From 348c31f8967087b82bbd6005dc2a140619cf1d0d Mon Sep 17 00:00:00 2001
From: Terrence Cole <terrence@mozilla.com>
Date: Fri, 16 Nov 2012 18:14:51 -0800
Subject: [PATCH] Bug 811911 - Allow UTF-8 output from the SpiderMonkey shell;
 r=Norbert

---
 js/src/shell/js.cpp | 153 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 146 insertions(+), 7 deletions(-)

diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
index fdce1e6b732..796b8f30f27 100644
--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -301,6 +301,143 @@ GetLine(FILE *file, const char * prompt)
     return NULL;
 }
 
+static size_t
+GetDeflatedUTF8StringLength(JSContext *cx, const jschar *chars,
+                            size_t nchars)
+{
+    size_t nbytes;
+    const jschar *end;
+    unsigned c, c2;
+
+    nbytes = nchars;
+    for (end = chars + nchars; chars != end; chars++) {
+        c = *chars;
+        if (c < 0x80)
+            continue;
+        if (0xD800 <= c && c <= 0xDFFF) {
+            /* nbytes sets 1 length since this is surrogate pair. */
+            if (c >= 0xDC00 || (chars + 1) == end) {
+                nbytes += 2; /* Bad Surrogate */
+                continue;
+            }
+            c2 = chars[1];
+            if (c2 < 0xDC00 || c2 > 0xDFFF) {
+                nbytes += 2; /* Bad Surrogate */
+                continue;
+            }
+            c = ((c - 0xD800) << 10) + (c2 - 0xDC00) + 0x10000;
+            nbytes--;
+            chars++;
+        }
+        c >>= 11;
+        nbytes++;
+        while (c) {
+            c >>= 5;
+            nbytes++;
+        }
+    }
+    return nbytes;
+}
+
+static bool
+PutUTF8ReplacementCharacter(char **dst, size_t *dstlenp) {
+    if (*dstlenp < 3)
+        return false;
+    *(*dst)++ = (char) 0xEF;
+    *(*dst)++ = (char) 0xBF;
+    *(*dst)++ = (char) 0xBD;
+    *dstlenp -= 3;
+    return true;
+}
+
+/*
+ * Write up to |*dstlenp| bytes into |dst|.  Writes the number of bytes used
+ * into |*dstlenp| on success.  Returns false on failure.
+ */
+static bool
+DeflateStringToUTF8Buffer(JSContext *cx, const jschar *src, size_t srclen,
+                          char *dst, size_t *dstlenp)
+{
+    size_t dstlen = *dstlenp;
+    size_t origDstlen = dstlen;
+
+    while (srclen) {
+        uint32_t v;
+        jschar c = *src++;
+        srclen--;
+        if (c >= 0xDC00 && c <= 0xDFFF) {
+            if (!PutUTF8ReplacementCharacter(&dst, &dstlen))
+                goto bufferTooSmall;
+            continue;
+        } else if (c < 0xD800 || c > 0xDBFF) {
+            v = c;
+        } else {
+            if (srclen < 1) {
+                if (!PutUTF8ReplacementCharacter(&dst, &dstlen))
+                    goto bufferTooSmall;
+                continue;
+            }
+            jschar c2 = *src;
+            if ((c2 < 0xDC00) || (c2 > 0xDFFF)) {
+                if (!PutUTF8ReplacementCharacter(&dst, &dstlen))
+                    goto bufferTooSmall;
+                continue;
+            }
+            src++;
+            srclen--;
+            v = ((c - 0xD800) << 10) + (c2 - 0xDC00) + 0x10000;
+        }
+        size_t utf8Len;
+        if (v < 0x0080) {
+            /* no encoding necessary - performance hack */
+            if (dstlen == 0)
+                goto bufferTooSmall;
+            *dst++ = (char) v;
+            utf8Len = 1;
+        } else {
+            uint8_t utf8buf[4];
+            utf8Len = js_OneUcs4ToUtf8Char(utf8buf, v);
+            if (utf8Len > dstlen)
+                goto bufferTooSmall;
+            for (size_t i = 0; i < utf8Len; i++)
+                *dst++ = (char) utf8buf[i];
+        }
+        dstlen -= utf8Len;
+    }
+    *dstlenp = (origDstlen - dstlen);
+    return true;
+
+bufferTooSmall:
+    *dstlenp = (origDstlen - dstlen);
+    JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_BUFFER_TOO_SMALL);
+    return false;
+}
+
+static char *
+JSStringToUTF8(JSContext *cx, JSString *str)
+{
+    JSLinearString *linear = str->ensureLinear(cx);
+    if (!linear)
+        return NULL;
+
+    const jschar *chars = linear->chars();
+    size_t length = linear->length();
+
+    size_t tgtlen = GetDeflatedUTF8StringLength(cx, chars, length);
+    char *utf8chars = cx->pod_malloc<char>(tgtlen + 1);
+    if (!utf8chars)
+        return NULL;
+
+    bool ok = DeflateStringToUTF8Buffer(cx, chars, length, utf8chars, &tgtlen);
+    if (!ok) {
+        JS_free(cx, utf8chars);
+        return NULL;
+    }
+
+    utf8chars[tgtlen] = 0;
+    return utf8chars;
+}
+
 /*
  * State to store as JSContext private.
  *
@@ -545,10 +682,12 @@ Process(JSContext *cx, JSObject *obj_, const char *filename, bool forceTTY)
                 str = JS_ValueToSource(cx, result);
                 ok = !!str;
                 if (ok) {
-                    JSAutoByteString bytes(cx, str);
-                    ok = !!bytes;
-                    if (ok)
-                        fprintf(gOutFile, "%s\n", bytes.ptr());
+                    char *utf8chars = JSStringToUTF8(cx, str);
+                    ok = !!utf8chars;
+                    if (ok) {
+                        fprintf(gOutFile, "%s\n", utf8chars);
+                        JS_free(cx, utf8chars);
+                    }
                 }
             }
         }
@@ -1164,7 +1303,7 @@ PutStr(JSContext *cx, unsigned argc, jsval *vp)
         str = JS_ValueToString(cx, argv[0]);
         if (!str)
             return false;
-        bytes = JS_EncodeString(cx, str);
+        bytes = JSStringToUTF8(cx, str);
         if (!bytes)
             return false;
         fputs(bytes, gOutFile);
@@ -1197,7 +1336,7 @@ PrintInternal(JSContext *cx, unsigned argc, jsval *vp, FILE *file)
         str = JS_ValueToString(cx, argv[i]);
         if (!str)
             return false;
-        bytes = JS_EncodeString(cx, str);
+        bytes = JSStringToUTF8(cx, str);
         if (!bytes)
             return false;
         fprintf(file, "%s%s", i ? " " : "", bytes);
@@ -4201,7 +4340,7 @@ Exec(JSContext *cx, unsigned argc, jsval *vp)
             ok = false;
             goto done;
         }
-        nargv[i] = JS_EncodeString(cx, str);
+        nargv[i] = JSStringToUTF8(cx, str);
         if (!nargv[i]) {
             ok = false;
             goto done;