Merge topic 'json-bom'

afa4e5f749 cmJSONState: Move BOM handling to shared helper
18a335e062 cmPListParser: Hand JSONState a seekable stream

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !12466

Source/cmJSONState.cxx

@@ -26,8 +26,6 @@ cmJSONState::cmJSONState(std::string jsonFile, Json::Value* root,
     this->AddError(cmStrCat("File not found: ", this->Filename));
     return;
   }
-  // If there's a BOM, toss it.
-  cmsys::FStream::ReadBOM(fin);
 
   this->ReadJSONStream(fin, root, strictMode);
 }
@@ -127,6 +125,9 @@ void cmJSONState::pop_stack()
 void cmJSONState::ReadJSONStream(std::istream& jsonIStream, Json::Value* root,
                                  StrictMode strictMode)
 {
+  // If there's a BOM, toss it.
+  cmsys::FStream::ReadBOM(jsonIStream);
+
   // Save the entire document.
   std::streampos inBegin = jsonIStream.tellg();
   this->doc = std::string(std::istreambuf_iterator<char>(jsonIStream),

Source/cmPlistParser.cxx

@@ -2,6 +2,9 @@
    file LICENSE.rst or https://cmake.org/licensing for details.  */
 #include "cmPlistParser.h"
 
+#include <iterator>
+#include <sstream>
+#include <string>
 #include <vector>
 
 #include <cm3p/json/value.h>
@@ -25,10 +28,16 @@ cm::optional<Json::Value> cmParsePlist(std::string const& filename)
     return cm::nullopt;
   }
 
-  Json::Value value;
+  // Buffer plutil's output into a seekable stream. cmJSONState must be able
+  // peek at a leading BOM, which the process pipe behind cmUVIStream can't
+  // handle.
   cmUVIStream outputStream(chain.OutputStream());
-  cmJSONState parseState(outputStream, &value,
-                         cmJSONState::StrictMode::Relaxed);
+  std::string output{ std::istreambuf_iterator<char>(outputStream),
+                      std::istreambuf_iterator<char>() };
+  std::istringstream jsonStream(output);
+
+  Json::Value value;
+  cmJSONState parseState(jsonStream, &value, cmJSONState::StrictMode::Relaxed);
   if (!parseState.errors.empty()) {
     return cm::nullopt;
   }

Tests/Fuzzing/corpus/json/.gitattributes

@@ -1 +1,2 @@
 array.json -text -whitespace
+bom.json -text -whitespace

Tests/Fuzzing/corpus/json/bom.json

@@ -0,0 +1 @@
+