diff options
Diffstat (limited to 'libbuild2/depdb.hxx')
| -rw-r--r-- | libbuild2/depdb.hxx | 41 |
1 files changed, 37 insertions, 4 deletions
diff --git a/libbuild2/depdb.hxx b/libbuild2/depdb.hxx index 5b5052d..55413bf 100644 --- a/libbuild2/depdb.hxx +++ b/libbuild2/depdb.hxx @@ -62,12 +62,14 @@ namespace build2 // struct LIBBUILD2_SYMEXPORT depdb_base { - explicit - depdb_base (const path&, timestamp); + // Implementation details. + // + enum class state {read, read_eof, write}; + depdb_base (const path&, state, optional<uint64_t> pos = nullopt); ~depdb_base (); - enum class state {read, read_eof, write} state_; + state state_; union { @@ -113,6 +115,27 @@ namespace build2 explicit depdb (path_type); + struct reopen_state + { + path_type path; + uint64_t pos; + timestamp mtime; + }; + + // Reopen the database for writing. The reopen state must have been + // obtained by calling close_to_reopen() below. Besides opening the file + // and adjusting its write position, this constructor also sets touch to + // the timestamp returned by close_to_reopen() to help maintain the + // "database mtime is before target mtime" invariant. + // + // This functionality is primarily useful to handle dynamic dependency + // information that is produced as a byproduct of compilation. In this + // case the "static" part of the database is written in match and the + // "dynamic" part -- in execute. + // + explicit + depdb (reopen_state); + // Close the database. If this function is not called, then the database // may be left in the old/currupt state. Note that in the read mode this // function will "chop off" lines that haven't been read. @@ -125,6 +148,16 @@ namespace build2 void close (bool mtime_check = true); + // Temporarily close the database to be reopened for writing later. + // Besides the file path and write position also return the database file + // modification time after closing. + // + // Note that after this call the resulting database file is valid and if + // it's not reopened later, the result is equivalent to calling close(). + // + reopen_state + close_to_reopen (); + // Flush any unwritten data to disk. This is primarily useful when reusing // a (partially written) database as an input to external programs (e.g., // as a module map). @@ -158,7 +191,7 @@ namespace build2 // the next line in the database (which you are free to move from). If you // then call write(), this line will be overwritten. // - // If the result is NULL, then it means no next line is unavailable. This + // If the result is NULL, then it means no next line is available. This // can be due to several reasons: // // - eof reached (you can detect this by calling more() before read()) |