Revert "[skjson] Size-constrained input API"

This reverts commit fc792b8718cc30e9da62c9559b23c1baac3166bb.

Reason for revert: New ASAN, Android failures.

Original change's description:
> [skjson] Size-constrained input API
> 
> Pass an explicit input size instead of requiring a C string.
> 
> Thanks to mtklein's clever trick, this has no measurable perf impact.
> 
> Change-Id: I64f210a9f653a78b05ab6b58fa34479504aa35ff
> Reviewed-on: https://skia-review.googlesource.com/134940
> Reviewed-by: Mike Klein <mtklein@google.com>
> Commit-Queue: Florin Malita <fmalita@chromium.org>

TBR=mtklein@google.com,fmalita@chromium.org

Change-Id: Ic0b52398b1ce6f64c781debb858829cb64bbae58
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/135022
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>

1 files changed, 17 insertions, 31 deletions

diff --git a/modules/skjson/src/SkJSON.cpp b/modules/skjson/src/SkJSON.cpp
index 64f1302a7e..bf176c5c5c 100644
--- a/modules/skjson/src/SkJSON.cpp
+++ b/modules/skjson/src/SkJSON.cpp
@@ -11,12 +11,12 @@
 #include "SkString.h"
 
 #include <cmath>
-#include <tuple>
 #include <vector>
 
 namespace skjson {
 
-// #define SK_JSON_REPORT_ERRORS
+//#define SK_JSON_REPORT_ERRORS
+
 
 static_assert( sizeof(Value) == 8, "");
 static_assert(alignof(Value) == 8, "");
@@ -236,21 +236,7 @@ public:
         fScopeStack.reserve(kScopeStackReserve);
     }
 
-    const Value parse(const char* p, size_t size) {
-        if (!size) {
-            this->error(NullValue(), p, "invalid empty input");
-        }
-
-        const char* p_stop = p + size - 1;
-
-        // We're only checking for end-of-stream on object/array close('}',']'),
-        // so we must trim any whitespace from the buffer tail.
-        while (p_stop > p && is_ws(*p_stop)) --p_stop;
-
-        if (*p_stop != '}' && *p_stop != ']') {
-            return this->error(NullValue(), p_stop, "invalid top-level value");
-        }
-
+    const Value parse(const char* p) {
         p = skip_ws(p);
 
         switch (*p) {
@@ -354,17 +340,17 @@ public:
     pop_common:
         SkASSERT(*p == '}' || *p == ']');
 
+        ++p;
+
         if (fScopeStack.empty()) {
             SkASSERT(fValueStack.size() == 1);
 
-            // Success condition: parsed the top level element and reached the stop token.
-            return p == p_stop
+            // Stop condition: parsed the top level element and there is no trailing garbage.
+            return *skip_ws(p) == '\0'
                 ? fValueStack.front()
-                : this->error(NullValue(), p + 1, "trailing root garbage");
+                : this->error(NullValue(), p, "trailing root garbage");
         }
 
-        ++p;
-
         goto match_post_value;
 
     match_array:
@@ -391,20 +377,19 @@ public:
         return NullValue();
     }
 
-    std::tuple<const char*, const SkString> getError() const {
-        return std::make_tuple(fErrorToken, fErrorMessage);
+    const SkString& getError() const {
+        return fError;
     }
 
 private:
-    SkArenaAlloc&         fAlloc;
+    SkArenaAlloc&                 fAlloc;
 
     static constexpr size_t kValueStackReserve = 256;
     static constexpr size_t kScopeStackReserve = 128;
     std::vector<Value   > fValueStack;
     std::vector<intptr_t> fScopeStack;
 
-    const char*           fErrorToken = nullptr;
-    SkString              fErrorMessage;
+    SkString             fError;
 
     template <typename VectorT>
     void popScopeAsVec(size_t scope_start) {
@@ -505,8 +490,9 @@ private:
     template <typename T>
     T error(T&& ret_val, const char* p, const char* msg) {
 #if defined(SK_JSON_REPORT_ERRORS)
-        fErrorToken = p;
-        fErrorMessage.set(msg);
+        static constexpr size_t kMaxContext = 128;
+        fError = SkStringPrintf("%s: >", msg);
+        fError.append(p, std::min(strlen(p), kMaxContext));
 #endif
         return ret_val;
     }
@@ -732,11 +718,11 @@ SkString Value::toString() const {
 
 static constexpr size_t kMinChunkSize = 4096;
 
-DOM::DOM(const char* data, size_t size)
+DOM::DOM(const char* c_str)
     : fAlloc(kMinChunkSize) {
     DOMParser parser(fAlloc);
 
-    fRoot = parser.parse(data, size);
+    fRoot = parser.parse(c_str);
 }
 
 void DOM::write(SkWStream* stream) const {