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Merge pull request #9776 from pennae/parser-refactor

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Refactor the parser somewhat
This commit is contained in:
John Ericson 2024-01-26 23:56:48 -05:00 committed by GitHub
commit b83a2fb6dd
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7 changed files with 574 additions and 544 deletions
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190
src/libexpr/eval.cc
View file

@ -21,6 +21,9 @@
#include "gc-small-vector.hh"
#include "url.hh"
#include "fetch-to-store.hh"
#include "tarball.hh"
#include "flake/flakeref.hh"
#include "parser-tab.hh"
#include <algorithm>
#include <chrono>
@ -417,6 +420,16 @@ EvalState::EvalState(
, sPath(symbols.create("path"))
, sPrefix(symbols.create("prefix"))
, sOutputSpecified(symbols.create("outputSpecified"))
, exprSymbols{
.sub = symbols.create("__sub"),
.lessThan = symbols.create("__lessThan"),
.mul = symbols.create("__mul"),
.div = symbols.create("__div"),
.or_ = symbols.create("or"),
.findFile = symbols.create("__findFile"),
.nixPath = symbols.create("__nixPath"),
.body = symbols.create("body"),
}
, repair(NoRepair)
, emptyBindings(0)
, rootFS(
@ -2666,6 +2679,183 @@ void EvalState::printStatistics()
}
SourcePath resolveExprPath(SourcePath path)
{
unsigned int followCount = 0, maxFollow = 1024;
/* If `path' is a symlink, follow it. This is so that relative
path references work. */
while (!path.path.isRoot()) {
// Basic cycle/depth limit to avoid infinite loops.
if (++followCount >= maxFollow)
throw Error("too many symbolic links encountered while traversing the path '%s'", path);
auto p = path.parent().resolveSymlinks() + path.baseName();
if (p.lstat().type != InputAccessor::tSymlink) break;
path = {path.accessor, CanonPath(p.readLink(), path.path.parent().value_or(CanonPath::root))};
}
/* If `path' refers to a directory, append `/default.nix'. */
if (path.resolveSymlinks().lstat().type == InputAccessor::tDirectory)
return path + "default.nix";
return path;
}
Expr * EvalState::parseExprFromFile(const SourcePath & path)
{
return parseExprFromFile(path, staticBaseEnv);
}
Expr * EvalState::parseExprFromFile(const SourcePath & path, std::shared_ptr<StaticEnv> & staticEnv)
{
auto buffer = path.resolveSymlinks().readFile();
// readFile hopefully have left some extra space for terminators
buffer.append("\0\0", 2);
return parse(buffer.data(), buffer.size(), Pos::Origin(path), path.parent(), staticEnv);
}
Expr * EvalState::parseExprFromString(std::string s_, const SourcePath & basePath, std::shared_ptr<StaticEnv> & staticEnv)
{
auto s = make_ref<std::string>(std::move(s_));
s->append("\0\0", 2);
return parse(s->data(), s->size(), Pos::String{.source = s}, basePath, staticEnv);
}
Expr * EvalState::parseExprFromString(std::string s, const SourcePath & basePath)
{
return parseExprFromString(std::move(s), basePath, staticBaseEnv);
}
Expr * EvalState::parseStdin()
{
//Activity act(*logger, lvlTalkative, "parsing standard input");
auto buffer = drainFD(0);
// drainFD should have left some extra space for terminators
buffer.append("\0\0", 2);
auto s = make_ref<std::string>(std::move(buffer));
return parse(s->data(), s->size(), Pos::Stdin{.source = s}, rootPath(CanonPath::fromCwd()), staticBaseEnv);
}
SourcePath EvalState::findFile(const std::string_view path)
{
return findFile(searchPath, path);
}
SourcePath EvalState::findFile(const SearchPath & searchPath, const std::string_view path, const PosIdx pos)
{
for (auto & i : searchPath.elements) {
auto suffixOpt = i.prefix.suffixIfPotentialMatch(path);
if (!suffixOpt) continue;
auto suffix = *suffixOpt;
auto rOpt = resolveSearchPathPath(i.path);
if (!rOpt) continue;
auto r = *rOpt;
Path res = suffix == "" ? r : concatStrings(r, "/", suffix);
if (pathExists(res)) return rootPath(CanonPath(canonPath(res)));
}
if (hasPrefix(path, "nix/"))
return {corepkgsFS, CanonPath(path.substr(3))};
debugThrow(ThrownError({
.msg = hintfmt(evalSettings.pureEval
? "cannot look up '<%s>' in pure evaluation mode (use '--impure' to override)"
: "file '%s' was not found in the Nix search path (add it using $NIX_PATH or -I)",
path),
.errPos = positions[pos]
}), 0, 0);
}
std::optional<std::string> EvalState::resolveSearchPathPath(const SearchPath::Path & value0, bool initAccessControl)
{
auto & value = value0.s;
auto i = searchPathResolved.find(value);
if (i != searchPathResolved.end()) return i->second;
std::optional<std::string> res;
if (EvalSettings::isPseudoUrl(value)) {
try {
auto storePath = fetchers::downloadTarball(
store, EvalSettings::resolvePseudoUrl(value), "source", false).storePath;
res = { store->toRealPath(storePath) };
} catch (FileTransferError & e) {
logWarning({
.msg = hintfmt("Nix search path entry '%1%' cannot be downloaded, ignoring", value)
});
}
}
else if (hasPrefix(value, "flake:")) {
experimentalFeatureSettings.require(Xp::Flakes);
auto flakeRef = parseFlakeRef(value.substr(6), {}, true, false);
debug("fetching flake search path element '%s''", value);
auto storePath = flakeRef.resolve(store).fetchTree(store).first;
res = { store->toRealPath(storePath) };
}
else {
auto path = absPath(value);
/* Allow access to paths in the search path. */
if (initAccessControl) {
allowPath(path);
if (store->isInStore(path)) {
try {
StorePathSet closure;
store->computeFSClosure(store->toStorePath(path).first, closure);
for (auto & p : closure)
allowPath(p);
} catch (InvalidPath &) { }
}
}
if (pathExists(path))
res = { path };
else {
logWarning({
.msg = hintfmt("Nix search path entry '%1%' does not exist, ignoring", value)
});
res = std::nullopt;
}
}
if (res)
debug("resolved search path element '%s' to '%s'", value, *res);
else
debug("failed to resolve search path element '%s'", value);
searchPathResolved.emplace(value, res);
return res;
}
Expr * EvalState::parse(
char * text,
size_t length,
Pos::Origin origin,
const SourcePath & basePath,
std::shared_ptr<StaticEnv> & staticEnv)
{
auto result = parseExprFromBuf(text, length, origin, basePath, symbols, positions, rootFS, exprSymbols);
result->bindVars(*this, staticEnv);
return result;
}
std::string ExternalValueBase::coerceToString(const Pos & pos, NixStringContext & context, bool copyMore, bool copyToStore) const
{
throw TypeError({

2
src/libexpr/eval.hh
View file

@ -207,6 +207,8 @@ public:
sPrefix,
sOutputSpecified;
const Expr::AstSymbols exprSymbols;
/**
* If set, force copying files to the Nix store even if they
* already exist there.

