OpenBSD-4.6/usr.bin/make/lowparse.c
/* $OpenPackages$ */
/* $OpenBSD: lowparse.c,v 1.22 2007/09/22 10:43:38 espie Exp $ */
/* low-level parsing functions. */
/*
* Copyright (c) 1999,2000 Marc Espie.
*
* Extensive code changes for the OpenBSD project.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD
* PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <assert.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "config.h"
#include "defines.h"
#include "buf.h"
#include "lowparse.h"
#include "error.h"
#include "lst.h"
#include "memory.h"
/* XXX check whether we can free filenames at the end, for a proper
* definition of `end'. */
#if 0
static LIST fileNames; /* file names to free at end */
#endif
/* Input stream structure: file or string.
* Files have str == NULL, F != NULL.
* Strings have F == NULL, str != NULL.
*/
struct input_stream {
const char *fname; /* Name of file */
unsigned long lineno; /* Line number */
FILE *F; /* Open stream, or NULL if pure string. */
char *str; /* Input string, if F == NULL. */
/* Line buffer. */
char *ptr; /* Where we are. */
char *end; /* Don't overdo it. */
};
static struct input_stream *current; /* the input_stream being parsed. */
static LIST input_stack; /* Stack of input_stream waiting to be parsed
* (includes and loop reparses) */
/* input_stream ctors.
*
* obj = new_input_file(filename, filehandle);
* Create input stream from filename, filehandle. */
static struct input_stream *new_input_file(const char *, FILE *);
/* obj = new_input_string(str, filename, lineno);
* Create input stream from str, filename, lineno. */
static struct input_stream *new_input_string(char *, const char *, unsigned long);
/* free_input_stream(obj);
* Discard consumed input stream, closing files, freeing memory. */
static void free_input_stream(struct input_stream *);
/* Handling basic character reading.
* c = read_char();
* New character c from current input stream, or EOF at end of stream. */
#define read_char() \
current->ptr < current->end ? *current->ptr++ : grab_new_line_and_readchar()
/* char = grab_new_line_and_readchar();
* Guts for read_char. Grabs a new line off fgetln when we have
* consumed the current line and returns the first char, or EOF at end of
* stream. */
static int grab_new_line_and_readchar(void);
/* c = skip_to_end_of_line();
* Skips to the end of the current line, returns either '\n' or EOF. */
static int skip_to_end_of_line(void);
/* Helper functions to handle basic parsing. */
/* read_logical_line(buffer, firstchar);
* Grabs logical line into buffer, the first character has already been
* read into firstchar. */
static void read_logical_line(Buffer, int);
/* firstchar = ParseSkipEmptyLines(buffer);
* Scans lines, skipping empty lines. May put some characters into
* buffer, returns the first character useful to continue parsing
* (e.g., not a backslash or a space. */
static int skip_empty_lines_and_read_char(Buffer);
static struct input_stream *
new_input_file(const char *name, FILE *stream)
{
struct input_stream *istream;
#if 0
Lst_AtEnd(&fileNames, name);
#endif
istream = emalloc(sizeof(*istream));
istream->fname = name;
istream->str = NULL;
/* Naturally enough, we start reading at line 0. */
istream->lineno = 0;
istream->F = stream;
istream->ptr = istream->end = NULL;
return istream;
}
static void
free_input_stream(struct input_stream *istream)
{
if (istream->F && fileno(istream->F) != STDIN_FILENO)
(void)fclose(istream->F);
free(istream->str);
/* Note we can't free the file names yet, as they are embedded in GN
* for error reports. */
free(istream);
}
static struct input_stream *
new_input_string(char *str, const char *name, unsigned long lineno)
{
struct input_stream *istream;
istream = emalloc(sizeof(*istream));
/* No malloc, name is always taken from an already existing istream */
istream->fname = name;
istream->F = NULL;
/* Strings are used in for loops, so we need to reset the line counter
* to an appropriate value. */
istream->lineno = lineno;
istream->ptr = istream->str = str;
istream->end = str + strlen(str);
return istream;
}
void
Parse_FromString(char *str, unsigned long lineno)
{
if (DEBUG(FOR))
(void)fprintf(stderr, "%s\n----\n", str);
if (current != NULL)
Lst_Push(&input_stack, current);
current = new_input_string(str, current->fname, lineno);
}
void
Parse_FromFile(const char *name, FILE *stream)
{
if (current != NULL)
Lst_Push(&input_stack, current);
current = new_input_file(name, stream);
}
bool
Parse_NextFile(void)
{
if (current != NULL)
free_input_stream(current);
current = (struct input_stream *)Lst_Pop(&input_stack);
