[Installer] Name only the payload programs installed in the directory (#7684)

The running-instance lookup named every process whose image path began with the
install directory, subfolders included. Installing into a folder that holds
another application in a subfolder therefore reported that application as
holding the previous version, and nothing the guard offers could clear it: the
close asks cockatrice.exe only, and the end answer refuses anything that is not
a payload program. Both answers were no-ops, so the update could only abort and
tell the user to close a program that was never touching the files.

Name only the programs the payload installs, and only when the image lies in the
install directory itself. A program below the directory that really does hold a
payload file is still named by the Restart Manager lookup, which is the lookup
for that question.

The Windows probe check now covers a payload-named program in a subfolder and a
program the payload does not install; both have to come back as nothing.

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

tests/payload_paths_test.cpp

@@ -0,0 +1,57 @@
+#include "payload_paths.h"
+
+#include <gtest/gtest.h>
+#include <string>
+
+namespace
+{
+/// The directory part of a path spelled with the same case as the install directory, which
+/// is the comparison the probe makes once both sides are folded - see isSameDirectory in
+/// restart_manager_holders.cpp. Kept as a plain string here so the shape of a path can be
+/// tested without Windows.
+bool runsFrom(const std::wstring &imagePath, const std::wstring &installDir)
+{
+    return parentDirectoryOf(imagePath) == installDir;
+}
+} // namespace
+
+TEST(PayloadPaths, SplitsAnImagePathIntoItsDirectoryAndName)
+{
+    EXPECT_EQ(fileNameOf(L"D:\\Games\\Cockatrice\\cockatrice.exe"), std::wstring(L"cockatrice.exe"));
+    EXPECT_EQ(parentDirectoryOf(L"D:\\Games\\Cockatrice\\cockatrice.exe"), std::wstring(L"D:\\Games\\Cockatrice"));
+    EXPECT_EQ(fileNameOf(L"cockatrice.exe"), std::wstring(L"cockatrice.exe"));
+    EXPECT_EQ(parentDirectoryOf(L"cockatrice.exe"), std::wstring());
+    EXPECT_EQ(parentDirectoryOf(L"D:/Games/Cockatrice/cockatrice.exe"), std::wstring(L"D:/Games/Cockatrice"));
+}
+
+TEST(PayloadPaths, OnlyAnImageInTheInstallDirectoryRunsFromIt)
+{
+    const std::wstring installDir = L"D:\\Games\\Cockatrice";
+    EXPECT_TRUE(runsFrom(L"D:\\Games\\Cockatrice\\cockatrice.exe", installDir));
+    // A folder the user keeps other applications in is not the installation, and neither is
+    // a sibling whose name merely begins with the same letters.
+    EXPECT_FALSE(runsFrom(L"D:\\Games\\Cockatrice\\old\\cockatrice.exe", installDir));
+    EXPECT_FALSE(runsFrom(L"D:\\Games\\Cockatrice-old\\cockatrice.exe", installDir));
+    EXPECT_FALSE(runsFrom(L"D:\\Games\\cockatrice.exe", installDir));
+}
+
+TEST(PayloadPaths, KnowsTheProgramsThePayloadInstalls)
+{
+    EXPECT_TRUE(isPayloadProgram(L"cockatrice.exe"));
+    EXPECT_TRUE(isPayloadProgram(L"oracle.exe"));
+    EXPECT_TRUE(isPayloadProgram(L"servatrice.exe"));
+    EXPECT_TRUE(isPayloadProgram(L"COCKATRICE.EXE"));
+    EXPECT_TRUE(isPayloadProgram(L"Servatrice.Exe"));
+}
+
+TEST(PayloadPaths, LeavesEveryOtherProgramAlone)
+{
+    // A program the user keeps in the install directory, the uninstaller, a service host and
+    // a name that only looks like a payload program are all not instances of the payload.
+    EXPECT_FALSE(isPayloadProgram(L"uninstall.exe"));
+    EXPECT_FALSE(isPayloadProgram(L"tool.exe"));
+    EXPECT_FALSE(isPayloadProgram(L"svchost.exe"));
+    EXPECT_FALSE(isPayloadProgram(L"cockatrice2.exe"));
+    EXPECT_FALSE(isPayloadProgram(L"mycockatrice.exe"));
+    EXPECT_FALSE(isPayloadProgram(L""));
+}