#pragma once

#include "types.hh"


namespace nix {


/* Open (possibly create) a lock file and return the file descriptor.
   -1 is returned if create is false and the lock could not be opened
   because it doesn't exist.  Any other error throws an exception. */
int openLockFile(const Path & path, bool create);

/* Delete an open lock file. */
void deleteLockFile(const Path & path, int fd);

enum LockType { ltRead, ltWrite, ltNone };

bool lockFile(int fd, LockType lockType, bool wait);


class PathLocks 
{
private:
    typedef std::pair<int, Path> FDPair;
    list<FDPair> fds;
    bool deletePaths;

public:
    PathLocks();
    PathLocks(const PathSet & paths,
        const string & waitMsg = "");
    bool lockPaths(const PathSet & _paths,
        const string & waitMsg = "",
        bool wait = true);
    ~PathLocks();
    void unlock();
    void setDeletion(bool deletePaths);
};


bool pathIsLockedByMe(const Path & path);


}
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<div class='path'>path: <a href='/guix/log/?id=079c2aaf491568c70c230469ee45d2ebecd7899d'>root</a>/<a href='/guix/log/d3.v3.js?id=079c2aaf491568c70c230469ee45d2ebecd7899d'>d3.v3.js</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/d3.v3.js?id=079c2aaf491568c70c230469ee45d2ebecd7899d&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2016-12-14 21:58:32 +0100'>2016-12-14</span></td><td><a href='/guix/commit/d3.v3.js?id=4d93f312f084c34a70cf7da3abe5f92a74d76861'>graph: Add d3js backend.</a><span class='msg-avail'>...<span class='msg-tooltip'>* d3.v3.js, graph.js: New files.
* Makefile.am (EXTRA_DIST): List them.
* guix/graph.scm (%d3js-backend): New variable.
(emit-d3js-prologue, emit-d3js-epilogue, emit-d3js-node,
emit-d3js-edge): New procedures.
(%graph-backends): Add %d3js-backend.
</span></span></td><td>Ricardo Wurmus</td></tr>