1 files changed, 163 insertions, 0 deletions
diff --git a/Source/cmJSONState.cxx b/Source/cmJSONState.cxx
new file mode 100644
index 0000000000..92bde778a7
--- /dev/null
+++ b/Source/cmJSONState.cxx
@@ -0,0 +1,163 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+
+#include "cmJSONState.h"
+
+#include <sstream>
+
+#include <cm/memory>
+
+#include <cm3p/json/reader.h>
+#include <cm3p/json/value.h>
+
+#include "cmsys/FStream.hxx"
+
+#include "cmStringAlgorithms.h"
+
+cmJSONState::cmJSONState(const std::string& filename, Json::Value* root)
+{
+  cmsys::ifstream fin(filename.c_str(), std::ios::in | std::ios::binary);
+  if (!fin) {
+    this->AddError(cmStrCat("File not found: ", filename));
+    return;
+  }
+  // If there's a BOM, toss it.
+  cmsys::FStream::ReadBOM(fin);
+
+  // Save the entire document.
+  std::streampos finBegin = fin.tellg();
+  this->doc = std::string(std::istreambuf_iterator<char>(fin),
+                          std::istreambuf_iterator<char>());
+  if (this->doc.empty()) {
+    this->AddError("A JSON document cannot be empty");
+    return;
+  }
+  fin.seekg(finBegin);
+
+  // Parse the document.
+  Json::CharReaderBuilder builder;
+  Json::CharReaderBuilder::strictMode(&builder.settings_);
+  std::string errMsg;
+  if (!Json::parseFromStream(builder, fin, root, &errMsg)) {
+    errMsg = cmStrCat("JSON Parse Error: ", filename, ":\n", errMsg);
+    this->AddError(errMsg);
+  }
+}
+
+void cmJSONState::AddError(std::string const& errMsg)
+{
+  this->errors.push_back(Error(errMsg));
+}
+
+void cmJSONState::AddErrorAtValue(std::string const& errMsg,
+                                  const Json::Value* value)
+{
+  if (value && !value->isNull()) {
+    this->AddErrorAtOffset(errMsg, value->getOffsetStart());
+  } else {
+    this->AddError(errMsg);
+  }
+}
+
+void cmJSONState::AddErrorAtOffset(std::string const& errMsg,
+                                   std::ptrdiff_t offset)
+{
+  if (doc.empty()) {
+    this->AddError(errMsg);
+  } else {
+    Location loc = LocateInDocument(offset);
+    this->errors.push_back(Error(loc, errMsg));
+  }
+}
+
+std::string cmJSONState::GetErrorMessage(bool showContext)
+{
+  std::string message;
+  for (auto const& error : this->errors) {
+    message = cmStrCat(message, error.GetErrorMessage(), "\n");
+    if (showContext) {
+      Location loc = error.GetLocation();
+      if (loc.column > 0) {
+        message = cmStrCat(message, GetJsonContext(loc), "\n");
+      }
+    }
+  }
+  message = cmStrCat("\n", message);
+  message.pop_back();
+  return message;
+}
+
+std::string cmJSONState::key()
+{
+  if (!this->parseStack.empty()) {
+    return this->parseStack.back().first;
+  }
+  return "";
+}
+
+std::string cmJSONState::key_after(std::string const& k)
+{
+  for (auto it = this->parseStack.begin(); it != this->parseStack.end();
+       ++it) {
+    if (it->first == k && (++it) != this->parseStack.end()) {
+      return it->first;
+    }
+  }
+  return "";
+}
+
+const Json::Value* cmJSONState::value_after(std::string const& k)
+{
+  for (auto it = this->parseStack.begin(); it != this->parseStack.end();
+       ++it) {
+    if (it->first == k && (++it) != this->parseStack.end()) {
+      return it->second;
+    }
+  }
+  return nullptr;
+}
+
+void cmJSONState::push_stack(std::string const& k, const Json::Value* value)
+{
+  this->parseStack.push_back(JsonPair(k, value));
+}
+
+void cmJSONState::pop_stack()
+{
+  this->parseStack.pop_back();
+}
+
+std::string cmJSONState::GetJsonContext(Location loc)
+{
+  std::string line;
+  std::stringstream sstream(doc);
+  for (int i = 0; i < loc.line; ++i) {
+    std::getline(sstream, line, '\n');
+  }
+  return cmStrCat(line, '\n', std::string(loc.column - 1, ' '), '^');
+}
+
+cmJSONState::Location cmJSONState::LocateInDocument(ptrdiff_t offset)
+{
+  int line = 1;
+  int col = 1;
+  const char* beginDoc = doc.data();
+  const char* last = beginDoc + offset;
+  for (; beginDoc != last; ++beginDoc) {
+    switch (*beginDoc) {
+      case '\r':
+        if (beginDoc + 1 != last && beginDoc[1] == '\n') {
+          continue; // consume CRLF as a single token.
+        }
+        CM_FALLTHROUGH; // CR without a following LF is same as LF
+      case '\n':
+        col = 1;
+        ++line;
+        break;
+      default:
+        ++col;
+        break;
+    }
+  }
+  return { line, col };
+}