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/*
* Copyright 2016 WebAssembly Community Group participants
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "wasm-parser-lexer-shared.h"
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
void wasm_vfprint_error(FILE* error_file,
const WasmLocation* loc,
WasmLexer lexer,
const char* fmt,
va_list args) {
if (loc) {
fprintf(error_file, "%s:%d:%d: ", loc->filename, loc->line,
loc->first_column);
}
vfprintf(error_file, fmt, args);
fprintf(error_file, "\n");
if (loc) {
/* print the line and a cute little caret, like clang */
size_t line_offset = wasm_lexer_get_file_offset_from_line(lexer, loc->line);
FILE* lexer_file = wasm_lexer_get_file(lexer);
long old_offset = ftell(lexer_file);
if (old_offset != -1) {
size_t next_line_offset =
wasm_lexer_get_file_offset_from_line(lexer, loc->line + 1);
if (next_line_offset == WASM_INVALID_LINE_OFFSET) {
/* we haven't gotten to the next line yet. read the file to find it. - 1
because columns are 1-based */
size_t offset = line_offset + (loc->last_column - 1);
next_line_offset = offset;
if (fseek(lexer_file, offset, SEEK_SET) != -1) {
char buffer[256];
while (1) {
size_t bytes_read = fread(buffer, 1, sizeof(buffer), lexer_file);
if (bytes_read <= 0)
break;
char* newline = memchr(buffer, '\n', bytes_read);
if (newline) {
next_line_offset += (newline - buffer);
break;
} else {
next_line_offset += bytes_read;
}
}
}
} else {
/* don't include the newline */
next_line_offset--;
}
#define MAX_LINE 80
size_t line_length = next_line_offset - line_offset;
size_t column_range = loc->last_column - loc->first_column;
size_t start_offset = line_offset;
if (line_length > MAX_LINE) {
line_length = MAX_LINE;
size_t center_on;
if (column_range > MAX_LINE) {
/* the column range doesn't fit, just center on first_column */
center_on = loc->first_column - 1;
} else {
/* the entire range fits, display it all in the center */
center_on = (loc->first_column + loc->last_column) / 2 - 1;
}
if (center_on > MAX_LINE / 2)
start_offset = line_offset + center_on - MAX_LINE / 2;
if (start_offset > next_line_offset - MAX_LINE)
start_offset = next_line_offset - MAX_LINE;
}
const char ellipsis[] = "...";
size_t ellipsis_length = sizeof(ellipsis) - 1;
const char* line_prefix = "";
const char* line_suffix = "";
if (start_offset + line_length != next_line_offset) {
line_suffix = ellipsis;
line_length -= ellipsis_length;
}
if (start_offset != line_offset) {
start_offset += ellipsis_length;
line_length -= ellipsis_length;
line_prefix = ellipsis;
}
if (fseek(lexer_file, start_offset, SEEK_SET) != -1) {
char buffer[MAX_LINE];
size_t bytes_read = fread(buffer, 1, line_length, lexer_file);
if (bytes_read > 0) {
fprintf(error_file, "%s%.*s%s\n", line_prefix, (int)bytes_read,
buffer, line_suffix);
/* print the caret */
char carets[MAX_LINE];
memset(carets, '^', sizeof(carets));
size_t num_spaces = (loc->first_column - 1) -
(start_offset - line_offset) +
strlen(line_prefix);
size_t num_carets = column_range;
if (num_carets > MAX_LINE - num_spaces)
num_carets = MAX_LINE - num_spaces;
fprintf(error_file, "%*s%.*s\n", (int)num_spaces, "", (int)num_carets,
carets);
}
}
if (fseek(lexer_file, old_offset, SEEK_SET) == -1) {
/* we're screwed now, blow up. */
WASM_FATAL("failed to seek.");
}
}
}
}
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