lix/src/libexpr/eval-inline.hh
John Ericson 0746951be1
Finish converting existing comments for internal API docs (#8146)
* Finish converting existing comments for internal API docs

99% of this was just reformatting existing comments. Only two exceptions:

- Expanded upon `BuildResult::status` compat note

- Split up file-level `symbol-table.hh` doc comments to get
  per-definition docs

Also fixed a few whitespace goofs, turning leading tabs to spaces and
removing trailing spaces.

Picking up from #8133

* Fix two things from comments

* Use triple-backtick not indent for `dumpPath`

* Convert GNU-style `\`..'` quotes to markdown style in API docs

This will render correctly.
2023-04-07 13:55:28 +00:00

143 lines
3.5 KiB
C++

#pragma once
///@file
#include "eval.hh"
namespace nix {
/**
* Note: Various places expect the allocated memory to be zeroed.
*/
[[gnu::always_inline]]
inline void * allocBytes(size_t n)
{
void * p;
#if HAVE_BOEHMGC
p = GC_MALLOC(n);
#else
p = calloc(n, 1);
#endif
if (!p) throw std::bad_alloc();
return p;
}
[[gnu::always_inline]]
Value * EvalState::allocValue()
{
#if HAVE_BOEHMGC
/* We use the boehm batch allocator to speed up allocations of Values (of which there are many).
GC_malloc_many returns a linked list of objects of the given size, where the first word
of each object is also the pointer to the next object in the list. This also means that we
have to explicitly clear the first word of every object we take. */
if (!*valueAllocCache) {
*valueAllocCache = GC_malloc_many(sizeof(Value));
if (!*valueAllocCache) throw std::bad_alloc();
}
/* GC_NEXT is a convenience macro for accessing the first word of an object.
Take the first list item, advance the list to the next item, and clear the next pointer. */
void * p = *valueAllocCache;
*valueAllocCache = GC_NEXT(p);
GC_NEXT(p) = nullptr;
#else
void * p = allocBytes(sizeof(Value));
#endif
nrValues++;
return (Value *) p;
}
[[gnu::always_inline]]
Env & EvalState::allocEnv(size_t size)
{
nrEnvs++;
nrValuesInEnvs += size;
Env * env;
#if HAVE_BOEHMGC
if (size == 1) {
/* see allocValue for explanations. */
if (!*env1AllocCache) {
*env1AllocCache = GC_malloc_many(sizeof(Env) + sizeof(Value *));
if (!*env1AllocCache) throw std::bad_alloc();
}
void * p = *env1AllocCache;
*env1AllocCache = GC_NEXT(p);
GC_NEXT(p) = nullptr;
env = (Env *) p;
} else
#endif
env = (Env *) allocBytes(sizeof(Env) + size * sizeof(Value *));
env->type = Env::Plain;
/* We assume that env->values has been cleared by the allocator; maybeThunk() and lookupVar fromWith expect this. */
return *env;
}
[[gnu::always_inline]]
void EvalState::forceValue(Value & v, const PosIdx pos)
{
forceValue(v, [&]() { return pos; });
}
template<typename Callable>
void EvalState::forceValue(Value & v, Callable getPos)
{
if (v.isThunk()) {
Env * env = v.thunk.env;
Expr * expr = v.thunk.expr;
try {
v.mkBlackhole();
//checkInterrupt();
expr->eval(*this, *env, v);
} catch (...) {
v.mkThunk(env, expr);
throw;
}
}
else if (v.isApp())
callFunction(*v.app.left, *v.app.right, v, noPos);
else if (v.isBlackhole())
error("infinite recursion encountered").atPos(getPos()).template debugThrow<EvalError>();
}
[[gnu::always_inline]]
inline void EvalState::forceAttrs(Value & v, const PosIdx pos, std::string_view errorCtx)
{
forceAttrs(v, [&]() { return pos; }, errorCtx);
}
template <typename Callable>
[[gnu::always_inline]]
inline void EvalState::forceAttrs(Value & v, Callable getPos, std::string_view errorCtx)
{
forceValue(v, noPos);
if (v.type() != nAttrs) {
PosIdx pos = getPos();
error("value is %1% while a set was expected", showType(v)).withTrace(pos, errorCtx).debugThrow<TypeError>();
}
}
[[gnu::always_inline]]
inline void EvalState::forceList(Value & v, const PosIdx pos, std::string_view errorCtx)
{
forceValue(v, noPos);
if (!v.isList()) {
error("value is %1% while a list was expected", showType(v)).withTrace(pos, errorCtx).debugThrow<TypeError>();
}
}
}