17
src/libexpr/lexer.l
View file

@ -29,12 +29,7 @@ using namespace nix;
namespace nix {
static inline PosIdx makeCurPos(const YYLTYPE & loc, ParseData * data)
{
return data->state.positions.add(data->origin, loc.first_line, loc.first_column);
}
#define CUR_POS makeCurPos(*yylloc, data)
#define CUR_POS state->at(*yylloc)
static void initLoc(YYLTYPE * loc)
{
@ -153,7 +148,7 @@ or { return OR_KW; }
} catch (const boost::bad_lexical_cast &) {
throw ParseError({
.msg = hintfmt("invalid integer '%1%'", yytext),
.errPos = data->state.positions[CUR_POS],
.errPos = state->positions[CUR_POS],
});
}
return INT_LIT;
@ -163,7 +158,7 @@ or { return OR_KW; }
if (errno != 0)
throw ParseError({
.msg = hintfmt("invalid float '%1%'", yytext),
.errPos = data->state.positions[CUR_POS],
.errPos = state->positions[CUR_POS],
});
return FLOAT_LIT;
}
@ -186,7 +181,7 @@ or { return OR_KW; }
/* It is impossible to match strings ending with '$' with one
regex because trailing contexts are only valid at the end
of a rule. (A sane but undocumented limitation.) */
yylval->str = unescapeStr(data->symbols, yytext, yyleng);
yylval->str = unescapeStr(state->symbols, yytext, yyleng);
return STR;
}
<STRING>\$\{ { PUSH_STATE(DEFAULT); return DOLLAR_CURLY; }
@ -214,7 +209,7 @@ or { return OR_KW; }
return IND_STR;
}
<IND_STRING>\'\'\\{ANY} {
yylval->str = unescapeStr(data->symbols, yytext + 2, yyleng - 2);
yylval->str = unescapeStr(state->symbols, yytext + 2, yyleng - 2);
return IND_STR;
}
<IND_STRING>\$\{ { PUSH_STATE(DEFAULT); return DOLLAR_CURLY; }
@ -292,7 +287,7 @@ or { return OR_KW; }
<INPATH_SLASH><<EOF>> {
throw ParseError({
.msg = hintfmt("path has a trailing slash"),
.errPos = data->state.positions[CUR_POS],
.errPos = state->positions[CUR_POS],
});
}

2
src/libexpr/nixexpr.cc
View file

@ -9,6 +9,8 @@
namespace nix {
unsigned long Expr::nrExprs = 0;
ExprBlackHole eBlackHole;
// FIXME: remove, because *symbols* are abstract and do not have a single

5
src/libexpr/nixexpr.hh
View file

@ -140,6 +140,11 @@ std::string showAttrPath(const SymbolTable & symbols, const AttrPath & attrPath)
struct Expr
{
struct AstSymbols {
Symbol sub, lessThan, mul, div, or_, findFile, nixPath, body;
};
static unsigned long nrExprs;
Expr() {
nrExprs++;

271
src/libexpr/parser-state.hh Normal file
View file

@ -0,0 +1,271 @@
#pragma once
///@file
#include "eval.hh"
namespace nix {
/**
* @note Storing a C-style `char *` and `size_t` allows us to avoid
* having to define the special members that using string_view here
* would implicitly delete.
*/
struct StringToken
{
const char * p;
size_t l;
bool hasIndentation;
operator std::string_view() const { return {p, l}; }
};
struct ParserLocation
{
int first_line, first_column;
int last_line, last_column;
// backup to recover from yyless(0)
int stashed_first_line, stashed_first_column;
int stashed_last_line, stashed_last_column;
void stash() {
stashed_first_line = first_line;
stashed_first_column = first_column;
stashed_last_line = last_line;
stashed_last_column = last_column;
}
void unstash() {
first_line = stashed_first_line;
first_column = stashed_first_column;
last_line = stashed_last_line;
last_column = stashed_last_column;
}
};
struct ParserState
{
SymbolTable & symbols;
PosTable & positions;
Expr * result;
SourcePath basePath;
PosTable::Origin origin;
const ref<InputAccessor> rootFS;
const Expr::AstSymbols & s;
void dupAttr(const AttrPath & attrPath, const PosIdx pos, const PosIdx prevPos);
void dupAttr(Symbol attr, const PosIdx pos, const PosIdx prevPos);
void addAttr(ExprAttrs * attrs, AttrPath && attrPath, Expr * e, const PosIdx pos);
Formals * validateFormals(Formals * formals, PosIdx pos = noPos, Symbol arg = {});
Expr * stripIndentation(const PosIdx pos,
std::vector<std::pair<PosIdx, std::variant<Expr *, StringToken>>> && es);
PosIdx at(const ParserLocation & loc);
};
inline void ParserState::dupAttr(const AttrPath & attrPath, const PosIdx pos, const PosIdx prevPos)
{
throw ParseError({
.msg = hintfmt("attribute '%1%' already defined at %2%",
showAttrPath(symbols, attrPath), positions[prevPos]),
.errPos = positions[pos]
});
}
inline void ParserState::dupAttr(Symbol attr, const PosIdx pos, const PosIdx prevPos)
{
throw ParseError({
.msg = hintfmt("attribute '%1%' already defined at %2%", symbols[attr], positions[prevPos]),
.errPos = positions[pos]
});
}
inline void ParserState::addAttr(ExprAttrs * attrs, AttrPath && attrPath, Expr * e, const PosIdx 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 (i->symbol) {
ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol);
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[i->symbol] = ExprAttrs::AttrDef(nested, pos);
attrs = nested;
}
} else {
ExprAttrs *nested = new ExprAttrs;
attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, nested, pos));
attrs = nested;
}
}
// Expr insertion.
