PoB Process count

The new `GetProcessCount` helper (sys_main.cpp:438) walks the system process list via Windows’ Toolhelp API—no external commands. It creates a snapshot with `CreateToolhelp32Snapshot`, iterates `PROCESSENTRY32W`, lowercases each executable name, and increments a counter whenever the name matches one of the PoB executable variants passed in from Lua. That count flows back through the Lua binding (ui_api.cpp:2024) up to `getMatchingProcessCount` in src/Launch.lua:20, so the updater knows exactly how many sibling PoB processes are running.

Author: LocalIdentity

engine/system/sys_main.h

@@ -7,6 +7,7 @@
 #include <filesystem>
 #include <optional>
 #include <string>
+#include <vector>
 
 // =======
 // Classes
@@ -78,6 +79,7 @@ class sys_IMain {
 	virtual char*	ClipboardPaste() = 0;
 	virtual bool	SetWorkDir(std::filesystem::path const& newCwd = {}) = 0;
 	virtual void	SpawnProcess(std::filesystem::path cmdName, const char* argList) = 0;
+	virtual int		GetProcessCount(const std::vector<std::wstring>& imageNames) = 0;
 	virtual std::optional<std::string> OpenURL(const char* url) = 0;
 	virtual void	Error(const char* fmt, ...) = 0;
 	virtual void	Exit(const char* msg = NULL) = 0;

engine/system/win/sys_local.h

@@ -37,6 +37,7 @@ class sys_main_c: public sys_IMain {
 	char*	ClipboardPaste();
 	bool	SetWorkDir(std::filesystem::path const& newCwd = {});
 	void	SpawnProcess(std::filesystem::path cmdName, const char* argList);
+	int		GetProcessCount(const std::vector<std::wstring>& imageNames);
 	std::optional<std::string> OpenURL(const char* url); // return value has failure reason
 	void	Error(const char* fmt, ...);
 	void	Exit(const char* msg = NULL);

engine/system/win/sys_main.cpp

@@ -15,6 +15,7 @@
 #ifdef _WIN32
 #include <eh.h>
 #include <Shlobj.h>
+#include <TlHelp32.h>
 #elif __linux__
 #include <unistd.h>
 #include <limits.h>
@@ -35,6 +36,9 @@
 #include <thread>
 
 #include <fmt/core.h>
+#include <algorithm>
+#include <cwctype>
+#include <unordered_set>
 
 // ======
 // Locals
@@ -434,6 +438,47 @@ void sys_main_c::SpawnProcess(std::filesystem::path cmdName, const char* argList
 #endif
 }
 
+int sys_main_c::GetProcessCount(const std::vector<std::wstring>& imageNames)
+{
+#ifdef _WIN32
+	if (imageNames.empty()) {
+		return 0;
+	}
+	std::unordered_set<std::wstring> lookup;
+	lookup.reserve(imageNames.size());
+	for (const auto& name : imageNames) {
+		std::wstring lowered = name;
+		std::transform(lowered.begin(), lowered.end(), lowered.begin(), [](wchar_t c) {
+			return std::towlower(c);
+		});
+		lookup.insert(std::move(lowered));
+	}
+	HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+	if (snapshot == INVALID_HANDLE_VALUE) {
+		return -1;
+	}
+	PROCESSENTRY32W entry{};
+	entry.dwSize = sizeof(entry);
+	int count = 0;
+	if (Process32FirstW(snapshot, &entry)) {
+		do {
+			std::wstring exe(entry.szExeFile);
+			std::transform(exe.begin(), exe.end(), exe.begin(), [](wchar_t c) {
+				return std::towlower(c);
+			});
+			if (lookup.find(exe) != lookup.end()) {
+				++count;
+			}
+		} while (Process32NextW(snapshot, &entry));
+	}
+	CloseHandle(snapshot);
+	return count;
+#else
+	(void)imageNames;
+	return -1;
+#endif
+}
+
 std::string GetWineHostVersion()
 {
 #ifdef _WIN32

ui_api.cpp

@@ -10,6 +10,7 @@
 #include <fstream>
 #include <zlib.h>
 #include <cmath>
+#include <vector>
 
 #include "core/core_tex_manipulation.h"
 
@@ -101,6 +102,7 @@
 ** ConPrintTable(table[, noRecurse])
 ** ConExecute("<cmd>")
 ** SpawnProcess("<cmdName>"[, "<args>"])
+** count = GetProcessCount({"<image1>", ...})
 ** err = OpenURL("<url>")
 ** SetProfiling(isEnabled)
 ** Restart()
@@ -2017,6 +2019,26 @@ static int l_SpawnProcess(lua_State* L)
 	return 0;
 }
 
+static int l_GetProcessCount(lua_State* L)
+{
+	ui_main_c* ui = GetUIPtr(L);
+	ui->LAssert(L, lua_gettop(L) >= 1, "Usage: GetProcessCount(names)");
+	ui->LAssert(L, lua_istable(L, 1), "GetProcessCount() argument 1: expected table, got %s", luaL_typename(L, 1));
+	std::vector<std::wstring> names;
+	size_t len = lua_rawlen(L, 1);
+	names.reserve(len);
+	for (size_t i = 1; i <= len; ++i) {
+		lua_rawgeti(L, 1, static_cast<int>(i));
+		ui->LAssert(L, lua_isstring(L, -1), "GetProcessCount() table values must be strings, got %s", luaL_typename(L, -1));
+		auto name = lua_tostring(L, -1);
+		names.emplace_back(std::filesystem::u8path(name).wstring());
+		lua_pop(L, 1);
+	}
+	int count = ui->sys->GetProcessCount(names);
+	lua_pushinteger(L, count);
+	return 1;
+}
+
 static int l_OpenURL(lua_State* L)
 {
 	ui_main_c* ui = GetUIPtr(L);
@@ -2249,6 +2271,7 @@ int ui_main_c::InitAPI(lua_State* L)
 	ADDFUNC(ConClear);
 	ADDFUNC(print);
 	ADDFUNC(SpawnProcess);
+	ADDFUNC(GetProcessCount);
 	ADDFUNC(OpenURL);
 	ADDFUNC(SetProfiling);
 	ADDFUNC(TakeScreenshot);