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#include "eval.h"
#include "json.h"
#include <util/string/cast.h>
#include <util/system/guard.h>
#include <util/stream/mem.h>
#include <util/string/builder.h>
TLuaEval::TLuaEval()
: FunctionNameCounter_(0)
{
LuaState_.BootStrap();
}
void TLuaEval::SetVariable(TZtStringBuf name, const NJson::TJsonValue& value) {
TGuard<TMutex> guard(LuaMutex_);
NLua::PushJsonValue(&LuaState_, value);
LuaState_.set_global(name.c_str());
}
void TLuaEval::RunExpressionLocked(const TGuard<TMutex>&, const TExpression& expr) {
LuaState_.push_global(expr.Name.c_str());
LuaState_.call(0, 1);
}
TString TLuaEval::EvalCompiled(const TExpression& expr) {
TGuard<TMutex> guard(LuaMutex_);
RunExpressionLocked(guard, expr);
return LuaState_.pop_value();
}
void TLuaEval::EvalCompiledRaw(const TExpression& expr) {
TGuard<TMutex> guard(LuaMutex_);
RunExpressionLocked(guard, expr);
}
bool TLuaEval::EvalCompiledCondition(const TExpression& expr) {
TGuard<TMutex> guard(LuaMutex_);
RunExpressionLocked(guard, expr);
return LuaState_.pop_bool_strict();
}
TString TLuaEval::EvalRaw(TStringBuf code) {
TMemoryInput bodyIn(code.data(), code.size());
LuaState_.Load(&bodyIn, "main");
LuaState_.call(0, 1);
return LuaState_.pop_value();
}
void TLuaEval::ParseChunk(TStringBuf code) {
TMemoryInput in(code.data(), code.size());
LuaState_.Load(&in, "chunk_" + GenerateName());
LuaState_.call(0, 0);
}
TString TLuaEval::EvalExpression(TStringBuf expression) {
const auto expr = Compile(expression);
try {
return EvalCompiled(expr);
} catch (const yexception& e) {
throw yexception(e) << '\n' << expression;
}
}
TLuaEval::TExpression TLuaEval::Compile(TStringBuf expression) {
TGuard<TMutex> guard(LuaMutex_);
TString name = GenerateName();
TString body = "function ";
body += name;
body += "()\n\treturn (";
body += expression;
body += ")\nend\n";
try {
TMemoryInput bodyIn(body.c_str(), body.size());
LuaState_.Load(&bodyIn, "chunk_" + name);
LuaState_.call(0, 0);
} catch (const yexception& e) {
ythrow yexception(e) << "\n"
<< body;
}
return {name};
}
TLuaEval::TExpression TLuaEval::CompileFunction(TStringBuf expression) {
TString name = GenerateName();
TStringBuilder body;
body << "function " << name << "()" << Endl
<< expression << Endl
<< "end";
return CompileRaw(TStringBuf(body.data(), body.size()), name);
}
TLuaEval::TExpression TLuaEval::CompileRaw(TStringBuf body, const TString& name) {
TGuard<TMutex> guard(LuaMutex_);
try {
TMemoryInput bodyIn(body.data(), body.size());
LuaState_.Load(&bodyIn, "chunk_" + name);
LuaState_.call(0, 0);
} catch (const yexception& e) {
ythrow yexception(e) << "\n" << body;
}
return { name };
}
TString TLuaEval::GenerateName() {
TGuard<TMutex> guard(LuaMutex_);
return "dummy_" + ToString(FunctionNameCounter_++);
}
template <class T>
static inline T FindEnd(T b, T e) {
size_t cnt = 0;
while (b < e) {
switch (*b) {
case '{':
++cnt;
break;
case '}':
if (cnt == 0) {
return b;
}
--cnt;
break;
}
++b;
}
return b;
}
TString TLuaEval::PreprocessOne(TStringBuf line) {
const size_t pos = line.find("${");
if (pos == TStringBuf::npos) {
return EvalExpression(line);
}
const char* rpos = FindEnd(line.data() + pos + 2, line.end());
if (rpos == line.end()) {
ythrow yexception() << TStringBuf("can not parse ") << line;
}
const TStringBuf before = line.SubStr(0, pos);
const TStringBuf after = TStringBuf(rpos + 1, line.end());
const TStringBuf code = TStringBuf(line.data() + pos + 2, rpos);
TString res;
if (code.find("${") == TStringBuf::npos) {
res = EvalExpression(code);
} else {
res = EvalExpression(Preprocess(code));
}
return ToString(before) + res + ToString(after);
}
TString TLuaEval::Preprocess(TStringBuf line) {
TString res = ToString(line);
while (res.find("${") != TString::npos) {
res = PreprocessOne(res);
}
return res;
}
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