Implement RegExp serialization (#153)

JS_WriteObject() and JS_ReadObject() now support RegExp objects.

Author: bnoordhuis

cutils.h

@@ -230,6 +230,14 @@ static inline uint64_t bswap64(uint64_t v)
         ((v & ((uint64_t)0xff << (0 * 8))) << (7 * 8));
 }
 
+static inline void inplace_bswap16(uint8_t *tab) {
+    put_u16(tab, bswap16(get_u16(tab)));
+}
+
+static inline void inplace_bswap32(uint8_t *tab) {
+    put_u32(tab, bswap32(get_u32(tab)));
+}
+
 /* XXX: should take an extra argument to pass slack information to the caller */
 typedef void *DynBufReallocFunc(void *opaque, void *ptr, size_t size);
 

libregexp.c

@@ -2557,6 +2557,71 @@ const char *lre_get_groupnames(const uint8_t *bc_buf)
     return (const char *)(bc_buf + 7 + re_bytecode_len);
 }
 
+void lre_byte_swap(uint8_t *buf, size_t len, BOOL is_byte_swapped)
+{
+    uint8_t *p, *pe;
+    uint32_t n, r;
+
+    p = buf;
+    if (len < RE_HEADER_LEN)
+        abort();
+
+    // format is:
+    //  <header>
+    //  <bytecode>
+    //  <capture group name 1>
+    //  <capture group name 2>
+    //  etc.
+    n = get_u32(&p[3]); // bytecode size
+    inplace_bswap32(&p[3]);
+    if (is_byte_swapped)
+        n = bswap32(n);
+    if (n > len - RE_HEADER_LEN)
+        abort();
+
+    p = &buf[RE_HEADER_LEN];
+    pe = &p[n];
+
+    while (p < pe) {
+        n = reopcode_info[*p].size;
+        switch (n) {
+        case 1:
+        case 2:
+            break;
+        case 3:
+            switch (*p) {
+            case REOP_save_reset: // has two 8 bit arguments
+                break;
+            case REOP_range32: // variable length
+                for (r = 3 + 4 * get_u16(&p[1]); n < r; n += 4)
+                    inplace_bswap32(&p[n]);
+                goto doswap16;
+            case REOP_range: // variable length
+                for (r = 3 + 2 * get_u16(&p[1]); n < r; n += 2)
+                    inplace_bswap16(&p[n]);
+                goto doswap16;
+            default:
+            doswap16:
+                inplace_bswap16(&p[1]);
+            }
+            break;
+        case 5:
+            inplace_bswap32(&p[1]);
+            break;
+        case 17:
+            assert(*p == REOP_simple_greedy_quant);
+            inplace_bswap32(&p[1]);
+            inplace_bswap32(&p[5]);
+            inplace_bswap32(&p[9]);
+            inplace_bswap32(&p[13]);
+            break;
+        default:
+            abort();
+        }
+        p = &p[n];
+    }
+}
+
 #ifdef TEST
 
 BOOL lre_check_stack_overflow(void *opaque, size_t alloca_size)

libregexp.h

@@ -53,6 +53,8 @@ int lre_exec(uint8_t **capture,
 int lre_parse_escape(const uint8_t **pp, int allow_utf16);
 LRE_BOOL lre_is_space(int c);
 
+void lre_byte_swap(uint8_t *buf, size_t len, BOOL is_byte_swapped);
+
 /* must be provided by the user */
 LRE_BOOL lre_check_stack_overflow(void *opaque, size_t alloca_size);
 void *lre_realloc(void *opaque, void *ptr, size_t size);

quickjs.c

@@ -31659,6 +31659,7 @@ typedef enum BCTagEnum {
     BC_TAG_TYPED_ARRAY,
     BC_TAG_ARRAY_BUFFER,
     BC_TAG_SHARED_ARRAY_BUFFER,
+    BC_TAG_REGEXP,
     BC_TAG_DATE,
     BC_TAG_OBJECT_VALUE,
     BC_TAG_OBJECT_REFERENCE,
@@ -32272,6 +32273,24 @@ static int JS_WriteSharedArrayBuffer(BCWriterState *s, JSValueConst obj)
     return 0;
 }
 
