Ignore switches following "--" when parsing a command line.

BUG=933004
R=wfh@chromium.org

Change-Id: I911be4cbfc38a4d41dec85d85f7fe0f50ddca392
Reviewed-on: https://chromium-review.googlesource.com/c/1481210
Auto-Submit: Greg Thompson <grt@chromium.org>
Commit-Queue: Julian Pastarmov <pastarmovj@chromium.org>
Reviewed-by: Julian Pastarmov <pastarmovj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634604}

chrome/install_static/install_util.cc

@@ -847,13 +847,15 @@ std::vector<std::wstring> TokenizeCommandLineToArray(
 
 std::wstring GetSwitchValueFromCommandLine(const std::wstring& command_line,
                                            const std::wstring& switch_name) {
+  static constexpr wchar_t kSwitchTerminator[] = L"--";
   assert(!command_line.empty());
   assert(!switch_name.empty());
 
   std::vector<std::wstring> as_array = TokenizeCommandLineToArray(command_line);
   std::wstring switch_with_equal = L"--" + switch_name + L"=";
-  for (size_t i = 1; i < as_array.size(); ++i) {
-    const std::wstring& arg = as_array[i];
+  auto end = std::find(as_array.cbegin(), as_array.cend(), kSwitchTerminator);
+  for (auto scan = as_array.cbegin(); scan != end; ++scan) {
+    const std::wstring& arg = *scan;
     if (arg.compare(0, switch_with_equal.size(), switch_with_equal) == 0)
       return arg.substr(switch_with_equal.size());
   }

chrome/install_static/install_util.h

@@ -275,9 +275,10 @@ std::vector<std::wstring> TokenizeString16(const std::wstring& str,
 std::vector<std::wstring> TokenizeCommandLineToArray(
     const std::wstring& command_line);
 
-// We assume that the command line |command_line| contains multiple switches
-// with the format --<switch name>=<switch value>. This function returns the
-// value of the |switch_name| passed in.
+// Returns the value of a switch of the form "--<switch name>=<switch value>" in
+// |command_line|. An empty switch in |command_line| ("--") denotes the end of
+// switches and the beginning of args. Anything of the form --<switch
+// name>=<switch value> following "--" is ignored.
 std::wstring GetSwitchValueFromCommandLine(const std::wstring& command_line,
                                            const std::wstring& switch_name);
 

chrome/install_static/install_util_unittest.cc

@@ -96,6 +96,10 @@ TEST(InstallStaticTest, GetSwitchValueFromCommandLineTest) {
   // Bad command line without closing quotes. Should not crash.
   value = GetSwitchValueFromCommandLine(L"\"blah --type=\t\t\t", L"type");
   EXPECT_TRUE(value.empty());
+
+  // Anything following "--" should be considered args and therfore ignored.
+  value = GetSwitchValueFromCommandLine(L"blah -- --type=bleh", L"type");
+  EXPECT_TRUE(value.empty());
 }
 
 TEST(InstallStaticTest, SpacesAndQuotesInCommandLineArguments) {