mirror of
https://github.com/NixOS/nix
synced 2024-09-21 11:30:30 -04:00
7db08cc924
buggy. It fails to clear an internal variable (SG_textIndex) between invocations, so it can be called only once during a program execution.
149 lines
3.8 KiB
C++
149 lines
3.8 KiB
C++
#include <sstream>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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extern "C" {
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#include <sglr.h>
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#include <asfix2.h>
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}
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#include "parser.hh"
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#include "shared.hh"
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#include "fix-expr.hh"
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#include "expr.hh"
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#include "parse-table.h"
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/* Cleanup cleans up an imploded parse tree into an actual abstract
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syntax tree that we can evaluate. It removes quotes around
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strings, converts integer literals into actual integers, and
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absolutises paths relative to the directory containing the input
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file. */
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struct Cleanup : TermFun
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{
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string basePath;
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virtual ATerm operator () (ATerm e)
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{
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char * s;
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if (ATmatch(e, "Str(<str>)", &s)) {
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string s2(s);
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return ATmake("Str(<str>)",
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string(s2, 1, s2.size() - 2).c_str());
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}
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if (ATmatch(e, "Path(<str>)", &s)) {
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string path(s);
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if (path[0] != '/')
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path = basePath + "/" + path;
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return ATmake("Str(<str>)", canonPath(path).c_str());
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}
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if (ATmatch(e, "Int(<str>)", &s)) {
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istringstream s2(s);
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int n;
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s2 >> n;
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return ATmake("Int(<int>)", n);
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}
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return e;
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}
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};
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Expr parseExprFromFile(Path path)
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{
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#if 0
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/* Perhaps this is already an imploded parse tree? */
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Expr e = ATreadFromNamedFile(path.c_str());
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if (e) return e;
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#endif
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/* If `path' refers to a directory, append `/default.fix'. */
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struct stat st;
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if (stat(path.c_str(), &st))
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throw SysError(format("getting status of `%1%'") % path);
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if (S_ISDIR(st.st_mode))
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path = canonPath(path + "/default.fix");
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/* Initialise the SDF libraries. */
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static bool initialised = false;
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static ATerm parseTable = 0;
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static language lang = 0;
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if (!initialised) {
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PT_initMEPTApi();
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PT_initAsFix2Api();
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SGinitParser(ATfalse);
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ATprotect(&parseTable);
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parseTable = ATreadFromBinaryString(
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(char *) fixParseTable, sizeof fixParseTable);
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if (!parseTable)
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throw Error(format("cannot construct parse table term"));
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ATprotect(&lang);
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lang = ATmake("Fix");
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if (!SGopenLanguageFromTerm(
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(char *) programId.c_str(), lang, parseTable))
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throw Error(format("cannot open language"));
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SG_STARTSYMBOL_ON();
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SG_OUTPUT_ON();
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SG_ASFIX2ME_ON();
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SG_AMBIGUITY_ERROR_ON();
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initialised = true;
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}
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/* Read the input file. We can't use SGparseFile() because it's
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broken, so we read the input ourselves and call
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SGparseString(). */
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AutoCloseFD fd = open(path.c_str(), O_RDONLY);
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if (fd == -1) throw SysError(format("opening `%1%'") % path);
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if (fstat(fd, &st) == -1)
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throw SysError(format("statting `%1%'") % path);
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char text[st.st_size + 1];
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readFull(fd, (unsigned char *) text, st.st_size);
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text[st.st_size] = 0;
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/* Parse it. */
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ATerm result = SGparseString(lang, "Expr", text);
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if (!result)
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throw SysError(format("parse failed in `%1%'") % path);
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if (SGisParseError(result))
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throw Error(format("parse error in `%1%': %2%")
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% path % printTerm(result));
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/* Implode it. */
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PT_ParseTree tree = PT_makeParseTreeFromTerm(result);
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if (!tree)
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throw Error(format("cannot create parse tree"));
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ATerm imploded = PT_implodeParseTree(tree,
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ATtrue,
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ATtrue,
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ATtrue,
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ATtrue,
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ATtrue,
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ATtrue,
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ATfalse,
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ATtrue,
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ATtrue,
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ATtrue,
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ATfalse);
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if (!imploded)
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throw Error(format("cannot implode parse tree"));
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/* Finally, clean it up. */
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Cleanup cleanup;
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cleanup.basePath = dirOf(path);
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return bottomupRewrite(cleanup, imploded);
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}
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