diff options
Diffstat (limited to 'third_party/nix/src/libexpr/parser.cc')
| -rw-r--r-- | third_party/nix/src/libexpr/parser.cc | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/third_party/nix/src/libexpr/parser.cc b/third_party/nix/src/libexpr/parser.cc new file mode 100644 index 000000000000..aea6cec7e445 --- /dev/null +++ b/third_party/nix/src/libexpr/parser.cc @@ -0,0 +1,332 @@ +#include "libexpr/parser.hh" + +#include <fcntl.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> + +#include "libexpr/eval.hh" +#include "libstore/download.hh" +#include "libstore/store-api.hh" + +namespace nix { + +void addAttr(ExprAttrs* attrs, AttrPath& attrPath, Expr* e, const Pos& pos) { + AttrPath::iterator i; + // All attrpaths have at least one attr + assert(!attrPath.empty()); + // Checking attrPath validity. + // =========================== + for (i = attrPath.begin(); i + 1 < attrPath.end(); i++) { + if (const auto* sym = std::get_if<Symbol>(&(*i)); sym && sym->set()) { + ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(*sym); + if (j != attrs->attrs.end()) { + if (!j->second.inherited) { + ExprAttrs* attrs2 = dynamic_cast<ExprAttrs*>(j->second.e); + if (!attrs2) { + dupAttr(attrPath, pos, j->second.pos); + } + attrs = attrs2; + } else { + dupAttr(attrPath, pos, j->second.pos); + } + } else { + ExprAttrs* nested = new ExprAttrs; + attrs->attrs[*sym] = ExprAttrs::AttrDef(nested, pos); + attrs = nested; + } + } else { + // Yes, this code does not handle all conditions + // exhaustively. We use std::get to throw if the condition + // that isn't covered happens, which is potentially a + // behaviour change from the previous default constructed + // Symbol. It should alert us about anything untoward going + // on here. + auto* expr = std::get<Expr*>(*i); + + ExprAttrs* nested = new ExprAttrs; + attrs->dynamicAttrs.push_back( + ExprAttrs::DynamicAttrDef(expr, nested, pos)); + attrs = nested; + } + } + // Expr insertion. + // ========================== + if (auto* sym = std::get_if<Symbol>(&(*i)); sym && sym->set()) { + ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(*sym); + if (j != attrs->attrs.end()) { + // This attr path is already defined. However, if both + // e and the expr pointed by the attr path are two attribute sets, + // we want to merge them. + // Otherwise, throw an error. + auto ae = dynamic_cast<ExprAttrs*>(e); + auto jAttrs = dynamic_cast<ExprAttrs*>(j->second.e); + if (jAttrs && ae) { + for (auto& ad : ae->attrs) { + auto j2 = jAttrs->attrs.find(ad.first); + if (j2 != + jAttrs->attrs.end()) { // Attr already defined in iAttrs, error. + dupAttr(ad.first, j2->second.pos, ad.second.pos); + } + jAttrs->attrs[ad.first] = ad.second; + } + } else { + dupAttr(attrPath, pos, j->second.pos); + } + } else { + // This attr path is not defined. Let's create it. + attrs->attrs[*sym] = ExprAttrs::AttrDef(e, pos); + } + } else { + // Same caveat as the identical line above. + auto* expr = std::get<Expr*>(*i); + attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(expr, e, pos)); + } +} + +void addFormal(const Pos& pos, Formals* formals, const Formal& formal) { + if (formals->argNames.find(formal.name) != formals->argNames.end()) { + throw ParseError(format("duplicate formal function argument '%1%' at %2%") % + formal.name % pos); + } + formals->formals.push_front(formal); + formals->argNames.insert(formal.name); +} + +Expr* stripIndentation(const Pos& pos, SymbolTable& symbols, VectorExprs& es) { + if (es.empty()) { + return new ExprString(symbols.Create("")); + } + + /* Figure out the minimum indentation. Note that by design + whitespace-only final lines are not taken into account. (So + the " " in "\n ''" is ignored, but the " " in "\n foo''" is.) */ + bool atStartOfLine = true; /* = seen only whitespace in the current line */ + size_t minIndent = 1000000; + size_t curIndent = 0; + for (auto& i : es) { + ExprIndStr* e = dynamic_cast<ExprIndStr*>(i); + if (!e) { + /* Anti-quotations end the current start-of-line whitespace. */ + if (atStartOfLine) { + atStartOfLine = false; + if (curIndent < minIndent) { + minIndent = curIndent; + } + } + continue; + } + for (size_t j = 0; j < e->s.size(); ++j) { + if (atStartOfLine) { + if (e->s[j] == ' ') { + curIndent++; + } else if (e->s[j] == '\n') { + /* Empty line, doesn't influence minimum + indentation. */ + curIndent = 0; + } else { + atStartOfLine = false; + if (curIndent < minIndent) { + minIndent = curIndent; + } + } + } else if (e->s[j] == '\n') { + atStartOfLine = true; + curIndent = 0; + } + } + } + + /* Strip spaces from each line. */ + VectorExprs* es2 = new VectorExprs; + atStartOfLine = true; + size_t curDropped = 0; + size_t n = es.size(); + for (VectorExprs::iterator i = es.begin(); i != es.end(); ++i, --n) { + ExprIndStr* e = dynamic_cast<ExprIndStr*>(*i); + if (!e) { + atStartOfLine = false; + curDropped = 0; + es2->push_back(*i); + continue; + } + + std::string s2; + for (size_t j = 0; j < e->s.size(); ++j) { + if (atStartOfLine) { + if (e->s[j] == ' ') { + if (curDropped++ >= minIndent) { + s2 += e->s[j]; + } + } else if (e->s[j] == '\n') { + curDropped = 0; + s2 += e->s[j]; + } else { + atStartOfLine = false; + curDropped = 0; + s2 += e->s[j]; + } + } else { + s2 += e->s[j]; + if (e->s[j] == '\n') { + atStartOfLine = true; + } + } + } + + /* Remove the last line if it is empty and consists only of + spaces. */ + if (n == 1) { + std::string::size_type p = s2.find_last_of('\n'); + if (p != std::string::npos && + s2.find_first_not_of(' ', p + 1) == std::string::npos) { + s2 = std::string(s2, 0, p + 1); + } + } + + es2->push_back(new ExprString(symbols.Create(s2))); + } + + /* If this is a single string, then don't do a concatenation. */ + return es2->size() == 1 && dynamic_cast<ExprString*>((*es2)[0]) + ? (*es2)[0] + : new ExprConcatStrings(pos, true, es2); +} + +Path resolveExprPath(Path path) { + assert(path[0] == '/'); + + /* If `path' is a symlink, follow it. This is so that relative + path references work. */ + struct stat st; + while (true) { + if (lstat(path.c_str(), &st)) { + throw SysError(format("getting status of '%1%'") % path); + } + if (!S_ISLNK(st.st_mode)) { + break; + } + path = absPath(readLink(path), dirOf(path)); + } + + /* If `path' refers to a directory, append `/default.nix'. */ + if (S_ISDIR(st.st_mode)) { + path = canonPath(path + "/default.nix"); + } + + return path; +} + +// These methods are actually declared in eval.hh, and were - for some +// reason - previously implemented in parser.y. + +Expr* EvalState::parseExprFromFile(const Path& path) { + return parseExprFromFile(path, staticBaseEnv); +} + +Expr* EvalState::parseExprFromFile(const Path& path, StaticEnv& staticEnv) { + return parse(readFile(path).c_str(), path, dirOf(path), staticEnv); +} + +Expr* EvalState::parseExprFromString(const std::string& s, const Path& basePath, + StaticEnv& staticEnv) { + return parse(s.c_str(), "(std::string)", basePath, staticEnv); +} + +Expr* EvalState::parseExprFromString(const std::string& s, + const Path& basePath) { + return parseExprFromString(s, basePath, staticBaseEnv); +} + +Expr* EvalState::parseStdin() { + // Activity act(*logger, lvlTalkative, format("parsing standard input")); + return parseExprFromString(drainFD(0), absPath(".")); +} + +void EvalState::addToSearchPath(const std::string& s) { + size_t pos = s.find('='); + std::string prefix; + Path path; + if (pos == std::string::npos) { + path = s; + } else { + prefix = std::string(s, 0, pos); + path = std::string(s, pos + 1); + } + + searchPath.emplace_back(prefix, path); +} + +Path EvalState::findFile(const std::string& path) { + return findFile(searchPath, path); +} + +Path EvalState::findFile(SearchPath& searchPath, const std::string& path, + const Pos& pos) { + for (auto& i : searchPath) { + std::string suffix; + if (i.first.empty()) { + suffix = "/" + path; + } else { + auto s = i.first.size(); + if (path.compare(0, s, i.first) != 0 || + (path.size() > s && path[s] != '/')) { + continue; + } + suffix = path.size() == s ? "" : "/" + std::string(path, s); + } + auto r = resolveSearchPathElem(i); + if (!r.first) { + continue; + } + Path res = r.second + suffix; + if (pathExists(res)) { + return canonPath(res); + } + } + format f = format( + "file '%1%' was not found in the Nix search path (add it using $NIX_PATH " + "or -I)" + + std::string(pos ? ", at %2%" : "")); + f.exceptions(boost::io::all_error_bits ^ boost::io::too_many_args_bit); + throw ThrownError(f % path % pos); +} + +std::pair<bool, std::string> EvalState::resolveSearchPathElem( + const SearchPathElem& elem) { + auto i = searchPathResolved.find(elem.second); + if (i != searchPathResolved.end()) { + return i->second; + } + + std::pair<bool, std::string> res; + + if (isUri(elem.second)) { + try { + CachedDownloadRequest request(elem.second); + request.unpack = true; + res = {true, getDownloader()->downloadCached(store, request).path}; + } catch (DownloadError& e) { + LOG(WARNING) << "Nix search path entry '" << elem.second + << "' cannot be downloaded, ignoring"; + res = {false, ""}; + } + } else { + auto path = absPath(elem.second); + if (pathExists(path)) { + res = {true, path}; + } else { + LOG(WARNING) << "Nix search path entry '" << elem.second + << "' does not exist, ignoring"; + res = {false, ""}; + } + } + + VLOG(2) << "resolved search path element '" << elem.second << "' to '" + << res.second << "'"; + + searchPathResolved[elem.second] = res; + return res; +} + +} // namespace nix |