-#include "paxos.h"
-#include <fstream>
-#include <iostream>
-#include "threaded_log.h"
+#include "include/log.h"
+#include "include/paxos.h"
-// Paxos must maintain some durable state (i.e., that survives power
-// failures) to run Paxos correct. This module implements a log with
-// all durable state to run Paxos. Since the values chosen correspond
-// to views, the log contains all views since the beginning of time.
+// Maintains durable state (i.e. surviving power failures) needed for correct
+// operation of Paxos as a log.
-log::log(acceptor *_acc, std::string _me) : pxs (_acc) {
- name = "paxos-" + _me + ".log";
- logread();
-}
+log::log(string _me) : name("paxos-" + _me + ".log") {}
-void log::logread(void) {
- std::ifstream from;
- std::string type;
- unsigned instance;
+void log::replay() {
+ auto from = unmarshall(read());
+ string type;
- from.open(name.c_str());
- LOG("logread");
+ DEBUG_LOG << "Replaying paxos log from disk";
while (from >> type) {
- if (type == "done") {
- std::string v;
- from >> instance;
- from.get();
- getline(from, v);
- pxs->values[instance] = v;
- pxs->instance_h = instance;
- LOG("logread: instance: " << instance << " w. v = " <<
- pxs->values[instance]);
- pxs->v_a.clear();
- pxs->n_h.n = 0;
- pxs->n_a.n = 0;
- } else if (type == "propseen") {
- from >> pxs->n_h.n;
- from >> pxs->n_h.m;
- LOG("logread: high update: " << pxs->n_h.n << "(" << pxs->n_h.m << ")");
- } else if (type == "accepted") {
- std::string v;
- from >> pxs->n_a.n;
- from >> pxs->n_a.m;
- from.get();
- getline(from, v);
- pxs->v_a = v;
- LOG("logread: prop update " << pxs->n_a.n << "(" << pxs->n_a.m << ") with v = " << pxs->v_a);
+ if (handlers.count(type)) {
+ handlers[type](from);
} else {
- LOG("logread: unknown log record");
+ DEBUG_LOG << "unknown log record";
VERIFY(0);
}
- }
- from.close();
-}
-
-std::string log::dump() {
- std::ifstream from;
- std::string res;
- std::string v;
- from.open(name.c_str());
- while (getline(from, v))
- res += v + "\n";
- from.close();
- return res;
-}
-
-void log::restore(std::string s) {
- std::ofstream f;
- LOG("restore: " << s);
- f.open(name.c_str(), std::ios::trunc);
- f << s;
- f.close();
-}
-
-// XXX should be an atomic operation
-void log::loginstance(unsigned instance, std::string v) {
- std::ofstream f(name, std::ios::app);
- f << "done " << instance << " " << v << "\n";
- f.close();
+ }
}
-// an acceptor should call logprop(n_h) when it
-// receives a prepare to which it responds prepare_ok().
-void log::logprop(prop_t n_h) {
- std::ofstream f;
- f.open(name.c_str(), std::ios::app);
- f << "propseen";
- f << " ";
- f << n_h.n;
- f << " ";
- f << n_h.m;
- f << "\n";
- f.close();
+string log::read() {
+ return (std::stringstream() << std::ifstream(name).rdbuf()).str();
}
-// an acceptor should call logaccept(n_a, v_a) when it
-// receives an accept RPC to which it replies accept_ok().
-void log::logaccept(prop_t n, std::string v) {
- std::ofstream f(name, std::ios::app);
- f << "accepted " << n.n << " " << n.m << " " << v << "\n";
- f.close();
+void log::write(string s) {
+ DEBUG_LOG << s;
+ std::ofstream(name, std::ios::trunc) << s;
}