// ==========================
if (i->symbol) {
ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol);
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.emplace(ad.first, ad.second);
}
jAttrs->dynamicAttrs.insert(jAttrs->dynamicAttrs.end(), ae->dynamicAttrs.begin(), ae->dynamicAttrs.end());
} else {
dupAttr(attrPath, pos, j->second.pos);
}
} else {
// This attr path is not defined. Let's create it.
attrs->attrs.emplace(i->symbol, ExprAttrs::AttrDef(e, pos));
e->setName(i->symbol);
}
} else {
attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, e, pos));
}
}
inline Formals * ParserState::validateFormals(Formals * formals, PosIdx pos, Symbol arg)
{
std::sort(formals->formals.begin(), formals->formals.end(),
[] (const auto & a, const auto & b) {
return std::tie(a.name, a.pos) < std::tie(b.name, b.pos);
});
std::optional<std::pair<Symbol, PosIdx>> duplicate;
for (size_t i = 0; i + 1 < formals->formals.size(); i++) {
if (formals->formals[i].name != formals->formals[i + 1].name)
continue;
std::pair thisDup{formals->formals[i].name, formals->formals[i + 1].pos};
duplicate = std::min(thisDup, duplicate.value_or(thisDup));
}
if (duplicate)
throw ParseError({
.msg = hintfmt("duplicate formal function argument '%1%'", symbols[duplicate->first]),
.errPos = positions[duplicate->second]
});
if (arg && formals->has(arg))
throw ParseError({
.msg = hintfmt("duplicate formal function argument '%1%'", symbols[arg]),
.errPos = positions[pos]
});
return formals;
}
inline Expr * ParserState::stripIndentation(const PosIdx pos,
std::vector<std::pair<PosIdx, std::variant<Expr *, StringToken>>> && es)
{
if (es.empty()) return new ExprString("");
/* 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_pos, i] : es) {
auto * str = std::get_if<StringToken>(&i);
if (!str || !str->hasIndentation) {
/* Anti-quotations and escaped characters end the current start-of-line whitespace. */
if (atStartOfLine) {
atStartOfLine = false;
if (curIndent < minIndent) minIndent = curIndent;
}
continue;
}
for (size_t j = 0; j < str->l; ++j) {
if (atStartOfLine) {
if (str->p[j] == ' ')
curIndent++;
else if (str->p[j] == '\n') {
/* Empty line, doesn't influence minimum
indentation. */
curIndent = 0;
} else {
atStartOfLine = false;
if (curIndent < minIndent) minIndent = curIndent;
}
} else if (str->p[j] == '\n') {
atStartOfLine = true;
curIndent = 0;
}
}
}
/* Strip spaces from each line. */
auto * es2 = new std::vector<std::pair<PosIdx, Expr *>>;
atStartOfLine = true;
size_t curDropped = 0;
size_t n = es.size();
auto i = es.begin();
const auto trimExpr = [&] (Expr * e) {
atStartOfLine = false;
curDropped = 0;
es2->emplace_back(i->first, e);
};
const auto trimString = [&] (const StringToken & t) {
std::string s2;
for (size_t j = 0; j < t.l; ++j) {
if (atStartOfLine) {
if (t.p[j] == ' ') {
if (curDropped++ >= minIndent)
s2 += t.p[j];
}
else if (t.p[j] == '\n') {
curDropped = 0;
s2 += t.p[j];
} else {
atStartOfLine = false;
curDropped = 0;
s2 += t.p[j];
}
} else {
s2 += t.p[j];
if (t.p[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->emplace_back(i->first, new ExprString(std::move(s2)));
};
for (; i != es.end(); ++i, --n) {
std::visit(overloaded { trimExpr, trimString }, i->second);
}
/* If this is a single string, then don't do a concatenation. */
if (es2->size() == 1 && dynamic_cast<ExprString *>((*es2)[0].second)) {
auto *const result = (*es2)[0].second;
delete es2;
return result;
}
return new ExprConcatStrings(pos, true, es2);
}
inline PosIdx ParserState::at(const ParserLocation & loc)
{
return positions.add(origin, loc.first_line, loc.first_column);
}
}

631
src/libexpr/parser.y
View file

@ -5,9 +5,9 @@
%defines
/* %no-lines */
%parse-param { void * scanner }
%parse-param { nix::ParseData * data }
%parse-param { nix::ParserState * state }
%lex-param { void * scanner }
%lex-param { nix::ParseData * data }
%lex-param { nix::ParserState * state }
%expect 1
%expect-rr 1
@ -18,6 +18,7 @@
#include <variant>
#include "finally.hh"
#include "util.hh"
#include "users.hh"
@ -25,63 +26,26 @@
#include "eval.hh"
#include "eval-settings.hh"
#include "globals.hh"
#include "parser-state.hh"
#define YYLTYPE ::nix::ParserLocation
#define YY_DECL int yylex \
(YYSTYPE * yylval_param, YYLTYPE * yylloc_param, yyscan_t yyscanner, nix::ParserState * state)
namespace nix {
#define YYLTYPE ::nix::ParserLocation
struct ParserLocation
{
int first_line, first_column;
int last_line, last_column;
// backup to recover from yyless(0)
int stashed_first_line, stashed_first_column;
int stashed_last_line, stashed_last_column;
void stash() {
stashed_first_line = first_line;
stashed_first_column = first_column;
stashed_last_line = last_line;
stashed_last_column = last_column;
}
void unstash() {
first_line = stashed_first_line;
first_column = stashed_first_column;
last_line = stashed_last_line;
last_column = stashed_last_column;
}
};
struct ParseData
{
EvalState & state;
SymbolTable & symbols;
Expr * result;
SourcePath basePath;
PosTable::Origin origin;
std::optional<ErrorInfo> error;
};
struct ParserFormals {
std::vector<Formal> formals;
bool ellipsis = false;
};
Expr * parseExprFromBuf(
char * text,
size_t length,
Pos::Origin origin,
const SourcePath & basePath,
SymbolTable & symbols,
PosTable & positions,
const ref<InputAccessor> rootFS,
const Expr::AstSymbols & astSymbols);
}
// using C a struct allows us to avoid having to define the special
// members that using string_view here would implicitly delete.
