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authorEvan Martin <martine@danga.com>2013-01-08 16:20:56 (GMT)
committerEvan Martin <martine@danga.com>2013-04-08 22:01:44 (GMT)
commite280115c03a296078b26da4b10a643cb1a6bda8a (patch)
tree36bc376ae939ee4268dfceb71c195530e5a9d51a /src/deps_log.h
parente801e67a4cfae117098f252d365d67704eba4bfd (diff)
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clarify depslog overview
Diffstat (limited to 'src/deps_log.h')
-rw-r--r--src/deps_log.h9
1 files changed, 5 insertions, 4 deletions
diff --git a/src/deps_log.h b/src/deps_log.h
index 5ddc7bd..56f9590 100644
--- a/src/deps_log.h
+++ b/src/deps_log.h
@@ -27,10 +27,10 @@ struct Node;
struct State;
/// As build commands run they can output extra dependency information
-/// (e.g. header dependencies for C source) via a pipe. DepsLog collects
-/// that information at build time and reloads it at startup.
+/// (e.g. header dependencies for C source) dynamically. DepsLog collects
+/// that information at build time and uses it for subsequent builds.
///
-/// The on-disk format is based on two primary constraints:
+/// The on-disk format is based on two primary design constraints:
/// - it must be written to as a stream (during the build, which may be
/// interrupted);
/// - it can be read all at once on startup. (Alternative designs, where
@@ -43,7 +43,8 @@ struct State;
/// There's about 10k files worth of dependencies that reference about
/// 40k total paths totalling 2mb of unique strings.
///
-/// Based on these above, the file is structured as a sequence of records.
+/// Based on these stats, here's the current design.
+/// The file is structured as version header followed by a sequence of records.
/// Each record is either a path string or a dependency list.
/// Numbering the path strings in file order gives them dense integer ids.
/// A dependency list maps an output id to a list of input ids.