Remove dependency on procxx.

Goal is to support Windows:
See #2

CMakeLists.txt

@@ -49,6 +49,7 @@ add_executable(git-tui
   src/scroller.cpp
   src/scroller.hpp
   src/process.hpp
+  src/process.cpp
   )
 
 target_include_directories(git-tui

src/diff.cpp

@@ -223,15 +223,11 @@ int main(int argc, const char** argv) {
     files.clear();
     file_menu_entries.clear();
 
-    procxx::process git("git");
-    git.add_argument("diff");
-    git.add_argument("-U" + std::to_string(hunk_size));
+    std::string command = "git diff -U" + std::to_string(hunk_size);
     for (int i = 0; i < argc; ++i)
-      git.add_argument(argv[i]);
-    git.exec();
+      command += std::string(" ") + argv[i];
 
-    std::string diff(std::istreambuf_iterator<char>(git.output()),
-                     std::istreambuf_iterator<char>());
+    std::string diff = ExecuteProcess(command);
     files = Parse(diff);
     for (const auto& file : files)
       file_menu_entries.push_back(file.right_file);

src/log.cpp

@@ -12,6 +12,7 @@
 #include <map>                      // for map, map<>::mapped_type
 #include <memory>  // for allocator, shared_ptr, __shared_ptr_access, unique_ptr, make_unique
 #include <queue>  // for queue
+#include <sstream>
 #include <string>  // for wstring, basic_string, string, getline, operator+, operator<, to_string
 #include <utility>  // for move
 #include <vector>   // for vector
@@ -28,14 +29,7 @@ using namespace ftxui;
 namespace gittui::log {
 
 std::string ResolveHead() {
-  procxx::process git("git");
-  git.add_argument("rev-list");
-  git.add_argument("HEAD");
-  git.add_argument("-1");
-  git.exec();
-  std::string line;
-  std::getline(git.output(), line);
-  return line;
+  return ExecuteProcess("git rev-list HEAD -1");
 }
 
 struct Commit {
@@ -57,14 +51,12 @@ Commit* GetCommit(std::wstring hash) {
   Commit* commit = g_commit[hash].get();
   commit->hash = hash;
 
-  procxx::process git("git");
-  git.add_argument("cat-file");
-  git.add_argument("commit");
-  git.add_argument(to_string(hash));
-  git.exec();
+  std::string data = ExecuteProcess("git cat-file commit " + to_string(hash));
+  std::stringstream ss;
+  ss << data;
 
   std::string line;
-  while (std::getline(git.output(), line)) {
+  while (std::getline(ss, line)) {
     if (line.find("tree ", 0) == 0) {
       commit->tree = to_wstring(line.substr(5));
       continue;
@@ -87,7 +79,7 @@ Commit* GetCommit(std::wstring hash) {
 
     if (line.empty()) {
       int index = -1;
-      while (std::getline(git.output(), line)) {
+      while (std::getline(ss, line)) {
         ++index;
         if (index == 0)
           commit->title = to_wstring(line);
@@ -137,15 +129,11 @@ int main(int argc, const char** argv) {
     files.clear();
     menu_files_entries.clear();
 
-    procxx::process git("git");
-    git.add_argument("diff");
-    git.add_argument("-U" + std::to_string(hunk_size));
-    git.add_argument(to_string(commit->hash) + "~..." +
-                     to_string(commit->hash));
-    git.exec();
+    std::string diff =
+        ExecuteProcess("git diff -U" + std::to_string(hunk_size) + " " +  //
+                       to_string(commit->hash) + "~..." +                 //
+                       to_string(commit->hash));
 
-    std::string diff(std::istreambuf_iterator<char>(git.output()),
-                     std::istreambuf_iterator<char>());
     files = diff::Parse(diff);
     menu_files_entries.push_back(L"description");
     for (const auto& file : files)

src/process.cpp

@@ -0,0 +1,20 @@
+#include <array>
+#include <cstdio>
+#include <iostream>
+#include <memory>
+#include <stdexcept>
+#include <string>
+
+std::string ExecuteProcess(std::string cmd) {
+  std::array<char, 128> buffer;
+  std::string result;
+  std::unique_ptr<FILE, decltype(&pclose)> pipe(popen(cmd.c_str(), "r"),
+                                                pclose);
+  if (!pipe) {
+    throw std::runtime_error("popen() failed!");
+  }
+  while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
+    result += buffer.data();
+  }
+  return result;
+}