struct StringToken {
const char * p;
size_t l;
bool hasIndentation;
operator std::string_view() const { return {p, l}; }
};
#define YY_DECL int yylex \
(YYSTYPE * yylval_param, YYLTYPE * yylloc_param, yyscan_t yyscanner, nix::ParseData * data)
#endif
}
@ -95,240 +59,15 @@ YY_DECL;
using namespace nix;
namespace nix {
#define CUR_POS state->at(*yylocp)
static void dupAttr(const EvalState & state, const AttrPath & attrPath, const PosIdx pos, const PosIdx prevPos)
void yyerror(YYLTYPE * loc, yyscan_t scanner, ParserState * state, const char * error)
{
throw ParseError({
.msg = hintfmt("attribute '%1%' already defined at %2%",
showAttrPath(state.symbols, attrPath), state.positions[prevPos]),
.errPos = state.positions[pos]
});
}
static void dupAttr(const EvalState & state, Symbol attr, const PosIdx pos, const PosIdx prevPos)
{
throw ParseError({
.msg = hintfmt("attribute '%1%' already defined at %2%", state.symbols[attr], state.positions[prevPos]),
.errPos = state.positions[pos]
});
}
static void addAttr(ExprAttrs * attrs, AttrPath && attrPath,
Expr * e, const PosIdx pos, const nix::EvalState & state)
{
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 (i->symbol) {
ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol);
if (j != attrs->attrs.end()) {
if (!j->second.inherited) {
ExprAttrs * attrs2 = dynamic_cast<ExprAttrs *>(j->second.e);
if (!attrs2) dupAttr(state, attrPath, pos, j->second.pos);
attrs = attrs2;
} else
dupAttr(state, attrPath, pos, j->second.pos);
} else {
ExprAttrs * nested = new ExprAttrs;
attrs->attrs[i->symbol] = ExprAttrs::AttrDef(nested, pos);
attrs = nested;
}
} else {
ExprAttrs *nested = new ExprAttrs;
attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, nested, pos));
attrs = nested;
}
}
// Expr insertion.
// ==========================
if (i->symbol) {
ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol);
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(state, ad.first, j2->second.pos, ad.second.pos);
jAttrs->attrs.emplace(ad.first, ad.second);
}
jAttrs->dynamicAttrs.insert(jAttrs->dynamicAttrs.end(), ae->dynamicAttrs.begin(), ae->dynamicAttrs.end());
} else {
dupAttr(state, attrPath, pos, j->second.pos);
}
} else {
// This attr path is not defined. Let's create it.
attrs->attrs.emplace(i->symbol, ExprAttrs::AttrDef(e, pos));
e->setName(i->symbol);
}
} else {
attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, e, pos));
}
}
static Formals * toFormals(ParseData & data, ParserFormals * formals,
PosIdx pos = noPos, Symbol arg = {})
{
std::sort(formals->formals.begin(), formals->formals.end(),
[] (const auto & a, const auto & b) {
return std::tie(a.name, a.pos) < std::tie(b.name, b.pos);
});
std::optional<std::pair<Symbol, PosIdx>> duplicate;
for (size_t i = 0; i + 1 < formals->formals.size(); i++) {
if (formals->formals[i].name != formals->formals[i + 1].name)
continue;
std::pair thisDup{formals->formals[i].name, formals->formals[i + 1].pos};
duplicate = std::min(thisDup, duplicate.value_or(thisDup));
}
if (duplicate)
throw ParseError({
.msg = hintfmt("duplicate formal function argument '%1%'", data.symbols[duplicate->first]),
.errPos = data.state.positions[duplicate->second]
});
Formals result;
result.ellipsis = formals->ellipsis;
result.formals = std::move(formals->formals);
if (arg && result.has(arg))
throw ParseError({
.msg = hintfmt("duplicate formal function argument '%1%'", data.symbols[arg]),
.errPos = data.state.positions[pos]
});
delete formals;
return new Formals(std::move(result));
}
static Expr * stripIndentation(const PosIdx pos, SymbolTable & symbols,
std::vector<std::pair<PosIdx, std::variant<Expr *, StringToken>>> && es)
{
if (es.empty()) return new ExprString("");
/* 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_pos, i] : es) {
auto * str = std::get_if<StringToken>(&i);
if (!str || !str->hasIndentation) {
/* Anti-quotations and escaped characters end the current start-of-line whitespace. */
if (atStartOfLine) {
atStartOfLine = false;
if (curIndent < minIndent) minIndent = curIndent;
}
continue;
}
for (size_t j = 0; j < str->l; ++j) {
if (atStartOfLine) {
if (str->p[j] == ' ')
curIndent++;
else if (str->p[j] == '\n') {
/* Empty line, doesn't influence minimum
indentation. */
curIndent = 0;
} else {
atStartOfLine = false;
if (curIndent < minIndent) minIndent = curIndent;
}
} else if (str->p[j] == '\n') {
atStartOfLine = true;
curIndent = 0;
}
}
}
/* Strip spaces from each line. */
auto * es2 = new std::vector<std::pair<PosIdx, Expr *>>;
atStartOfLine = true;
size_t curDropped = 0;
size_t n = es.size();
auto i = es.begin();
const auto trimExpr = [&] (Expr * e) {
atStartOfLine = false;
curDropped = 0;
es2->emplace_back(i->first, e);
};
const auto trimString = [&] (const StringToken & t) {
std::string s2;
for (size_t j = 0; j < t.l; ++j) {
if (atStartOfLine) {
if (t.p[j] == ' ') {
if (curDropped++ >= minIndent)
s2 += t.p[j];
}
else if (t.p[j] == '\n') {
curDropped = 0;
s2 += t.p[j];
} else {
atStartOfLine = false;
curDropped = 0;
s2 += t.p[j];
}
} else {
s2 += t.p[j];
if (t.p[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->emplace_back(i->first, new ExprString(std::move(s2)));
