From 552682dc6aa8f3a77fac9a2d25a20914fcc65ba0 Mon Sep 17 00:00:00 2001 From: "Shawn O. Pearce" Date: Tue, 27 Mar 2012 11:49:13 -0400 Subject: [PATCH] Sort Config entries and use O(log N) lookup Decrease running time for getStringList (and all other get methods) by looking for configuration entries using binary search rather than linear search through the configuration file. Configuration lines are sorted by section, subsection, name in a sorted list whenever the snapshot is rebuilt. Binary search is used to locate an index in the middle of the values, then walk backwards to find the first value in the range. Given a configuration of file of 5000 distinct section/subsection/name triplets (e.g. a Gerrit Code Review project.config configuration file with 5000 unique access control rules), this new code is faster to lookup each rule individually using getStringList(): old setStringList() 194 usec avg getStringList() 196 usec avg new setStringList() 188 usec avg getStringList() 24 usec avg Change-Id: Ic8907231868c18eb946b72f341a6b58666b70324 --- .../src/org/eclipse/jgit/lib/Config.java | 56 ++++----- .../org/eclipse/jgit/lib/ConfigSnapshot.java | 106 +++++++++++++++++- .../org/eclipse/jgit/util/StringUtils.java | 44 ++++++++ 3 files changed, 167 insertions(+), 39 deletions(-) diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Config.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Config.java index cf166d5b9c..58a03bf8bf 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Config.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Config.java @@ -456,22 +456,22 @@ public class Config { */ public String[] getStringList(final String section, String subsection, final String name) { - final String[] baseList; + String[] base; if (baseConfig != null) - baseList = baseConfig.getStringList(section, subsection, name); + base = baseConfig.getStringList(section, subsection, name); else - baseList = EMPTY_STRING_ARRAY; - - final List lst = getRawStringList(section, subsection, name); - if (lst != null) { - final String[] res = new String[baseList.length + lst.size()]; - int idx = baseList.length; - System.arraycopy(baseList, 0, res, 0, idx); - for (final String val : lst) - res[idx++] = val; - return res; - } - return baseList; + base = EMPTY_STRING_ARRAY; + + String[] self = getRawStringList(section, subsection, name); + if (self == null) + return base; + if (base.length == 0) + return self; + String[] res = new String[base.length + self.length]; + int n = base.length; + System.arraycopy(base, 0, res, 0, n); + System.arraycopy(self, 0, res, n, self.length); + return res; } /** @@ -588,36 +588,18 @@ public class Config { private String getRawString(final String section, final String subsection, final String name) { - final List lst = getRawStringList(section, subsection, name); + String[] lst = getRawStringList(section, subsection, name); if (lst != null) - return lst.get(0); + return lst[0]; else if (baseConfig != null) return baseConfig.getRawString(section, subsection, name); else return null; } - private List getRawStringList(final String section, - final String subsection, final String name) { - List r = null; - for (final ConfigLine e : state.get().entryList) { - if (e.match(section, subsection, name)) - r = add(r, e.value); - } - return r; - } - - private static List add(final List curr, final String value) { - if (curr == null) - return Collections.singletonList(value); - if (curr.size() == 1) { - final List r = new ArrayList(2); - r.add(curr.get(0)); - r.add(value); - return r; - } - curr.add(value); - return curr; + private String[] getRawStringList(String section, String subsection, + String name) { + return state.get().get(section, subsection, name); } private ConfigSnapshot getState() { diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigSnapshot.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigSnapshot.java index 61e4e0c93e..5527267b86 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigSnapshot.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigSnapshot.java @@ -2,8 +2,7 @@ * Copyright (C) 2010, Mathias Kinzler * Copyright (C) 2009, Constantine Plotnikov * Copyright (C) 2007, Dave Watson - * Copyright (C) 2008-2010, Google Inc. - * Copyright (C) 2009, Google, Inc. + * Copyright (C) 2008-2012, Google Inc. * Copyright (C) 2009, JetBrains s.r.o. * Copyright (C) 2007-2008, Robin Rosenberg * Copyright (C) 2006-2008, Shawn O. Pearce @@ -51,6 +50,12 @@ package org.eclipse.jgit.lib; +import static org.eclipse.jgit.util.StringUtils.compareIgnoreCase; +import static org.eclipse.jgit.util.StringUtils.compareWithCase; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.Comparator; import java.util.List; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; @@ -59,10 +64,107 @@ class ConfigSnapshot { final List entryList; final Map cache; final ConfigSnapshot baseState; + volatile List sorted; ConfigSnapshot(List entries, ConfigSnapshot base) { entryList = entries; cache = new ConcurrentHashMap(16, 0.75f, 1); baseState = base; } + + String[] get(String section, String subsection, String name) { + List s = sorted(); + int idx = find(s, section, subsection, name); + if (idx < 0) + return null; + int end = end(s, idx, section, subsection, name); + String[] r = new String[end - idx]; + for (int i = 0; idx < end;) + r[i++] = s.get(idx++).value; + return r; + } + + private int find(List s, String s1, String s2, String name) { + int low = 0; + int high = s.size(); + while (low < high) { + int mid = (low + high) >>> 1; + ConfigLine e = s.get(mid); + int cmp = compare2( + s1, s2, name, + e.section, e.subsection, e.name); + if (cmp < 0) + high = mid; + else if (cmp == 0) + return first(s, mid, s1, s2, name); + else + low = mid + 1; + } + return -(low + 1); + } + + private int first(List s, int i, String s1, String s2, String n) { + while (0 < i) { + if (s.get(i - 1).match(s1, s2, n)) + i--; + else + return i; + } + return i; + } + + private int end(List s, int i, String s1, String s2, String n) { + while (i < s.size()) { + if (s.get(i).match(s1, s2, n)) + i++; + else + return i; + } + return i; + } + + private List sorted() { + List r = sorted; + if (r == null) + sorted = r = sort(entryList); + return r; + } + + private static List sort(List in) { + List sorted = new ArrayList(in.size()); + for (ConfigLine line : in) { + if (line.section != null && line.name != null) + sorted.add(line); + } + Collections.sort(sorted, new LineComparator()); + return sorted; + } + + private static int compare2( + String aSection, String aSubsection, String aName, + String bSection, String bSubsection, String bName) { + int c = compareIgnoreCase(aSection, bSection); + if (c != 0) + return c; + + if (aSubsection == null && bSubsection != null) + return -1; + if (aSubsection != null && bSubsection == null) + return 1; + if (aSubsection != null) { + c = compareWithCase(aSubsection, bSubsection); + if (c != 0) + return c; + } + + return compareIgnoreCase(aName, bName); + } + + private static class LineComparator implements Comparator { + public int compare(ConfigLine a, ConfigLine b) { + return compare2( + a.section, a.subsection, a.name, + b.section, b.subsection, b.name); + } + } } diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/StringUtils.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/StringUtils.java index 605f1705ef..f423f98e27 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/util/StringUtils.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/StringUtils.java @@ -120,6 +120,50 @@ public final class StringUtils { return true; } + /** + * Compare two strings, ignoring case. + *

+ * This method does not honor the JVM locale, but instead always behaves as + * though it is in the US-ASCII locale. + * + * @param a + * first string to compare. + * @param b + * second string to compare. + * @return negative, zero or positive if a sorts before, is equal to, or + * sorts after b. + */ + public static int compareIgnoreCase(String a, String b) { + for (int i = 0; i < a.length() && i < b.length(); i++) { + int d = toLowerCase(a.charAt(i)) - toLowerCase(b.charAt(i)); + if (d != 0) + return d; + } + return a.length() - b.length(); + } + + /** + * Compare two strings, honoring case. + *

+ * This method does not honor the JVM locale, but instead always behaves as + * though it is in the US-ASCII locale. + * + * @param a + * first string to compare. + * @param b + * second string to compare. + * @return negative, zero or positive if a sorts before, is equal to, or + * sorts after b. + */ + public static int compareWithCase(String a, String b) { + for (int i = 0; i < a.length() && i < b.length(); i++) { + int d = a.charAt(i) - b.charAt(i); + if (d != 0) + return d; + } + return a.length() - b.length(); + } + /** * Parse a string as a standard Git boolean value. See * {@link #toBooleanOrNull(String)}. -- 2.39.5