return current != NULL;
}
static int
grab_new_line_and_readchar(void)
{
size_t len;
if (current->F) {
current->ptr = fgetln(current->F, &len);
if (current->ptr) {
current->end = current->ptr + len;
return *current->ptr++;
} else {
current->end = NULL;
}
}
return EOF;
}
static int
skip_to_end_of_line(void)
{
if (current->F) {
if (current->end - current->ptr > 1)
current->ptr = current->end - 1;
if (*current->ptr == '\n')
return *current->ptr++;
return EOF;
} else {
int c;
do {
c = read_char();
} while (c != '\n' && c != EOF);
return c;
}
}
char *
Parse_ReadNextConditionalLine(Buffer linebuf)
{
int c;
/* If first char isn't dot, skip to end of line, handling \ */
while ((c = read_char()) != '.') {
for (;c != '\n'; c = read_char()) {
if (c == '\\') {
c = read_char();
if (c == '\n')
current->lineno++;
}
if (c == EOF) {
Parse_Error(PARSE_FATAL,
"Unclosed conditional");
return NULL;
}
}
current->lineno++;
}
/* This is the line we need to copy */
return Parse_ReadUnparsedLine(linebuf, "conditional");
}
static void
read_logical_line(Buffer linebuf, int c)
{
for (;;) {
if (c == '\n') {
current->lineno++;
break;
}
if (c == EOF)
break;
Buf_AddChar(linebuf, c);
c = read_char();
while (c == '\\') {
c = read_char();
if (c == '\n') {
Buf_AddSpace(linebuf);
current->lineno++;
do {
c = read_char();
} while (c == ' ' || c == '\t');
} else {
Buf_AddChar(linebuf, '\\');
if (c == '\\') {
Buf_AddChar(linebuf, '\\');
c = read_char();
}
break;
}
}
}
}
char *
Parse_ReadUnparsedLine(Buffer linebuf, const char *type)
{
int c;
Buf_Reset(linebuf);
c = read_char();
if (c == EOF) {
Parse_Error(PARSE_FATAL, "Unclosed %s", type);
return NULL;
}
/* Handle '\' at beginning of line, since \\n needs special treatment */
while (c == '\\') {
c = read_char();
if (c == '\n') {
current->lineno++;
do {
c = read_char();
} while (c == ' ' || c == '\t');
} else {
Buf_AddChar(linebuf, '\\');
if (c == '\\') {
Buf_AddChar(linebuf, '\\');
c = read_char();
}
break;
}
}
read_logical_line(linebuf, c);
return Buf_Retrieve(linebuf);
}
/* This is a fairly complex function, but without it, we could not skip
* blocks of comments without reading them. */
static int
skip_empty_lines_and_read_char(Buffer linebuf)
{
int c; /* the current character */
for (;;) {
Buf_Reset(linebuf);
c = read_char();
/* Strip leading spaces, fold on '\n' */
if (c == ' ') {
do {
c = read_char();
} while (c == ' ' || c == '\t');
while (c == '\\') {
c = read_char();
if (c == '\n') {
current->lineno++;
do {
c = read_char();
} while (c == ' ' || c == '\t');
} else {
Buf_AddChar(linebuf, '\\');
if (c == '\\') {
Buf_AddChar(linebuf, '\\');
c = read_char();
}
if (c == EOF)
return '\n';
else
return c;
}
}
assert(c != '\t');
}
if (c == '#')
c = skip_to_end_of_line();
/* Almost identical to spaces, except this occurs after
* comments have been taken care of, and we keep the tab
* itself. */
if (c == '\t') {
Buf_AddChar(linebuf, '\t');
do {
c = read_char();
} while (c == ' ' || c == '\t');
while (c == '\\') {
c = read_char();
if (c == '\n') {
current->lineno++;
do {
c = read_char();
} while (c == ' ' || c == '\t');
} else {
Buf_AddChar(linebuf, '\\');
if (c == '\\') {
Buf_AddChar(linebuf, '\\');
c = read_char();
}
if (c == EOF)
return '\n';
else
return c;
}
}
}
if (c == '\n')
current->lineno++;
else
return c;
}
}
/* Parse_ReadNormalLine removes beginning and trailing blanks (but keeps
* the first tab), handles escaped newlines, and skips over uninteresting
* lines.
*
* The line number is incremented, which implies that continuation
* lines are numbered with the last line number (we could do better, at a
* price).
*
* Trivial comments are also removed, but we can't do more, as
* we don't know which lines are shell commands or not. */
char *
Parse_ReadNormalLine(Buffer linebuf)
{
int c; /* the current character */
c = skip_empty_lines_and_read_char(linebuf);
if (c == EOF)
return NULL;
else {
read_logical_line(linebuf, c);
Buf_KillTrailingSpaces(linebuf);
return Buf_Retrieve(linebuf);
}
}
unsigned long
Parse_Getlineno(void)
{
return current ? current->lineno : 0;
}
const char *
Parse_Getfilename(void)
{
return current ? current->fname : NULL;
}
#ifdef CLEANUP
void
LowParse_Init(void)
{
Static_Lst_Init(&input_stack);
current = NULL;
}
void
LowParse_End(void)
{
Lst_Destroy(&input_stack, NOFREE); /* Should be empty now */
#if 0
Lst_Destroy(&fileNames, (SimpleProc)free);
#endif
}
#endif
void
Parse_ReportErrors(void)
{
if (fatal_errors) {
#ifdef CLEANUP
while (Parse_NextFile())
;
#endif
fprintf(stderr,
"Fatal errors encountered -- cannot continue\n");
exit(1);
} else
assert(current == NULL);
}