};
for (; i != es.end(); ++i, --n) {
std::visit(overloaded { trimExpr, trimString }, i->second);
}
/* If this is a single string, then don't do a concatenation. */
if (es2->size() == 1 && dynamic_cast<ExprString *>((*es2)[0].second)) {
auto *const result = (*es2)[0].second;
delete es2;
return result;
}
return new ExprConcatStrings(pos, true, es2);
}
static inline PosIdx makeCurPos(const YYLTYPE & loc, ParseData * data)
{
return data->state.positions.add(data->origin, loc.first_line, loc.first_column);
}
#define CUR_POS makeCurPos(*yylocp, data)
}
void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * error)
{
data->error = {
.msg = hintfmt(error),
.errPos = data->state.positions[makeCurPos(*loc, data)]
};
.errPos = state->positions[state->at(*loc)]
});
}
@ -339,17 +78,17 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * err
nix::Expr * e;
nix::ExprList * list;
nix::ExprAttrs * attrs;
nix::ParserFormals * formals;
nix::Formals * formals;
nix::Formal * formal;
nix::NixInt n;
nix::NixFloat nf;
StringToken id; // !!! -> Symbol
StringToken path;
StringToken uri;
StringToken str;
nix::StringToken id; // !!! -> Symbol
nix::StringToken path;
nix::StringToken uri;
nix::StringToken str;
std::vector<nix::AttrName> * attrNames;
std::vector<std::pair<nix::PosIdx, nix::Expr *>> * string_parts;
std::vector<std::pair<nix::PosIdx, std::variant<nix::Expr *, StringToken>>> * ind_string_parts;
std::vector<std::pair<nix::PosIdx, std::variant<nix::Expr *, nix::StringToken>>> * ind_string_parts;
}
%type <e> start expr expr_function expr_if expr_op
@ -389,24 +128,24 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * err
%%
start: expr { data->result = $1; };
start: expr { state->result = $1; };
expr: expr_function;
expr_function
: ID ':' expr_function
{ $$ = new ExprLambda(CUR_POS, data->symbols.create($1), 0, $3); }
{ $$ = new ExprLambda(CUR_POS, state->symbols.create($1), 0, $3); }
| '{' formals '}' ':' expr_function
{ $$ = new ExprLambda(CUR_POS, toFormals(*data, $2), $5); }
{ $$ = new ExprLambda(CUR_POS, state->validateFormals($2), $5); }
| '{' formals '}' '@' ID ':' expr_function
{
auto arg = data->symbols.create($5);
$$ = new ExprLambda(CUR_POS, arg, toFormals(*data, $2, CUR_POS, arg), $7);
auto arg = state->symbols.create($5);
$$ = new ExprLambda(CUR_POS, arg, state->validateFormals($2, CUR_POS, arg), $7);
}
| ID '@' '{' formals '}' ':' expr_function
{
auto arg = data->symbols.create($1);
$$ = new ExprLambda(CUR_POS, arg, toFormals(*data, $4, CUR_POS, arg), $7);
auto arg = state->symbols.create($1);
$$ = new ExprLambda(CUR_POS, arg, state->validateFormals($4, CUR_POS, arg), $7);
}
| ASSERT expr ';' expr_function
{ $$ = new ExprAssert(CUR_POS, $2, $4); }
@ -416,7 +155,7 @@ expr_function
{ if (!$2->dynamicAttrs.empty())
throw ParseError({
.msg = hintfmt("dynamic attributes not allowed in let"),
.errPos = data->state.positions[CUR_POS]
.errPos = state->positions[CUR_POS]
});
$$ = new ExprLet($2, $4);
}
@ -430,24 +169,24 @@ expr_if
expr_op
: '!' expr_op %prec NOT { $$ = new ExprOpNot($2); }
| '-' expr_op %prec NEGATE { $$ = new ExprCall(CUR_POS, new ExprVar(data->symbols.create("__sub")), {new ExprInt(0), $2}); }
| '-' expr_op %prec NEGATE { $$ = new ExprCall(CUR_POS, new ExprVar(state->s.sub), {new ExprInt(0), $2}); }
| expr_op EQ expr_op { $$ = new ExprOpEq($1, $3); }
| expr_op NEQ expr_op { $$ = new ExprOpNEq($1, $3); }
| expr_op '<' expr_op { $$ = new ExprCall(makeCurPos(@2, data), new ExprVar(data->symbols.create("__lessThan")), {$1, $3}); }
| expr_op LEQ expr_op { $$ = new ExprOpNot(new ExprCall(makeCurPos(@2, data), new ExprVar(data->symbols.create("__lessThan")), {$3, $1})); }
| expr_op '>' expr_op { $$ = new ExprCall(makeCurPos(@2, data), new ExprVar(data->symbols.create("__lessThan")), {$3, $1}); }
| expr_op GEQ expr_op { $$ = new ExprOpNot(new ExprCall(makeCurPos(@2, data), new ExprVar(data->symbols.create("__lessThan")), {$1, $3})); }
| expr_op AND expr_op { $$ = new ExprOpAnd(makeCurPos(@2, data), $1, $3); }
| expr_op OR expr_op { $$ = new ExprOpOr(makeCurPos(@2, data), $1, $3); }
| expr_op IMPL expr_op { $$ = new ExprOpImpl(makeCurPos(@2, data), $1, $3); }
| expr_op UPDATE expr_op { $$ = new ExprOpUpdate(makeCurPos(@2, data), $1, $3); }
| expr_op '<' expr_op { $$ = new ExprCall(state->at(@2), new ExprVar(state->s.lessThan), {$1, $3}); }
| expr_op LEQ expr_op { $$ = new ExprOpNot(new ExprCall(state->at(@2), new ExprVar(state->s.lessThan), {$3, $1})); }
| expr_op '>' expr_op { $$ = new ExprCall(state->at(@2), new ExprVar(state->s.lessThan), {$3, $1}); }
| expr_op GEQ expr_op { $$ = new ExprOpNot(new ExprCall(state->at(@2), new ExprVar(state->s.lessThan), {$1, $3})); }
| expr_op AND expr_op { $$ = new ExprOpAnd(state->at(@2), $1, $3); }
| expr_op OR expr_op { $$ = new ExprOpOr(state->at(@2), $1, $3); }
| expr_op IMPL expr_op { $$ = new ExprOpImpl(state->at(@2), $1, $3); }
| expr_op UPDATE expr_op { $$ = new ExprOpUpdate(state->at(@2), $1, $3); }
| expr_op '?' attrpath { $$ = new ExprOpHasAttr($1, std::move(*$3)); delete $3; }
| expr_op '+' expr_op
