file> --output <file> --type <type>\n"
+            << "       " << argv0 << " --version\n";
 }
 
 static void print_supported_types() {
@@ -47,12 +53,13 @@ static bool parse_args (int argc, char **argv, CliArgs &out) {
     {"input",  required_argument, nullptr, 'i'},
     {"output", required_argument, nullptr, 'o'},
     {"type",   required_argument, nullptr, 't'},
+    {"version", no_argument,      nullptr, 'v'},
     {"help",   no_argument,       nullptr, 'h'},
     {nullptr,  0,                 nullptr,  0 }
   };
 
   int c = 0;
-  while ((c = ::getopt_long (argc, argv, "i:o:t:h", long_opts, nullptr)) != -1) {
+  while ((c = ::getopt_long (argc, argv, "i:o:t:vh", long_opts, nullptr)) != -1) {
     switch (c) {
       case 'i':
         out.input = optarg;
@@ -63,6 +70,9 @@ static bool parse_args (int argc, char **argv, CliArgs &out) {
       case 't':
         out.type = optarg;
         break;
+      case 'v':
+        out.version = true;
+        break;
       case 'h':
         print_usage (argv[0]);
         return false;
@@ -72,7 +82,8 @@ static bool parse_args (int argc, char **argv, CliArgs &out) {
     }
   }
 
-  if (out.input.empty() || out.output.empty() || out.type.empty()) {
+  if (!out.version &&
+      (out.input.empty() || out.output.empty() || out.type.empty())) {
     print_usage (argv[0]);
     return false;
   }
@@ -85,6 +96,11 @@ int main (int argc, char **argv) {
   if (!parse_args (argc, argv, args))
     return 1;
 
+  if (args.version) {
+    std::cout << "kindle2notes " << KINDLE2NOTES_VERSION << '\n';
+    return 0;
+  }
+
   const ConverterFactory factory = build_converter_factory();
   if (!factory.contains (args.type)) {
     std::cerr << "Unsupported output type: " << args.type << '\n';