# HG changeset patch
# User Artem Tikhomirov <tikhomirov.artem@gmail.com>
# Date 1307069409 -7200
# Node ID 1d389c0cb0a5ef03d4249aeffb2fdebba9dcb1e7
# Parent  b7347daa50e33f93c836e7d0eafe851015c5f4d9
Optimize file history walk not to iterat over whole changelog for sparse and distant revisions

diff -r b7347daa50e3 -r 1d389c0cb0a5 cmdline/org/tmatesoft/hg/console/Main.java
--- a/cmdline/org/tmatesoft/hg/console/Main.java	Thu Jun 02 05:13:39 2011 +0200
+++ b/cmdline/org/tmatesoft/hg/console/Main.java	Fri Jun 03 04:50:09 2011 +0200
@@ -23,6 +23,7 @@
 import java.util.List;
 import java.util.Map;
 
+import org.tmatesoft.hg.core.HgLogCommand;
 import org.tmatesoft.hg.core.HgLogCommand.FileRevision;
 import org.tmatesoft.hg.core.HgCatCommand;
 import org.tmatesoft.hg.core.HgFileRevision;
@@ -32,6 +33,7 @@
 import org.tmatesoft.hg.internal.DigestHelper;
 import org.tmatesoft.hg.internal.PathGlobMatcher;
 import org.tmatesoft.hg.repo.HgBranches;
+import org.tmatesoft.hg.repo.HgChangelog;
 import org.tmatesoft.hg.repo.HgDataFile;
 import org.tmatesoft.hg.repo.HgInternals;
 import org.tmatesoft.hg.repo.HgManifest;
@@ -40,6 +42,7 @@
 import org.tmatesoft.hg.repo.HgStatusCollector;
 import org.tmatesoft.hg.repo.HgStatusInspector;
 import org.tmatesoft.hg.repo.HgWorkingCopyStatusCollector;
+import org.tmatesoft.hg.repo.HgChangelog.RawChangeset;
 import org.tmatesoft.hg.util.Path;
 
 /**
@@ -65,7 +68,8 @@
 
 	public static void main(String[] args) throws Exception {
 		Main m = new Main(args);
-		m.testCatAtCsetRevision();
+		m.testEffectiveFileLog();
+//		m.testCatAtCsetRevision();
 //		m.testMergeState();
 //		m.testFileStatus();
 //		m.dumpBranches();
@@ -79,6 +83,20 @@
 //		m.bunchOfTests();
 	}
 	
+	private void testEffectiveFileLog() {
+		for (String fname : cmdLineOpts.getList("")) {
+			System.out.println(fname);
+			HgDataFile fn = hgRepo.getFileNode(fname);
+			if (fn.exists()) {
+				fn.history(new HgChangelog.Inspector() {
+					public void next(int revisionNumber, Nodeid nodeid, RawChangeset cset) {
+						System.out.printf("%d:%s\n", revisionNumber, nodeid);
+					}
+				});
+			}
+		}
+	}
+	
 	// TODO as test in TestCat
 	private void testCatAtCsetRevision() throws Exception {
 		HgCatCommand cmd = new HgCatCommand(hgRepo);
@@ -112,7 +130,7 @@
 //		final Path path = Path.create("src/org/tmatesoft/hg/internal/Experimental.java");
 //		final Path path = Path.create("missing-dir/");
 //		HgWorkingCopyStatusCollector wcsc = HgWorkingCopyStatusCollector.create(hgRepo, path);
-		HgWorkingCopyStatusCollector wcsc = HgWorkingCopyStatusCollector.create(hgRepo, new PathGlobMatcher("missing-dir/**/*"));
+		HgWorkingCopyStatusCollector wcsc = HgWorkingCopyStatusCollector.create(hgRepo, new PathGlobMatcher("mi**"));
 		wcsc.walk(TIP, new StatusDump());
 	}
 	
diff -r b7347daa50e3 -r 1d389c0cb0a5 src/org/tmatesoft/hg/repo/HgDataFile.java
--- a/src/org/tmatesoft/hg/repo/HgDataFile.java	Thu Jun 02 05:13:39 2011 +0200
+++ b/src/org/tmatesoft/hg/repo/HgDataFile.java	Fri Jun 03 04:50:09 2011 +0200
@@ -176,7 +176,37 @@
 			}
 		};
 		content.iterate(start, end, false, insp);
-		getRepo().getChangelog().range(inspector, commitRevisions);
+		final HgChangelog changelog = getRepo().getChangelog();
+//		changelog.range(inspector, commitRevisions); not effective when changes are sparse and far from each other
+		//
+		final int HistoricallyCloseCommits = 50; // XXX perhaps, shall increase/decrease based on changelog.revisionCount() 
+		// (huge changelog => memory mapped files, each file re-read is more expensive than iterating over records in one read?
+		//
+		// try short sequences on neighboring revisions.
+		for (int i = 0; i < commitRevisions.length; ) {
+			int x = i;
+			i++;
+			boolean sequential = true;
+			while (i < commitRevisions.length) {
+				if (commitRevisions[i] == commitRevisions[i-1] + 1) {
+					i++;
+				} else if (commitRevisions[i] - commitRevisions[i-1] < HistoricallyCloseCommits) {
+					// close enough, but not sequential
+					sequential = false;
+					i++;
+				} else {
+					break;
+				}
+			}
+			if (sequential) {
+				// commitRevisions[x..i-1] are sequential
+				changelog.range(commitRevisions[x], commitRevisions[i-1], inspector);
+			} else {
+				int[] revs = new int[i-x];
+				System.arraycopy(commitRevisions, x, revs, 0, i-x);
+				changelog.range(inspector, revs);
+			}
+		}
 	}
 	
 	// for a given local revision of the file, find out local revision in the changelog