{ $$ = new ExprConcatStrings(makeCurPos(@2, data), false, new std::vector<std::pair<PosIdx, Expr *> >({{makeCurPos(@1, data), $1}, {makeCurPos(@3, data), $3}})); }
| expr_op '-' expr_op { $$ = new ExprCall(makeCurPos(@2, data), new ExprVar(data->symbols.create("__sub")), {$1, $3}); }
| expr_op '*' expr_op { $$ = new ExprCall(makeCurPos(@2, data), new ExprVar(data->symbols.create("__mul")), {$1, $3}); }
| expr_op '/' expr_op { $$ = new ExprCall(makeCurPos(@2, data), new ExprVar(data->symbols.create("__div")), {$1, $3}); }
| expr_op CONCAT expr_op { $$ = new ExprOpConcatLists(makeCurPos(@2, data), $1, $3); }
{ $$ = new ExprConcatStrings(state->at(@2), false, new std::vector<std::pair<PosIdx, Expr *> >({{state->at(@1), $1}, {state->at(@3), $3}})); }
| expr_op '-' expr_op { $$ = new ExprCall(state->at(@2), new ExprVar(state->s.sub), {$1, $3}); }
| expr_op '*' expr_op { $$ = new ExprCall(state->at(@2), new ExprVar(state->s.mul), {$1, $3}); }
| expr_op '/' expr_op { $$ = new ExprCall(state->at(@2), new ExprVar(state->s.div), {$1, $3}); }
| expr_op CONCAT expr_op { $$ = new ExprOpConcatLists(state->at(@2), $1, $3); }
| expr_app
;
@ -470,7 +209,7 @@ expr_select
| /* Backwards compatibility: because Nixpkgs has a rarely used
function named ‘or’, allow stuff like ‘map or [...]’. */
expr_simple OR_KW
{ $$ = new ExprCall(CUR_POS, $1, {new ExprVar(CUR_POS, data->symbols.create("or"))}); }
{ $$ = new ExprCall(CUR_POS, $1, {new ExprVar(CUR_POS, state->s.or_)}); }
| expr_simple
;
@ -480,25 +219,25 @@ expr_simple
if ($1.l == s.size() && strncmp($1.p, s.data(), s.size()) == 0)
$$ = new ExprPos(CUR_POS);
else
$$ = new ExprVar(CUR_POS, data->symbols.create($1));
$$ = new ExprVar(CUR_POS, state->symbols.create($1));
}
| INT_LIT { $$ = new ExprInt($1); }
| FLOAT_LIT { $$ = new ExprFloat($1); }
| '"' string_parts '"' { $$ = $2; }
| IND_STRING_OPEN ind_string_parts IND_STRING_CLOSE {
$$ = stripIndentation(CUR_POS, data->symbols, std::move(*$2));
$$ = state->stripIndentation(CUR_POS, std::move(*$2));
delete $2;
}
| path_start PATH_END
| path_start string_parts_interpolated PATH_END {
$2->insert($2->begin(), {makeCurPos(@1, data), $1});
$2->insert($2->begin(), {state->at(@1), $1});
$$ = new ExprConcatStrings(CUR_POS, false, $2);
}
| SPATH {
std::string path($1.p + 1, $1.l - 2);
$$ = new ExprCall(CUR_POS,
new ExprVar(data->symbols.create("__findFile")),
{new ExprVar(data->symbols.create("__nixPath")),
new ExprVar(state->s.findFile),
{new ExprVar(state->s.nixPath),
new ExprString(std::move(path))});
}
| URI {
@ -506,7 +245,7 @@ expr_simple
if (noURLLiterals)
throw ParseError({
.msg = hintfmt("URL literals are disabled"),
.errPos = data->state.positions[CUR_POS]
.errPos = state->positions[CUR_POS]
});
$$ = new ExprString(std::string($1));
}
@ -514,7 +253,7 @@ expr_simple
/* Let expressions `let {..., body = ...}' are just desugared
into `(rec {..., body = ...}).body'. */
| LET '{' binds '}'
{ $3->recursive = true; $$ = new ExprSelect(noPos, $3, data->symbols.create("body")); }
{ $3->recursive = true; $$ = new ExprSelect(noPos, $3, state->s.body); }
| REC '{' binds '}'
{ $3->recursive = true; $$ = $3; }
| '{' binds '}'
@ -530,23 +269,23 @@ string_parts
string_parts_interpolated
: string_parts_interpolated STR
{ $$ = $1; $1->emplace_back(makeCurPos(@2, data), new ExprString(std::string($2))); }
| string_parts_interpolated DOLLAR_CURLY expr '}' { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $3); }
| DOLLAR_CURLY expr '}' { $$ = new std::vector<std::pair<PosIdx, Expr *>>; $$->emplace_back(makeCurPos(@1, data), $2); }
{ $$ = $1; $1->emplace_back(state->at(@2), new ExprString(std::string($2))); }
| string_parts_interpolated DOLLAR_CURLY expr '}' { $$ = $1; $1->emplace_back(state->at(@2), $3); }
| DOLLAR_CURLY expr '}' { $$ = new std::vector<std::pair<PosIdx, Expr *>>; $$->emplace_back(state->at(@1), $2); }
| STR DOLLAR_CURLY expr '}' {
$$ = new std::vector<std::pair<PosIdx, Expr *>>;
$$->emplace_back(makeCurPos(@1, data), new ExprString(std::string($1)));
$$->emplace_back(makeCurPos(@2, data), $3);
$$->emplace_back(state->at(@1), new ExprString(std::string($1)));
$$->emplace_back(state->at(@2), $3);
}
;
path_start
: PATH {
Path path(absPath({$1.p, $1.l}, data->basePath.path.abs()));
Path path(absPath({$1.p, $1.l}, state->basePath.path.abs()));
/* add back in the trailing '/' to the first segment */
if ($1.p[$1.l-1] == '/' && $1.l > 1)
path += "/";
$$ = new ExprPath(ref<InputAccessor>(data->state.rootFS), std::move(path));
$$ = new ExprPath(ref<InputAccessor>(state->rootFS), std::move(path));
}
| HPATH {
if (evalSettings.pureEval) {
@ -556,24 +295,24 @@ path_start
);
}
Path path(getHome() + std::string($1.p + 1, $1.l - 1));
$$ = new ExprPath(ref<InputAccessor>(data->state.rootFS), std::move(path));
$$ = new ExprPath(ref<InputAccessor>(state->rootFS), std::move(path));
}
;
ind_string_parts
: ind_string_parts IND_STR { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $2); }
| ind_string_parts DOLLAR_CURLY expr '}' { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $3); }
: ind_string_parts IND_STR { $$ = $1; $1->emplace_back(state->at(@2), $2); }
| ind_string_parts DOLLAR_CURLY expr '}' { $$ = $1; $1->emplace_back(state->at(@2), $3); }
| { $$ = new std::vector<std::pair<PosIdx, std::variant<Expr *, StringToken>>>; }
;
binds
: binds attrpath '=' expr ';' { $$ = $1; addAttr($$, std::move(*$2), $4, makeCurPos(@2, data), data->state); delete $2; }
: binds attrpath '=' expr ';' { $$ = $1; state->addAttr($$, std::move(*$2), $4, state->at(@2)); delete $2; }
| binds INHERIT attrs ';'
{ $$ = $1;
for (auto & i : *$3) {
if ($$->attrs.find(i.symbol) != $$->attrs.end())
dupAttr(data->state, i.symbol, makeCurPos(@3, data), $$->attrs[i.symbol].pos);
auto pos = makeCurPos(@3, data);
state->dupAttr(i.symbol, state->at(@3), $$->attrs[i.symbol].pos);
auto pos = state->at(@3);
$$->attrs.emplace(i.symbol, ExprAttrs::AttrDef(new ExprVar(CUR_POS, i.symbol), pos, true));
}
delete $3;
@ -583,48 +322,48 @@ binds
/* !!! Should ensure sharing of the expression in $4. */
for (auto & i : *$6) {
if ($$->attrs.find(i.symbol) != $$->attrs.end())
dupAttr(data->state, i.symbol, makeCurPos(@6, data), $$->attrs[i.symbol].pos);
$$->attrs.emplace(i.symbol, ExprAttrs::AttrDef(new ExprSelect(CUR_POS, $4, i.symbol), makeCurPos(@6, data)));
state->dupAttr(i.symbol, state->at(@6), $$->attrs[i.symbol].pos);
$$->attrs.emplace(i.symbol, ExprAttrs::AttrDef(new ExprSelect(CUR_POS, $4, i.symbol), state->at(@6)));
}
delete $6;
}
| { $$ = new ExprAttrs(makeCurPos(@0, data)); }
| { $$ = new ExprAttrs(state->at(@0)); }
;
attrs
: attrs attr { $$ = $1; $1->push_back(AttrName(data->symbols.create($2))); }
: attrs attr { $$ = $1; $1->push_back(AttrName(state->symbols.create($2))); }
| attrs string_attr
{ $$ = $1;
ExprString * str = dynamic_cast<ExprString *>($2);
if (str) {
$$->push_back(AttrName(data->symbols.create(str->s)));
$$->push_back(AttrName(state->symbols.create(str->s)));
delete str;
} else
throw ParseError({
.msg = hintfmt("dynamic attributes not allowed in inherit"),
.errPos = data->state.positions[makeCurPos(@2, data)]
.errPos = state->positions[state->at(@2)]
});
}
| { $$ = new AttrPath; }
;
attrpath
: attrpath '.' attr { $$ = $1; $1->push_back(AttrName(data->symbols.create($3))); }
: attrpath '.' attr { $$ = $1; $1->push_back(AttrName(state->symbols.create($3))); }
| attrpath '.' string_attr
{ $$ = $1;
ExprString * str = dynamic_cast<ExprString *>($3);
if (str) {
$$->push_back(AttrName(data->symbols.create(str->s)));
$$->push_back(AttrName(state->symbols.create(str->s)));
delete str;
} else
$$->push_back(AttrName($3));
}
| attr { $$ = new std::vector<AttrName>; $$->push_back(AttrName(data->symbols.create($1))); }
| attr { $$ = new std::vector<AttrName>; $$->push_back(AttrName(state->symbols.create($1))); }
| string_attr
{ $$ = new std::vector<AttrName>;
ExprString *str = dynamic_cast<ExprString *>($1);
if (str) {
$$->push_back(AttrName(data->symbols.create(str->s)));
$$->push_back(AttrName(state->symbols.create(str->s)));
delete str;
} else
$$->push_back(AttrName($1));
@ -650,226 +389,52 @@ formals
: formal ',' formals
{ $$ = $3; $$->formals.emplace_back(*$1); delete $1; }
| formal
{ $$ = new ParserFormals; $$->formals.emplace_back(*$1); $$->ellipsis = false; delete $1; }
{ $$ = new Formals; $$->formals.emplace_back(*$1); $$->ellipsis = false; delete $1; }
|
{ $$ = new ParserFormals; $$->ellipsis = false; }
{ $$ = new Formals; $$->ellipsis = false; }
| ELLIPSIS
{ $$ = new ParserFormals; $$->ellipsis = true; }
{ $$ = new Formals; $$->ellipsis = true; }
;
formal
: ID { $$ = new Formal{CUR_POS, data->symbols.create($1), 0}; }
| ID '?' expr { $$ = new Formal{CUR_POS, data->symbols.create($1), $3}; }
: ID { $$ = new Formal{CUR_POS, state->symbols.create($1), 0}; }
| ID '?' expr { $$ = new Formal{CUR_POS, state->symbols.create($1), $3}; }
;
%%
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "eval.hh"
#include "filetransfer.hh"
#include "tarball.hh"
#include "store-api.hh"
#include "flake/flake.hh"
#include "fs-input-accessor.hh"
#include "memory-input-accessor.hh"
namespace nix {
unsigned long Expr::nrExprs = 0;
Expr * EvalState::parse(
Expr * parseExprFromBuf(
char * text,
size_t length,
Pos::Origin origin,
const SourcePath & basePath,
std::shared_ptr<StaticEnv> & staticEnv)
SymbolTable & symbols,
PosTable & positions,
const ref<InputAccessor> rootFS,
const Expr::AstSymbols & astSymbols)
{
yyscan_t scanner;
ParseData data {
.state = *this,
ParserState state {
.symbols = symbols,
.positions = positions,
.basePath = basePath,
.origin = {origin},
.rootFS = rootFS,
.s = astSymbols,
};
yylex_init(&scanner);
Finally _destroy([&] { yylex_destroy(scanner); });
yy_scan_buffer(text, length, scanner);
int res = yyparse(scanner, &data);
yylex_destroy(scanner);
yyparse(scanner, &state);
if (res) throw ParseError(data.error.value());
data.result->bindVars(*this, staticEnv);
return data.result;
}
SourcePath resolveExprPath(SourcePath path)
{
unsigned int followCount = 0, maxFollow = 1024;
/* If `path' is a symlink, follow it. This is so that relative
path references work. */
while (!path.path.isRoot()) {
// Basic cycle/depth limit to avoid infinite loops.
if (++followCount >= maxFollow)
throw Error("too many symbolic links encountered while traversing the path '%s'", path);
auto p = path.parent().resolveSymlinks() + path.baseName();
if (p.lstat().type != InputAccessor::tSymlink) break;
path = {path.accessor, CanonPath(p.readLink(), path.path.parent().value_or(CanonPath::root))};
}
/* If `path' refers to a directory, append `/default.nix'. */
if (path.resolveSymlinks().lstat().type == InputAccessor::tDirectory)
return path + "default.nix";
return path;
}
Expr * EvalState::parseExprFromFile(const SourcePath & path)
{
return parseExprFromFile(path, staticBaseEnv);
}
Expr * EvalState::parseExprFromFile(const SourcePath & path, std::shared_ptr<StaticEnv> & staticEnv)
{
auto buffer = path.resolveSymlinks().readFile();
// readFile hopefully have left some extra space for terminators
buffer.append("\0\0", 2);
return parse(buffer.data(), buffer.size(), Pos::Origin(path), path.parent(), staticEnv);
}
Expr * EvalState::parseExprFromString(std::string s_, const SourcePath & basePath, std::shared_ptr<StaticEnv> & staticEnv)
{
auto s = make_ref<std::string>(std::move(s_));
s->append("\0\0", 2);
return parse(s->data(), s->size(), Pos::String{.source = s}, basePath, staticEnv);
}
Expr * EvalState::parseExprFromString(std::string s, const SourcePath & basePath)
{
return parseExprFromString(std::move(s), basePath, staticBaseEnv);
}
Expr * EvalState::parseStdin()
{
//Activity act(*logger, lvlTalkative, "parsing standard input");
auto buffer = drainFD(0);
// drainFD should have left some extra space for terminators
buffer.append("\0\0", 2);
auto s = make_ref<std::string>(std::move(buffer));
return parse(s->data(), s->size(), Pos::Stdin{.source = s}, rootPath(CanonPath::fromCwd()), staticBaseEnv);
}
SourcePath EvalState::findFile(const std::string_view path)
{
return findFile(searchPath, path);
}
SourcePath EvalState::findFile(const SearchPath & searchPath, const std::string_view path, const PosIdx pos)
{
for (auto & i : searchPath.elements) {
auto suffixOpt = i.prefix.suffixIfPotentialMatch(path);
if (!suffixOpt) continue;
auto suffix = *suffixOpt;
auto rOpt = resolveSearchPathPath(i.path);
if (!rOpt) continue;
auto r = *rOpt;
Path res = suffix == "" ? r : concatStrings(r, "/", suffix);
if (pathExists(res)) return rootPath(CanonPath(canonPath(res)));
}
if (hasPrefix(path, "nix/"))
return {corepkgsFS, CanonPath(path.substr(3))};
debugThrow(ThrownError({
.msg = hintfmt(evalSettings.pureEval
? "cannot look up '<%s>' in pure evaluation mode (use '--impure' to override)"
: "file '%s' was not found in the Nix search path (add it using $NIX_PATH or -I)",
path),
.errPos = positions[pos]
}), 0, 0);
}
std::optional<std::string> EvalState::resolveSearchPathPath(const SearchPath::Path & value0, bool initAccessControl)
{
auto & value = value0.s;
auto i = searchPathResolved.find(value);
if (i != searchPathResolved.end()) return i->second;
std::optional<std::string> res;
if (EvalSettings::isPseudoUrl(value)) {
try {
auto storePath = fetchers::downloadTarball(
store, EvalSettings::resolvePseudoUrl(value), "source", false).storePath;
res = { store->toRealPath(storePath) };
} catch (FileTransferError & e) {
logWarning({
.msg = hintfmt("Nix search path entry '%1%' cannot be downloaded, ignoring", value)
});
}
}
else if (hasPrefix(value, "flake:")) {
experimentalFeatureSettings.require(Xp::Flakes);
auto flakeRef = parseFlakeRef(value.substr(6), {}, true, false);
debug("fetching flake search path element '%s''", value);
auto storePath = flakeRef.resolve(store).fetchTree(store).first;
res = { store->toRealPath(storePath) };
}
else {
auto path = absPath(value);
/* Allow access to paths in the search path. */
if (initAccessControl) {
allowPath(path);
if (store->isInStore(path)) {
try {
StorePathSet closure;
store->computeFSClosure(store->toStorePath(path).first, closure);
for (auto & p : closure)
allowPath(p);
} catch (InvalidPath &) { }
}
}
if (pathExists(path))
res = { path };
else {
logWarning({
.msg = hintfmt("Nix search path entry '%1%' does not exist, ignoring", value)
});
res = std::nullopt;
}
}
if (res)
debug("resolved search path element '%s' to '%s'", value, *res);
else
debug("failed to resolve search path element '%s'", value);
searchPathResolved.emplace(value, res);
return res;
return state.result;
}