[SYCL][E2E] Fix infinite loop bug in Config/select_device.cpp

sycl/test-e2e/Config/select_device.cpp

@@ -1,6 +1,4 @@
 // REQUIRES: gpu
-// Post-commit fails due to a bug in test, will fix in a couple of days.
-// UNSUPPORTED: gpu-intel-dg2
 // RUN: %{build} -o %t.out
 //
 // RUN: env ONEAPI_DEVICE_SELECTOR="*:gpu" %{run-unfiltered-devices} %t.out DEVICE_INFO write > %t.txt
@@ -86,92 +84,66 @@ static void addEscapeSymbolToSpecialCharacters(std::string &str) {
   }
 }
 
-static std::vector<DevDescT> getAllowListDesc(std::string allowList) {
+static std::vector<DevDescT> getAllowListDesc(std::string_view allowList) {
   if (allowList.empty())
     return {};
 
-  std::string deviceName("DeviceName:");
-  std::string driverVersion("DriverVersion:");
-  std::string platformName("PlatformName:");
-  std::string platformVersion("PlatformVersion:");
   std::vector<DevDescT> decDescs;
   decDescs.emplace_back();
 
-  size_t pos = 0;
-  while (pos < allowList.size()) {
-    if ((allowList.compare(pos, deviceName.size(), deviceName)) == 0) {
-      if ((pos = allowList.find("{{", pos)) == std::string::npos) {
-        throw std::runtime_error("Malformed device allowlist");
-      }
-      size_t start = pos + 2;
-      if ((pos = allowList.find("}}", pos)) == std::string::npos) {
-        throw std::runtime_error("Malformed device allowlist");
-      }
-      decDescs.back().devName = allowList.substr(start, pos - start);
-      pos = pos + 2;
+  auto try_parse = [&](std::string_view str) -> std::optional<std::string> {
+    // std::string_view::starts_with is C++20.
+    if (allowList.compare(0, str.size(), str) != 0)
+      return {};
 
-      if (allowList[pos] == ',') {
-        pos++;
-      }
-    }
+    allowList.remove_prefix(str.size());
 
-    else if ((allowList.compare(pos, driverVersion.size(), driverVersion)) ==
-             0) {
-      if ((pos = allowList.find("{{", pos)) == std::string::npos) {
-        throw std::runtime_error("Malformed device allowlist");
-      }
-      size_t start = pos + 2;
-      if ((pos = allowList.find("}}", pos)) == std::string::npos) {
-        throw std::runtime_error("Malformed device allowlist");
-      }
-      decDescs.back().devDriverVer = allowList.substr(start, pos - start);
-      pos = pos + 2;
+    using namespace std::string_literals;
+    auto pattern_start = allowList.find("{{");
+    if (pattern_start == std::string::npos)
+      throw std::runtime_error("Malformed "s + std::string{str} + " allowlist"s);
 
-      if (allowList[pos] == ',') {
-        pos++;
-      }
-    }
+    allowList.remove_prefix(pattern_start + 2);
+    auto pattern_end = allowList.find("}}");
+    if (pattern_end == std::string::npos)
+      throw std::runtime_error("Malformed "s + std::string{str} + " allowlist"s);
 
-    else if ((allowList.compare(pos, platformName.size(), platformName)) == 0) {
-      if ((pos = allowList.find("{{", pos)) == std::string::npos) {
-        throw std::runtime_error("Malformed platform allowlist");
-      }
-      size_t start = pos + 2;
-      if ((pos = allowList.find("}}", pos)) == std::string::npos) {
-        throw std::runtime_error("Malformed platform allowlist");
-      }
-      decDescs.back().platName = allowList.substr(start, pos - start);
-      pos = pos + 2;
-      if (allowList[pos] == ',') {
-        pos++;
-      }
-    }
+    auto result =  allowList.substr(0, pattern_end);
+    allowList.remove_prefix(pattern_end + 2);
 
-    else if ((allowList.compare(pos, platformVersion.size(),
-                                platformVersion)) == 0) {
-      if ((pos = allowList.find("{{", pos)) == std::string::npos) {
-        throw std::runtime_error("Malformed platform allowlist");
-      }
-      size_t start = pos + 2;
-      if ((pos = allowList.find("}}", pos)) == std::string::npos) {
-        throw std::runtime_error("Malformed platform allowlist");
-      }
-      decDescs.back().platVer = allowList.substr(start, pos - start);
-      pos = pos + 2;
-    }
+    if (allowList[0] == ',')
+      allowList.remove_prefix(1);
+    return {std::string{result}};
+  };
 
-    else if (allowList.find('|', pos) != std::string::npos) {
-      // FIXME: That is wrong and result in a infinite loop. We start processing
-      // the string from the start here.
-      pos = allowList.find('|') + 1;
-      while (allowList[pos] == ' ') {
-        pos++;
-      }
-      decDescs.emplace_back();
-    } else {
-      throw std::runtime_error("Malformed platform allowlist");
+  while (!allowList.empty()) {
+    if (auto pattern = try_parse("DeviceName:")) {
+      decDescs.back().devName = *pattern;
+      continue;
+    }
+    if (auto pattern = try_parse("DriverVersion:")) {
+      decDescs.back().devDriverVer = *pattern;
+      continue;
+    }
+    if (auto pattern = try_parse("PlatformName:")) {
+      decDescs.back().platName = *pattern;
+      continue;
+    }
+    if (auto pattern = try_parse("PlatformVersion:")) {
+      decDescs.back().platVer = *pattern;
+      continue;
     }
-  } // while (pos <= allowList.size())
+
+    auto next = allowList.find('|');
+    if (next == std::string::npos)
+      throw std::runtime_error("Malformed allowlist");
+    allowList.remove_prefix(next + 1);
+
+    auto non_space = allowList.find_first_not_of(" ");
+    allowList.remove_prefix(non_space);
+    decDescs.emplace_back();
+  }
+
   return decDescs;
 }