[Qemu-devel] [PATCH 35/36] qapi: Rip out dynamic JSON parser escape sequence support

[Eric Blake]

Now that there are no callers of dynamic JSON parsing, the
lexer does not need to special-case escape sequences.

Since the lexer is directly invoked on user-provided input,
this changes behavior when a QMP client passes (bad) JSON,
from:

{'execute':'qmp_capabilities','id':%s}
{"error": {"class": "GenericError", "desc": "Invalid JSON syntax"}}

to the noisier:

{'execute':'qmp_capabilities','id':%s}
{"error": {"class": "GenericError", "desc": "Invalid JSON syntax"}}
{"error": {"class": "GenericError", "desc": "JSON parse error, invalid keyword 
's'"}}
{"error": {"class": "GenericError", "desc": "JSON parse error, expecting 
value"}}

But we've always known our parser is rather noisy when it comes to
dealing with invalid JSON, and valid clients won't see the
difference.

Signed-off-by: Eric Blake <address@hidden>
---
 include/qapi/qmp/json-lexer.h |  1 -
 qobject/json-lexer.c          | 40 ----------------------------------------
 qobject/json-parser.c         | 32 --------------------------------
 3 files changed, 73 deletions(-)

diff --git a/include/qapi/qmp/json-lexer.h b/include/qapi/qmp/json-lexer.h
index afee782..a872f57 100644
--- a/include/qapi/qmp/json-lexer.h
+++ b/include/qapi/qmp/json-lexer.h
@@ -27,7 +27,6 @@ typedef enum json_token_type {
     JSON_FLOAT,
     JSON_KEYWORD,
     JSON_STRING,
-    JSON_ESCAPE,
     JSON_SKIP,
     JSON_ERROR,
 } JSONTokenType;
diff --git a/qobject/json-lexer.c b/qobject/json-lexer.c
index af4a75e..3207306 100644
--- a/qobject/json-lexer.c
+++ b/qobject/json-lexer.c
@@ -58,12 +58,6 @@ enum json_lexer_state {
     IN_NONZERO_NUMBER,
     IN_NEG_NONZERO_NUMBER,
     IN_KEYWORD,
-    IN_ESCAPE,
-    IN_ESCAPE_L,
-    IN_ESCAPE_LL,
-    IN_ESCAPE_I,
-    IN_ESCAPE_I6,
-    IN_ESCAPE_I64,
     IN_WHITESPACE,
     IN_START,
 };
@@ -224,38 +218,6 @@ static const uint8_t json_lexer[][256] =  {
         ['\n'] = IN_WHITESPACE,
     },

-    /* escape */
-    [IN_ESCAPE_LL] = {
-        ['d'] = JSON_ESCAPE,
-    },
-
-    [IN_ESCAPE_L] = {
-        ['d'] = JSON_ESCAPE,
-        ['l'] = IN_ESCAPE_LL,
-    },
-
-    [IN_ESCAPE_I64] = {
-        ['d'] = JSON_ESCAPE,
-    },
-
-    [IN_ESCAPE_I6] = {
-        ['4'] = IN_ESCAPE_I64,
-    },
-
-    [IN_ESCAPE_I] = {
-        ['6'] = IN_ESCAPE_I6,
-    },
-
-    [IN_ESCAPE] = {
-        ['d'] = JSON_ESCAPE,
-        ['i'] = JSON_ESCAPE,
-        ['p'] = JSON_ESCAPE,
-        ['s'] = JSON_ESCAPE,
-        ['f'] = JSON_ESCAPE,
-        ['l'] = IN_ESCAPE_L,
-        ['I'] = IN_ESCAPE_I,
-    },
-
     /* top level rule */
     [IN_START] = {
         ['"'] = IN_DQ_STRING,
@@ -270,7 +232,6 @@ static const uint8_t json_lexer[][256] =  {
         [','] = JSON_COMMA,
         [':'] = JSON_COLON,
         ['a' ... 'z'] = IN_KEYWORD,
-        ['%'] = IN_ESCAPE,
         [' '] = IN_WHITESPACE,
         ['\t'] = IN_WHITESPACE,
         ['\r'] = IN_WHITESPACE,
@@ -311,7 +272,6 @@ static int json_lexer_feed_char(JSONLexer *lexer, char ch, 
bool flush)
         case JSON_RSQUARE:
         case JSON_COLON:
         case JSON_COMMA:
-        case JSON_ESCAPE:
         case JSON_INTEGER:
         case JSON_FLOAT:
         case JSON_KEYWORD:
diff --git a/qobject/json-parser.c b/qobject/json-parser.c
index c18e48a..fec1dae 100644
--- a/qobject/json-parser.c
+++ b/qobject/json-parser.c
@@ -450,36 +450,6 @@ static QObject *parse_keyword(JSONParserContext *ctxt)
     return NULL;
 }

-static QObject *parse_escape(JSONParserContext *ctxt, va_list *ap)
-{
-    JSONToken *token;
-
-    if (ap == NULL) {
-        return NULL;
-    }
-
-    token = parser_context_pop_token(ctxt);
-    assert(token && token->type == JSON_ESCAPE);
-
-    if (!strcmp(token->str, "%p")) {
-        return va_arg(*ap, QObject *);
-    } else if (!strcmp(token->str, "%i")) {
-        return QOBJECT(qbool_from_bool(va_arg(*ap, int)));
-    } else if (!strcmp(token->str, "%d")) {
-        return QOBJECT(qint_from_int(va_arg(*ap, int)));
-    } else if (!strcmp(token->str, "%ld")) {
-        return QOBJECT(qint_from_int(va_arg(*ap, long)));
-    } else if (!strcmp(token->str, "%lld") ||
-               !strcmp(token->str, "%I64d")) {
-        return QOBJECT(qint_from_int(va_arg(*ap, long long)));
-    } else if (!strcmp(token->str, "%s")) {
-        return QOBJECT(qstring_from_str(va_arg(*ap, const char *)));
-    } else if (!strcmp(token->str, "%f")) {
-        return QOBJECT(qfloat_from_double(va_arg(*ap, double)));
-    }
-    return NULL;
-}
-
 static QObject *parse_literal(JSONParserContext *ctxt)
 {
     JSONToken *token;
@@ -537,8 +507,6 @@ static QObject *parse_value(JSONParserContext *ctxt, 
va_list *ap)
         return parse_object(ctxt, ap);
     case JSON_LSQUARE:
         return parse_array(ctxt, ap);
-    case JSON_ESCAPE:
-        return parse_escape(ctxt, ap);
     case JSON_INTEGER:
     case JSON_FLOAT:
     case JSON_STRING:
-- 
2.7.4