From 01e95de886413c252ee1a419ed0a7c41435847e6 Mon Sep 17 00:00:00 2001
From: Egor Tensin <Egor.Tensin@gmail.com>
Date: Sun, 18 Oct 2020 03:20:06 +0300
Subject: Process: add get_exe_path()

---
 3rdparty/winapi/utf8        |  2 +-
 include/winapi/process.hpp  |  2 ++
 src/path.cpp                |  5 ++++-
 src/process.cpp             | 26 ++++++++++++++++++++++++++
 test/unit_tests/process.cpp |  5 +++++
 5 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/3rdparty/winapi/utf8 b/3rdparty/winapi/utf8
index 8fae97c..25f39c1 160000
--- a/3rdparty/winapi/utf8
+++ b/3rdparty/winapi/utf8
@@ -1 +1 @@
-Subproject commit 8fae97c1400493c23853496d0f59a3047bdd3da6
+Subproject commit 25f39c16c2024bd7c9e03b4bc84625d0c8eed849
diff --git a/include/winapi/process.hpp b/include/winapi/process.hpp
index 469653c..5f841a0 100644
--- a/include/winapi/process.hpp
+++ b/include/winapi/process.hpp
@@ -56,6 +56,8 @@ public:
 
     int get_exit_code() const;
 
+    static std::string get_exe_path();
+
     static Resource get_resource(unsigned int id);
     static std::string get_resource_string(unsigned int id);
 
diff --git a/src/path.cpp b/src/path.cpp
index 2c2deda..3df5918 100644
--- a/src/path.cpp
+++ b/src/path.cpp
@@ -16,8 +16,11 @@ namespace winapi {
 namespace {
 
 std::wstring do_canonicalize(const std::wstring& path) {
+    BOOST_STATIC_CONSTEXPR std::size_t init_buffer_size = MAX_PATH;
+    static_assert(init_buffer_size > 0, "init_buffer_size must be positive");
+
     std::vector<wchar_t> buffer;
-    buffer.resize(MAX_PATH);
+    buffer.resize(init_buffer_size);
 
     while (true) {
         const auto nch = ::GetFullPathNameW(path.c_str(), buffer.size(), buffer.data(), NULL);
diff --git a/src/process.cpp b/src/process.cpp
index d3ce3a4..7e3a9e7 100644
--- a/src/process.cpp
+++ b/src/process.cpp
@@ -122,6 +122,32 @@ HMODULE Process::get_exe_module() {
     return module;
 }
 
+std::string Process::get_exe_path() {
+    BOOST_STATIC_CONSTEXPR std::size_t init_buffer_size = MAX_PATH;
+    static_assert(init_buffer_size > 0, "init_buffer_size must be positive");
+
+    std::vector<wchar_t> buffer;
+    buffer.resize(init_buffer_size);
+
+    while (true) {
+        SetLastError(ERROR_SUCCESS);
+
+        const auto nch = ::GetModuleFileNameW(NULL, buffer.data(), buffer.size());
+
+        if (nch == 0) {
+            throw error::windows(GetLastError(), "GetModuleFileNameW");
+        }
+
+        if (nch == buffer.size() && GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
+            buffer.resize(2 * buffer.size());
+            continue;
+        }
+
+        buffer.resize(nch);
+        return narrow(buffer);
+    }
+}
+
 std::string Process::get_resource_string(unsigned int id) {
     wchar_t* s = nullptr;
 
diff --git a/test/unit_tests/process.cpp b/test/unit_tests/process.cpp
index 1c87b27..0a6cb27 100644
--- a/test/unit_tests/process.cpp
+++ b/test/unit_tests/process.cpp
@@ -21,6 +21,11 @@ using namespace winapi::process;
 
 BOOST_AUTO_TEST_SUITE(process_tests)
 
+BOOST_AUTO_TEST_CASE(get_exe_path) {
+    const auto path = Process::get_exe_path();
+    BOOST_TEST_MESSAGE("Executable path: " << path);
+}
+
 BOOST_FIXTURE_TEST_CASE(echo, WithEchoExe) {
     const CommandLine cmd_line{get_echo_exe(), {"1", "2", "3"}};
     const auto process = Process::create(cmd_line);
-- 
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