Storage: Storage.writeJSON now skips quotes on alphanumeric field nam…

…es to speed up settings read/write

see #2429 (comment)

ChangeLog

@@ -33,6 +33,7 @@
             Fix `Got [ERASED] expecting X` when storage compacts while executing a function *in* storage on non-Bangle devices (fix #2431)
             JIT: Fix crashes when code got too big for simple 2-byte jump instructions (fix #2433)
             JIT: Fixed/re-added while loops (and DO for huge loops)
+            Storage: Storage.writeJSON now skips quotes on alphanumeric field names to speed up settings read/write
 
      2v19 : Fix Object.values/entries for numeric keys after 2v18 regression (fix #2375)
             nRF52: for SD>5 use static buffers for advertising and scan response data (#2367)

src/jswrap_json.c

@@ -80,15 +80,17 @@ JsVar *jswrap_json_stringify(JsVar *v, JsVar *replacer, JsVar *space) {
 }
 
 
-JsVar *jswrap_json_parse_internal() {
+/* Parse JSON from the current lexer. unquoted fields aren't normally allowed,
+   but if flags&JSON_DROP_QUOTES we'll allow them */
+JsVar *jswrap_json_parse_internal(JSONFlags flags) {
   switch (lex->tk) {
   case LEX_R_TRUE:  jslGetNextToken(); return jsvNewFromBool(true);
   case LEX_R_FALSE: jslGetNextToken(); return jsvNewFromBool(false);
   case LEX_R_NULL:  jslGetNextToken(); return jsvNewWithFlags(JSV_NULL);
   case '-': {
     jslGetNextToken();
     if (lex->tk!=LEX_INT && lex->tk!=LEX_FLOAT) return 0;
-    JsVar *v = jswrap_json_parse_internal();
+    JsVar *v = jswrap_json_parse_internal(flags);
     JsVar *zero = jsvNewFromInteger(0);
     JsVar *r = jsvMathsOp(zero, v, '-');
     jsvUnLock2(v, zero);
@@ -117,7 +119,7 @@ JsVar *jswrap_json_parse_internal() {
     JsVar *arr = jsvNewEmptyArray(); if (!arr) return 0;
     jslGetNextToken(); // [
     while (lex->tk != ']' && !jspHasError()) {
-      JsVar *value = jswrap_json_parse_internal();
+      JsVar *value = jswrap_json_parse_internal(flags);
       if (!value ||
           (lex->tk!=']' && !jslMatch(','))) {
         jsvUnLock2(value, arr);
@@ -135,12 +137,16 @@ JsVar *jswrap_json_parse_internal() {
   case '{': {
     JsVar *obj = jsvNewObject(); if (!obj) return 0;
     jslGetNextToken(); // {
-    while (lex->tk == LEX_STR && !jspHasError()) {
+    while (lex->tk == LEX_STR || lex->tk == LEX_ID && !jspHasError()) {
+      if (!(flags&JSON_DROP_QUOTES)) {
+        jslMatch(LEX_STR);
+        return obj;
+      }
       JsVar *key = jsvAsArrayIndexAndUnLock(jslGetTokenValueAsVar());
       jslGetNextToken();
       JsVar *value = 0;
       if (!jslMatch(':') ||
-          !(value=jswrap_json_parse_internal()) ||
+          !(value=jswrap_json_parse_internal(flags)) ||
           (lex->tk!='}' && !jslMatch(','))) {
         jsvUnLock3(key, value, obj);
         return 0;
@@ -178,17 +184,20 @@ Parse the given JSON string into a JavaScript object
 NOTE: This implementation uses eval() internally, and as such it is unsafe as it
 can allow arbitrary JS commands to be executed.
  */
-JsVar *jswrap_json_parse(JsVar *v) {
+JsVar *jswrap_json_parse_ext(JsVar *v, JSONFlags flags) {
   JsLex lex;
   JsVar *str = jsvAsString(v);
   JsLex *oldLex = jslSetLex(&lex);
   jslInit(str);
   jsvUnLock(str);
-  JsVar *res = jswrap_json_parse_internal();
+  JsVar *res = jswrap_json_parse_internal(flags);
   jslKill();
   jslSetLex(oldLex);
   return res;
 }
+JsVar *jswrap_json_parse(JsVar *v) {
+  return jswrap_json_parse_ext(v, 0);
+}
 
 /* This is like jsfGetJSONWithCallback, but handles ONLY functions (and does not print the initial 'function' text) */
 void jsfGetJSONForFunctionWithCallback(JsVar *var, JSONFlags flags, vcbprintf_callback user_callback, void *user_data) {

src/jswrap_json.h

@@ -16,10 +16,6 @@
 
 #include "jsvar.h"
 
