Fix JRUBY-6620: On windows if JAVA_HOME ends in a '\' then native launcher bombs

Before processing JAVA_HOME, trim the trailing backslashes, which could
cause problems.

Author: BanzaiMan

platformlauncher.cpp

@@ -220,6 +220,7 @@ bool PlatformLauncher::checkJDKHome() {
         logMsg("-Xjdkhome is not set, checking for %%JAVA_HOME%%...");
         char *javaHome = getenv("JAVA_HOME");
         if (javaHome) {
+            javaHome = trimTrailingBackslashes(javaHome);
             logMsg("%%JAVA_HOME%% is set: %s", javaHome);
             if (!jvmLauncher.initialize(javaHome)) {
                 logMsg("ERROR: Cannot locate java installation, specified by JAVA_HOME: %s", javaHome);

spec/launcher_spec.rb

@@ -49,6 +49,16 @@
     end
   end
 
+  it "should drop the backslashes at the end of JAVA_HOME" do
+    with_environment "JAVA_HOME" => File.join("some", "java", "home\\\\") do
+      if windows?
+        jruby_launcher_args("").join.should =~ %r{some/java/home}
+      else
+        jruby_launcher_args("").first.should == File.join("some", "java", "home", "bin", "java")
+      end
+    end
+  end
+
   it "should complain about a missing log argument" do
     jruby_launcher("-Xtrace 2>&1").should =~ /Argument is missing for "-Xtrace"/
     jruby_launcher("-Xtrace -- 2>&1").should =~ /Argument is missing for "-Xtrace"/

unixlauncher.cpp

@@ -52,7 +52,9 @@ int UnixLauncher::run(int argc, char* argv[], char* envp[]) {
         if (!jdkhome.empty()) {
             java = jdkhome + "/bin/java";
         } else if (getenv("JAVA_HOME") != NULL) {
-            java = string(getenv("JAVA_HOME")) + "/bin/java";
+            string java_home = string(getenv("JAVA_HOME"));
+            java_home = trimTrailingBackslashes(java_home);
+            java = java_home + "/bin/java";
         } else {
             java = findOnPath("java");
         }

utilsfuncs.cpp

@@ -269,3 +269,11 @@ void printListToConsole(list<string> values) {
         std::cout << *it << std::endl;
     }
 }
+
+string trimTrailingBackslashes(string orig) {
+    while (orig.size() > 0 &&
+        orig.at(orig.size() - 1) == '\\') {
+        orig.erase(orig.size() - 1);
+    }
+    return orig;
+}

utilsfuncs.h

@@ -59,6 +59,7 @@ void addToArgList(std::list<std::string> & args, int argc, char ** argv);
 std::string findOnPath(const char* name);
 bool checkDirectory(const char* path);
 void printListToConsole(std::list<std::string> l);
+std::string trimTrailingBackslashes(std::string orig);
 
 #ifndef WIN32
 #define FILE_SEP '/'