lix/src/libexpr/symbol-table.hh
Tuomas Tynkkynen 2cd468874f Include config.h implicitly with '-include config.h' in CFLAGS
Because config.h can #define things like _FILE_OFFSET_BITS=64 and not
every compilation unit includes config.h, we currently compile half of
Nix with _FILE_OFFSET_BITS=64 and other half with _FILE_OFFSET_BITS
unset. This causes major havoc with the Settings class on e.g. 32-bit ARM,
where different compilation units disagree with the struct layout.

E.g.:

diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
@@ -166,6 +166,8 @@ void Settings::update()
     _get(useSubstitutes, "build-use-substitutes");
+    fprintf(stderr, "at Settings::update(): &useSubstitutes = %p\n", &nix::settings.useSubstitutes);
     _get(buildUsersGroup, "build-users-group");
diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -138,6 +138,8 @@ void RemoteStore::initConnection(Connection & conn)
 void RemoteStore::setOptions(Connection & conn)
 {
+    fprintf(stderr, "at RemoteStore::setOptions(): &useSubstitutes = %p\n", &nix::settings.useSubstitutes);
     conn.to << wopSetOptions

Gave me:

at Settings::update(): &useSubstitutes = 0xb6e5c5cb
at RemoteStore::setOptions(): &useSubstitutes = 0xb6e5c5c7

That was not a fun one to debug!
2017-02-08 21:51:02 +02:00

81 lines
1.5 KiB
C++

#pragma once
#include <map>
#include <unordered_set>
#include "types.hh"
namespace nix {
/* Symbol table used by the parser and evaluator to represent and look
up identifiers and attributes efficiently. SymbolTable::create()
converts a string into a symbol. Symbols have the property that
they can be compared efficiently (using a pointer equality test),
because the symbol table stores only one copy of each string. */
class Symbol
{
private:
const string * s; // pointer into SymbolTable
Symbol(const string * s) : s(s) { };
friend class SymbolTable;
public:
Symbol() : s(0) { };
bool operator == (const Symbol & s2) const
{
return s == s2.s;
}
bool operator != (const Symbol & s2) const
{
return s != s2.s;
}
bool operator < (const Symbol & s2) const
{
return s < s2.s;
}
operator const string & () const
{
return *s;
}
bool set() const
{
return s;
}
bool empty() const
{
return s->empty();
}
friend std::ostream & operator << (std::ostream & str, const Symbol & sym);
};
class SymbolTable
{
private:
typedef std::unordered_set<string> Symbols;
Symbols symbols;
public:
Symbol create(const string & s)
{
std::pair<Symbols::iterator, bool> res = symbols.insert(s);
return Symbol(&*res.first);
}
unsigned int size() const
{
return symbols.size();
}
size_t totalSize() const;
};
}