-JsVar *jswrap_json_stringify(JsVar *v, JsVar *replacer, JsVar *space);
-JsVar *jswrap_json_parse_ext(JsVar *v, bool throwExceptions);
-JsVar *jswrap_json_parse(JsVar *v);
-
 typedef enum {
   JSON_NONE,
   JSON_SOME_NEWLINES     = 1, //< insert newlines in non-simple arrays and objects
@@ -31,7 +27,7 @@ typedef enum {
   JSON_NO_UNDEFINED      = 64, //< don't output undefined keys in objects, and use null for undefined in arrays
   JSON_ARRAYBUFFER_AS_ARRAY = 128, //< dump arraybuffers as arrays
   JSON_SHOW_OBJECT_NAMES    = 256, //< Show 'Promise {}'/etc for objects if the type is global
-  JSON_DROP_QUOTES          = 512, //< When outputting objects, drop quotes for alphanumeric field names
+  JSON_DROP_QUOTES          = 512, //< When outputting objects, drop quotes for alphanumeric field names (or allow unqouted when parsing)
   JSON_PIN_TO_STRING        = 1024, //< Convert pins to Strings
   JSON_ALL_UNICODE_ESCAPE   = 2048, //< Only use unicode \xXXXX for escape characters, not \xXX or \X
   JSON_NO_NAN               = 4096, //< Don't output NaN for NaN numbers, only 'null'
@@ -41,6 +37,10 @@ typedef enum {
   JSON_INDENT            = 16384, // MUST BE THE LAST ENTRY IN JSONFlags - we use this to count the amount of indents
 } JSONFlags;
 
+JsVar *jswrap_json_stringify(JsVar *v, JsVar *replacer, JsVar *space);
+JsVar *jswrap_json_parse_ext(JsVar *v, JSONFlags flags);
+JsVar *jswrap_json_parse(JsVar *v);
+
 /* This is like jsfGetJSONWithCallback, but handles ONLY functions (and does not print the initial 'function' text) */
 void jsfGetJSONForFunctionWithCallback(JsVar *var, JSONFlags flags, vcbprintf_callback user_callback, void *user_data);
 /* Dump to JSON, using the given callbacks for printing data

src/jswrap_storage.c

@@ -160,7 +160,7 @@ created with `require("Storage").open(filename, ...)`
 JsVar *jswrap_storage_readJSON(JsVar *name, bool noExceptions) {
   JsVar *v = jsfReadFile(jsfNameFromVar(name),0,0);
   if (!v) return 0;
-  JsVar *r = jswrap_json_parse(v);
+  JsVar *r = jswrap_json_parse_ext(v, JSON_DROP_QUOTES);
   jsvUnLock(v);
   if (noExceptions) {
     jsvUnLock(jspGetException());
@@ -288,23 +288,25 @@ disappear when the device resets or power is lost.
 Simply write `require("Storage").writeJSON("MyFile", [1,2,3])` to write a new
 file, and `require("Storage").readJSON("MyFile")` to read it.
 
-This is (almost) equivalent to: `require("Storage").write(name, JSON.stringify(data))`
+This is (almost) equivalent to `require("Storage").write(name, JSON.stringify(data))` (see the notes below)
 
 **Note:** This function should be used with normal files, and not `StorageFile`s
 created with `require("Storage").open(filename, ...)`
 
 **Note:** Normally `JSON.stringify` converts any non-standard character to an escape code with `\uXXXX`, but
-as of Espruino 2v20, when writing to a file we use the most compact form, like `\xXX` or `\X`. This saves
-space and is faster, but also means that if a String wasn't a UTF8 string but contained characters in the UTF8 codepoint range,
-when saved it won't end up getting reloaded as a UTF8 string.
+as of Espruino 2v20, when writing to a file we use the most compact form, like `\xXX` or `\X`, as well as
+skipping quotes on fields. This saves space and is faster, but also means that if a String wasn't a UTF8
+string but contained characters in the UTF8 codepoint range, when saved it won't end up getting reloaded as a UTF8 string.
+It does mean that you cannot parse the file with just `JSON.parse` as it's no longer standard JSON but is JS,
+so you must use `Storage.readJSON`
 */
 bool jswrap_storage_writeJSON(JsVar *name, JsVar *data) {
   JsVar *d = jsvNewFromEmptyString();
   if (!d) return false;
   /* Don't call jswrap_json_stringify directly because we want to ensure we don't use JSON_JSON_COMPATIBILE, so
   String escapes like `\xFC` stay as `\xFC` and not `\u00FC` to save space and help with unicode compatibility
   */
-  jsfGetJSON(data, d, (JSON_IGNORE_FUNCTIONS|JSON_NO_UNDEFINED|JSON_ARRAYBUFFER_AS_ARRAY|JSON_JSON_COMPATIBILE) &~JSON_ALL_UNICODE_ESCAPE);
+  jsfGetJSON(data, d, (JSON_DROP_QUOTES|JSON_IGNORE_FUNCTIONS|JSON_NO_UNDEFINED|JSON_ARRAYBUFFER_AS_ARRAY|JSON_JSON_COMPATIBILE) &~JSON_ALL_UNICODE_ESCAPE);
   bool r = jsfWriteFile(jsfNameFromVar(name), d, JSFF_NONE, 0, 0);
   jsvUnLock(d);
   return r;