Bug 1013917 part 2 - Add shell functions for testing latin1 strings. r=luke

js/src/jit-test/tests/basic/latin1.js

@@ -0,0 +1,5 @@
+var s = "Foo123";
+assertEq(isLatin1(s), false);
+
+s = toLatin1(s);
+assertEq(isLatin1(s), true);

js/src/shell/js.cpp

@@ -4430,6 +4430,30 @@ PrintProfilerEvents(JSContext *cx, unsigned argc, Value *vp)
     return true;
 }
 
+static bool
+IsLatin1(JSContext *cx, unsigned argc, Value *vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+    bool isLatin1 = args.get(0).isString() && args[0].toString()->hasLatin1Chars();
+    args.rval().setBoolean(isLatin1);
+    return true;
+}
+
+static bool
+ToLatin1(JSContext *cx, unsigned argc, Value *vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+    if (!args.get(0).isString() || !args[0].toString()->isLinear()) {
+        args.rval().setUndefined();
+        return true;
+    }
+
+    JSLinearString *s = &args[0].toString()->asLinear();
+    s->debugUnsafeConvertToLatin1();
+    args.rval().setString(s);
+    return true;
+}
+
 static const JSFunctionSpecWithHelp shell_functions[] = {
     JS_FN_HELP("version", Version, 0, 0,
 "version([number])",
@@ -4794,6 +4818,10 @@ static const JSFunctionSpecWithHelp shell_functions[] = {
 "  Register a callback with the profiler that prints javascript profiler events\n"
 "  to stderr.  Callback is only registered if profiling is enabled."),
 
+    JS_FN_HELP("isLatin1", IsLatin1, 1, 0,
+"isLatin1(s)",
+"  Return true iff the string's characters are stored as Latin1."),
+
     JS_FS_HELP_END
 };
 
@@ -4858,6 +4886,10 @@ static const JSFunctionSpecWithHelp fuzzing_unsafe_functions[] = {
 "untrap(fun[, pc])",
 "  Remove a trap."),
 
+    JS_FN_HELP("toLatin1", ToLatin1, 1, 0,
+"toLatin1(s)",
+"  Convert the string's characters to Latin1."),
+
     JS_FN_HELP("withSourceHook", WithSourceHook, 1, 0,
 "withSourceHook(hook, fun)",
 "  Set this JS runtime's lazy source retrieval hook (that is, the hook\n"

js/src/vm/String.cpp

@@ -116,6 +116,27 @@ JSString::equals(const char *s)
 }
 #endif /* DEBUG */
 
+void
+JSLinearString::debugUnsafeConvertToLatin1()
+{
+    // Temporary helper function to test changes for bug 998392.
+
+    MOZ_ASSERT(hasTwoByteChars());
+    MOZ_ASSERT(!hasBase());
+
+    size_t len = length();
+    const jschar *twoByteChars = chars();
+    char *latin1Chars = (char *)twoByteChars;
+
+    for (size_t i = 0; i < len; i++) {
+        MOZ_ASSERT((twoByteChars[i] & 0xff00) == 0);
+        latin1Chars[i] = char(twoByteChars[i]);
+    }
+
+    latin1Chars[len] = '\0';
+    d.u1.flags |= LATIN1_CHARS_BIT;
+}
+
 static MOZ_ALWAYS_INLINE bool
 AllocChars(ThreadSafeContext *maybecx, size_t length, jschar **chars, size_t *capacity)
 {

js/src/vm/String.h

@@ -592,6 +592,9 @@ class JSLinearString : public JSString
         JS_ASSERT(JSString::isLinear());
         return JS::TwoByteChars(chars(), length());
     }
+
+    /* Temporary, unsafe helper function for bug 998392. Don't use for anything else. */
+    void debugUnsafeConvertToLatin1();
 };
 
 JS_STATIC_ASSERT(sizeof(JSLinearString) == sizeof(JSString));