Release v0.2.1: support remote input, safe updates and high-DPI windows

src/update.cpp

@@ -0,0 +1,103 @@
+#include "update.h"
+#include "json.hpp"
+
+namespace ks
+{
+namespace
+{
+struct Handle
+{
+    HANDLE value{};
+    ~Handle() { if (value) CloseHandle(value); }
+};
+std::wstring quoteArgument(const std::wstring &value)
+{
+    // Windows argv escaping, including a path ending with a backslash.
+    std::wstring out = L"\"";
+    size_t slashes = 0;
+    for (auto ch : value)
+    {
+        if (ch == L'\\') { ++slashes; continue; }
+        out.append(ch == L'"' ? slashes * 2 + 1 : slashes, L'\\');
+        slashes = 0;
+        out += ch;
+    }
+    out.append(slashes * 2, L'\\');
+    return out + L'"';
+}
+}
+UpdateResult runUpdate(bool install, const std::wstring &expectedVersion)
+{
+    UpdateResult result;
+    GUID guid{};
+    if (FAILED(CoCreateGuid(&guid))) throw std::runtime_error("Cannot create update identifier");
+    wchar_t id[40]{};
+    StringFromGUID2(guid, id, 40);
+    auto work = std::filesystem::temp_directory_path() / (L"KSwitcher-update-" + std::wstring(id));
+    std::filesystem::create_directory(work);
+    bool detached = false;
+    Handle child;
+    try
+    {
+        HRSRC resource = FindResourceW(nullptr, MAKEINTRESOURCEW(201), RT_RCDATA);
+        HGLOBAL loaded = resource ? LoadResource(nullptr, resource) : nullptr;
+        auto bytes = loaded ? static_cast<const unsigned char *>(LockResource(loaded)) : nullptr;
+        if (!bytes) throw std::runtime_error("The updater resource is missing");
+        atomicWrite(work / L"update.ps1", Bytes(bytes, bytes + SizeofResource(nullptr, resource)));
+        std::wstring readyName = L"Local\\KSwitcher.Update.Ready." + std::wstring(id);
+        Handle ready{CreateEventW(nullptr, TRUE, FALSE, readyName.c_str())};
+        if (!ready.value) throw std::runtime_error("Cannot create updater handshake");
+        wchar_t system[MAX_PATH]{};
+        if (!GetSystemDirectoryW(system, MAX_PATH)) throw std::runtime_error("Cannot locate Windows PowerShell");
+        auto powershell = std::filesystem::path(system) / L"WindowsPowerShell/v1.0/powershell.exe";
+        std::wstring command = quoteArgument(powershell.wstring()) + L" -NoLogo -NoProfile -NonInteractive -ExecutionPolicy Bypass -File " +
+            quoteArgument((work / L"update.ps1").wstring()) + L" -Mode " + (install ? L"Install" : L"Check") +
+            L" -CurrentVersion " + quoteArgument(AppVersion) + L" -WorkDirectory " + quoteArgument(work.wstring()) +
+            L" -InstallDirectory " + quoteArgument(std::filesystem::path(executable()).parent_path().wstring()) +
+            L" -ParentProcessId " + std::to_wstring(GetCurrentProcessId()) + L" -ReadyEvent " + quoteArgument(readyName);
+        if (install) command += L" -ExpectedVersion " + quoteArgument(expectedVersion);
+        STARTUPINFOW startup{sizeof(startup)};
+        PROCESS_INFORMATION process{};
+        if (!CreateProcessW(powershell.c_str(), command.data(), nullptr, nullptr, FALSE, CREATE_NO_WINDOW,
+                            nullptr, work.c_str(), &startup, &process))
+            throw std::runtime_error("Cannot start Windows PowerShell updater");
+        child.value = process.hProcess;
+        Handle thread{process.hThread};
+        HANDLE waits[]{ready.value, child.value};
+        DWORD waited = WaitForMultipleObjects(2, waits, FALSE, 240000);
+        if (waited != WAIT_OBJECT_0 && waited != WAIT_OBJECT_0 + 1)
+        {
+            // The helper cannot replace files while this process is alive.
+            TerminateProcess(child.value, 1);
+            WaitForSingleObject(child.value, 5000);
+            throw std::runtime_error("Update preparation timed out; the installed application was not changed");
+        }
+        auto data = readFile(work / L"result.json", 64 * 1024);
+        auto json = nlohmann::json::parse(data.begin(), data.end());
+        result.state = wide(json.at("state").get<std::string>());
+        result.version = wide(json.value("version", std::string{}));
+        result.error = wide(json.value("error", std::string{}));
+        detached = install && waited == WAIT_OBJECT_0 && result.state == L"prepared";
+        if (result.state == L"prepared" && !detached)
+            throw std::runtime_error("Update helper exited before installation");
+        if (!detached) std::filesystem::remove_all(work);
+        return result;
+    }
+    catch (...)
+    {
+        if (!detached && child.value && WaitForSingleObject(child.value, 0) == WAIT_TIMEOUT)
+        {
+            TerminateProcess(child.value, 1);
+            WaitForSingleObject(child.value, 5000);
+        }
+        if (!detached) { std::error_code ignored; std::filesystem::remove_all(work, ignored); }
+        throw;
+    }
+}
+void confirmUpdatedStartup(const std::wstring &eventName)
+{
+    if (!eventName.starts_with(L"Local\\KSwitcher.Update.Started.")) return;
+    Handle event{OpenEventW(EVENT_MODIFY_STATE, FALSE, eventName.c_str())};
+    if (event.value) SetEvent(event.value);
+}
+}