+static int JS_WriteRegExp(BCWriterState *s, JSRegExp regexp)
+{
+    JSString *bc = regexp.bytecode;
+    assert(!bc->is_wide_char);
+
+    JS_WriteString(s, regexp.pattern);
+
+    if (is_be())
+        lre_byte_swap(bc->u.str8, bc->len, /*is_byte_swapped*/FALSE);
+
+    JS_WriteString(s, bc);
+
+    if (is_be())
+        lre_byte_swap(bc->u.str8, bc->len, /*is_byte_swapped*/TRUE);
+
+    return 0;
+}
+
 static int JS_WriteObjectRec(BCWriterState *s, JSValueConst obj)
 {
     uint32_t tag;
@@ -32360,6 +32379,10 @@ static int JS_WriteObjectRec(BCWriterState *s, JSValueConst obj)
                     goto invalid_tag;
                 ret = JS_WriteSharedArrayBuffer(s, obj);
                 break;
+            case JS_CLASS_REGEXP:
+                bc_put_u8(s, BC_TAG_REGEXP);
+                ret = JS_WriteRegExp(s, p->u.regexp);
+                break;
             case JS_CLASS_DATE:
                 bc_put_u8(s, BC_TAG_DATE);
                 ret = JS_WriteObjectRec(s, p->u.object_data);
@@ -33357,6 +33380,31 @@ static JSValue JS_ReadSharedArrayBuffer(BCReaderState *s)
     return JS_EXCEPTION;
 }
 
+static JSValue JS_ReadRegExp(BCReaderState *s)
+{
+    JSContext *ctx = s->ctx;
+    JSString *pattern;
+    JSString *bc;
+
+    pattern = JS_ReadString(s);
+    if (!pattern)
+        return JS_EXCEPTION;
+
+    bc = JS_ReadString(s);
+    if (!bc) {
+        js_free_string(ctx->rt, pattern);
+        return JS_EXCEPTION;
+    }
+
+    assert(!bc->is_wide_char);
+    if (is_be())
+        lre_byte_swap(bc->u.str8, bc->len, /*is_byte_swapped*/TRUE);
+
+    return js_regexp_constructor_internal(ctx, JS_UNDEFINED,
+                                          JS_MKPTR(JS_TAG_STRING, pattern),
+                                          JS_MKPTR(JS_TAG_STRING, bc));
+}
+
 static JSValue JS_ReadDate(BCReaderState *s)
 {
     JSContext *ctx = s->ctx;
@@ -33484,6 +33532,9 @@ static JSValue JS_ReadObjectRec(BCReaderState *s)
             goto invalid_tag;
         obj = JS_ReadSharedArrayBuffer(s);
         break;
+    case BC_TAG_REGEXP:
+        obj = JS_ReadRegExp(s);
+        break;
     case BC_TAG_DATE:
         obj = JS_ReadDate(s);
         break;

tests/test_bjson.js

@@ -143,6 +143,18 @@ function bjson_test_reference()
     }
 }
 
+function bjson_test_regexp()
+{
+    var buf, r;
+
+    bjson_test(/xyzzy/);
+    bjson_test(/xyzzy/digu);
+
+    buf = bjson.write(/(?<𝓓𝓸𝓰>dog)/);
+    r = bjson.read(buf, 0, buf.byteLength);
+    assert("sup dog".match(r).groups["𝓓𝓸𝓰"], "dog");
+}
+
 function bjson_test_all()
 {
     var obj;
@@ -171,6 +183,7 @@ function bjson_test_all()
     }
 
     bjson_test_reference();
+    bjson_test_regexp();
 }
 
 bjson_test_all();