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DepsLog Struct Reference

As build commands run they can output extra dependency information (e.g. More...

#include <deps_log.h>

Classes

struct  Deps
 

Public Member Functions

void Close ()
 
const vector< Deps * > & deps () const
 
 DepsLog ()
 
DepsGetDeps (Node *node)
 
bool IsDepsEntryLiveFor (Node *node)
 Returns if the deps entry for a node is still reachable from the manifest. More...
 
bool Load (const string &path, State *state, string *err)
 
const vector< Node * > & nodes () const
 Used for tests. More...
 
bool OpenForWrite (const string &path, string *err)
 
bool Recompact (const string &path, string *err)
 Rewrite the known log entries, throwing away old data. More...
 
bool RecordDeps (Node *node, TimeStamp mtime, const vector< Node * > &nodes)
 
bool RecordDeps (Node *node, TimeStamp mtime, int node_count, Node **nodes)
 
 ~DepsLog ()
 

Private Member Functions

bool RecordId (Node *node)
 
bool UpdateDeps (int out_id, Deps *deps)
 

Private Attributes

vector< Deps * > deps_
 Maps id -> deps of that id. More...
 
FILE * file_
 
bool needs_recompaction_
 
vector< Node * > nodes_
 Maps id -> Node. More...
 

Friends

struct DepsLogTest
 

Detailed Description

As build commands run they can output extra dependency information (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 design constraints:

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.

Concretely, a record is: four bytes record length, high bit indicates record type (but max record sizes are capped at 512kB) path records contain the string name of the path, followed by up to 3 padding bytes to align on 4 byte boundaries, followed by the one's complement of the expected index of the record (to detect concurrent writes of multiple ninja processes to the log). dependency records are an array of 4-byte integers output path id, output path mtime, input path id, input path id... If two records reference the same output the latter one in the file wins, allowing updates to just be appended to the file. A separate repacking step can run occasionally to remove dead records.

Definition at line 66 of file deps_log.h.

Constructor & Destructor Documentation

DepsLog::DepsLog ( )
inline

Definition at line 67 of file deps_log.h.

DepsLog::~DepsLog ( )

Definition at line 39 of file deps_log.cc.

References Close().

Member Function Documentation

void DepsLog::Close ( )

Definition at line 158 of file deps_log.cc.

References file_.

Referenced by Recompact(), TEST_F(), and ~DepsLog().

const vector<Deps*>& DepsLog::deps ( ) const
inline

Definition at line 101 of file deps_log.h.

Referenced by Load(), Recompact(), RecordDeps(), and UpdateDeps().

DepsLog::Deps * DepsLog::GetDeps ( Node node)

Definition at line 295 of file deps_log.cc.

References deps_, and Node::id().

Referenced by RecordDeps().

bool DepsLog::IsDepsEntryLiveFor ( Node node)

Returns if the deps entry for a node is still reachable from the manifest.

The deps log can contain deps entries for files that were built in the past but are no longer part of the manifest. This function returns if this is the case for a given node. This function is slow, don't call it from code that runs on every build.

Definition at line 357 of file deps_log.cc.

References Edge::GetBinding(), and Node::in_edge().

Referenced by Recompact().

bool DepsLog::Load ( const string &  path,
State state,
string *  err 
)
const vector<Node*>& DepsLog::nodes ( ) const
inline

Used for tests.

Definition at line 100 of file deps_log.h.

bool DepsLog::OpenForWrite ( const string &  path,
string *  err 
)
bool DepsLog::Recompact ( const string &  path,
string *  err 
)

Rewrite the known log entries, throwing away old data.

Definition at line 303 of file deps_log.cc.

References Close(), deps(), deps_, IsDepsEntryLiveFor(), METRIC_RECORD, DepsLog::Deps::mtime, DepsLog::Deps::node_count, DepsLog::Deps::nodes, and nodes_.

Referenced by OpenForWrite().

bool DepsLog::RecordDeps ( Node node,
TimeStamp  mtime,
const vector< Node * > &  nodes 
)

Definition at line 80 of file deps_log.cc.

Referenced by Builder::FinishCommand().

bool DepsLog::RecordDeps ( Node node,
TimeStamp  mtime,
int  node_count,
Node **  nodes 
)
bool DepsLog::RecordId ( Node node)
private

Definition at line 378 of file deps_log.cc.

References file_, kMaxRecordSize, nodes_, Node::path(), and Node::set_id().

Referenced by RecordDeps().

bool DepsLog::UpdateDeps ( int  out_id,
Deps deps 
)
private

Definition at line 367 of file deps_log.cc.

References deps(), and deps_.

Referenced by Load(), and RecordDeps().

Friends And Related Function Documentation

friend struct DepsLogTest
friend

Definition at line 118 of file deps_log.h.

Member Data Documentation

vector<Deps*> DepsLog::deps_
private

Maps id -> deps of that id.

Definition at line 116 of file deps_log.h.

Referenced by GetDeps(), Recompact(), and UpdateDeps().

FILE* DepsLog::file_
private

Definition at line 111 of file deps_log.h.

Referenced by Close(), OpenForWrite(), RecordDeps(), and RecordId().

bool DepsLog::needs_recompaction_
private

Definition at line 110 of file deps_log.h.

Referenced by Load(), and OpenForWrite().

vector<Node*> DepsLog::nodes_
private

Maps id -> Node.

Definition at line 114 of file deps_log.h.

Referenced by Load(), Recompact(), and RecordId().


The documentation for this struct was generated from the following files: