msi: Handle escaped double quotes in command line parsing.

dlls/msi/action.c

@@ -229,7 +229,7 @@ static int parse_prop( const WCHAR *str, WCHAR *value, int *quotes )
                 break;
             case '"':
                 state = state_quote;
-                if (in_quotes) count--;
+                if (in_quotes && p[1] != '\"') count--;
                 else count++;
                 break;
             default:
@@ -267,7 +267,7 @@ static int parse_prop( const WCHAR *str, WCHAR *value, int *quotes )
             switch (*p)
             {
             case '"':
-                if (in_quotes) count--;
+                if (in_quotes && p[1] != '\"') count--;
                 else count++;
                 break;
             case ' ':

dlls/msi/tests/install.c

@@ -6350,6 +6350,18 @@ static void test_command_line_parsing(void)
     r = MsiInstallProductA(msifile, cmd);
     ok(r == ERROR_INSTALL_FAILURE, "Expected ERROR_INSTALL_FAILURE, got %u\n", r);
 
+    cmd = "P=\"\"\"one\"\"\" Q=\"two\"";
+    r = MsiInstallProductA(msifile, cmd);
+    ok(r == ERROR_SUCCESS, "Expected ERROR_SUCCESS, got %u\n", r);
+
+    cmd = "P=\"one \"\"two\"\"\" Q=\"three\"";
+    r = MsiInstallProductA(msifile, cmd);
+    ok(r == ERROR_SUCCESS, "Expected ERROR_SUCCESS, got %u\n", r);
+
+    cmd = "P=\"\"\"one\"\" two\" Q=\"three\"";
+    r = MsiInstallProductA(msifile, cmd);
+    ok(r == ERROR_SUCCESS, "Expected ERROR_SUCCESS, got %u\n", r);
+
     DeleteFile(msifile);
     RemoveDirectory("msitest");
 }