llama.cpp/examples/gbnf-validator/gbnf-validator.cpp
Daniel Bevenius e6bf007744
llama : return nullptr from llama_grammar_init (#8093)
* llama : return nullptr from llama_grammar_init

This commit updates llama_grammar_init to return nullptr instead of
throwing an exception.

The motivation for this is that this function is declared inside an
extern "C" block and is intended/may be used from C code which will not
be able to handle exceptions thrown, and results in undefined behavior.

On Windows and using MSVC the following warning is currently generated:
```console
C:\llama.cpp\llama.cpp(13998,1): warning C4297: 'llama_grammar_init':
function assumed not to throw an exception but does
C:\llama.cpp\llama.cpp(13998,1): message :
__declspec(nothrow), throw(), noexcept(true), or noexcept was specified
on the function
```

Signed-off-by: Daniel Bevenius <daniel.bevenius@gmail.com>

* squash! llama : return nullptr from llama_grammar_init

Add checks for nullptr when calling llama_grammar_init.

Signed-off-by: Daniel Bevenius <daniel.bevenius@gmail.com>

---------

Signed-off-by: Daniel Bevenius <daniel.bevenius@gmail.com>
Co-authored-by: Clint Herron <hanclinto@gmail.com>
2024-06-25 15:07:28 -04:00

133 lines
4.2 KiB
C++

#define LLAMA_API_INTERNAL
#include "grammar-parser.h"
#include "ggml.h"
#include "llama.h"
#include "unicode.h"
#include <cstdio>
#include <cstdlib>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
static bool llama_sample_grammar_string(struct llama_grammar * grammar, const std::string & input_str, size_t & error_pos, std::string & error_msg) {
auto decoded = decode_utf8(input_str, {});
const auto & code_points = decoded.first;
size_t pos = 0;
for (auto it = code_points.begin(), end = code_points.end() - 1; it != end; ++it) {
auto prev_stacks = grammar->stacks;
llama_grammar_accept(grammar->rules, prev_stacks, *it, grammar->stacks);
if (grammar->stacks.empty()) {
error_pos = pos;
error_msg = "Unexpected character '" + unicode_cpt_to_utf8(*it) + "'";
grammar->stacks = prev_stacks;
return false;
}
++pos;
}
for (const auto & stack : grammar->stacks) {
if (stack.empty()) {
return true;
}
}
error_pos = pos;
error_msg = "Unexpected end of input";
return false;
}
static void print_error_message(const std::string & input_str, size_t error_pos, const std::string & error_msg) {
fprintf(stdout, "Input string is invalid according to the grammar.\n");
fprintf(stdout, "Error: %s at position %zu\n", error_msg.c_str(), error_pos);
fprintf(stdout, "\n");
fprintf(stdout, "Input string:\n");
fprintf(stdout, "%s", input_str.substr(0, error_pos).c_str());
if (error_pos < input_str.size()) {
fprintf(stdout, "\033[1;31m%c", input_str[error_pos]);
if (error_pos+1 < input_str.size()) {
fprintf(stdout, "\033[0;31m%s", input_str.substr(error_pos+1).c_str());
}
fprintf(stdout, "\033[0m\n");
}
}
int main(int argc, char** argv) {
if (argc != 3) {
fprintf(stdout, "Usage: %s <grammar_filename> <input_filename>\n", argv[0]);
return 1;
}
const std::string grammar_filename = argv[1];
const std::string input_filename = argv[2];
// Read the GBNF grammar file
FILE* grammar_file = fopen(grammar_filename.c_str(), "r");
if (!grammar_file) {
fprintf(stdout, "Failed to open grammar file: %s\n", grammar_filename.c_str());
return 1;
}
std::string grammar_str;
{
std::ifstream grammar_file(grammar_filename);
GGML_ASSERT(grammar_file.is_open() && "Failed to open grammar file");
std::stringstream buffer;
buffer << grammar_file.rdbuf();
grammar_str = buffer.str();
}
// Parse the GBNF grammar
auto parsed_grammar = grammar_parser::parse(grammar_str.c_str());
// will be empty (default) if there are parse errors
if (parsed_grammar.rules.empty()) {
fprintf(stdout, "%s: failed to parse grammar\n", __func__);
return 1;
}
// Ensure that there is a "root" node.
if (parsed_grammar.symbol_ids.find("root") == parsed_grammar.symbol_ids.end()) {
fprintf(stdout, "%s: grammar does not contain a 'root' symbol\n", __func__);
return 1;
}
std::vector<const llama_grammar_element *> grammar_rules(parsed_grammar.c_rules());
// Create the LLAMA grammar
auto grammar = llama_grammar_init(
grammar_rules.data(),
grammar_rules.size(), parsed_grammar.symbol_ids.at("root"));
if (grammar == nullptr) {
throw std::runtime_error("Failed to initialize llama_grammar");
}
// Read the input file
std::string input_str;
{
std::ifstream input_file(input_filename);
GGML_ASSERT(input_file.is_open() && "Failed to open input file");
std::stringstream buffer;
buffer << input_file.rdbuf();
input_str = buffer.str();
}
// Validate the input string against the grammar
size_t error_pos;
std::string error_msg;
bool is_valid = llama_sample_grammar_string(grammar, input_str, error_pos, error_msg);
if (is_valid) {
fprintf(stdout, "Input string is valid according to the grammar.\n");
} else {
print_error_message(input_str, error_pos, error_msg);
}
// Clean up
llama_grammar_free(grammar);
return 0;
}