diff options
author | 2016-05-11 13:54:29 +0000 | |
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committer | 2016-05-12 10:45:42 +0000 | |
commit | 7f339de7feb071d790ecbca1c346244f5794a7e3 (patch) | |
tree | a72bf52a0173e3c79ed71ac9d0d41ad49a205412 /src/main/java/com | |
parent | 6dbcc2da5144ad819ef8d219977b4c2fd85852c0 (diff) |
Optimize hotspot in DependencySet.process().
--
MOS_MIGRATED_REVID=122050015
Diffstat (limited to 'src/main/java/com')
-rw-r--r-- | src/main/java/com/google/devtools/build/lib/util/DependencySet.java | 124 |
1 files changed, 52 insertions, 72 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/util/DependencySet.java b/src/main/java/com/google/devtools/build/lib/util/DependencySet.java index cb8994b3f0..a51e98649b 100644 --- a/src/main/java/com/google/devtools/build/lib/util/DependencySet.java +++ b/src/main/java/com/google/devtools/build/lib/util/DependencySet.java @@ -24,8 +24,6 @@ import java.nio.charset.StandardCharsets; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; -import java.util.regex.Matcher; -import java.util.regex.Pattern; /** * Representation of a set of file dependencies for a given output file. There @@ -49,10 +47,6 @@ import java.util.regex.Pattern; */ public final class DependencySet { - private static final Pattern DOTD_MERGED_LINE_SEPARATOR = Pattern.compile("\\\\[\n\r]+"); - private static final Pattern DOTD_LINE_SEPARATOR = Pattern.compile("[\n\r]+"); - private static final Pattern DOTD_DEP = Pattern.compile("(?:[^\\s\\\\]++|\\\\ |\\\\)+"); - /** * The set of dependent files that this DependencySet embodies. They are all * Path with the same FileSystem A tree set is used to ensure that we @@ -73,7 +67,7 @@ public final class DependencySet { public void setOutputFileName(String outputFileName) { this.outputFileName = outputFileName; } - + /** * Constructs a new empty DependencySet instance. */ @@ -130,71 +124,57 @@ public final class DependencySet { if (content.length > 0 && content[content.length - 1] != '\n') { throw new IOException("File does not end in a newline"); } - // true if there is a CR in the input. - boolean cr = content.length > 0 && content[0] == '\r'; - // true if there is more than one line in the input, not counting \-wrapped lines. - boolean multiline = false; - - byte prevByte = ' '; - for (int i = 1; i < content.length; i++) { - byte b = content[i]; - if (cr || b == '\r') { - // CR found, abort since our little loop here does not deal with CR/LFs. - cr = true; - break; - } - if (b == '\n') { - // Merge lines wrapped using backslashes. - if (prevByte == '\\') { - content[i] = ' '; - content[i - 1] = ' '; - } else { - multiline = true; - } - } - prevByte = b; - } - - if (!cr && content.length > 0 && content[content.length - 1] == '\n') { - content[content.length - 1] = ' '; - } - - String s = new String(content, StandardCharsets.UTF_8); - if (cr) { - s = DOTD_MERGED_LINE_SEPARATOR.matcher(s).replaceAll(" ").trim(); - multiline = true; - } - return process(s, multiline); - } - - private DependencySet process(String contents, boolean multiline) { - String[] lines; - if (!multiline) { - // Microoptimization: skip the usually unnecessary expensive-ish splitting step if there is - // only one target. This saves about 20% of CPU time. - lines = new String[] { contents }; - } else { - lines = DOTD_LINE_SEPARATOR.split(contents); - } - - for (String line : lines) { - // Split off output file name. - int pos = line.indexOf(':'); - if (pos == -1) { - continue; - } - outputFileName = line.substring(0, pos); - - String deps = line.substring(pos + 1); - - Matcher m = DOTD_DEP.matcher(deps); - while (m.find()) { - String token = m.group(); - // Process escaped spaces. - if (token.contains("\\ ")) { - token = token.replace("\\ ", " "); - } - addDependency(new PathFragment(token).normalize()); + int w = 0; + for (int r = 0; r < content.length; ++r) { + final byte c = content[r]; + switch (c) { + case ' ': + case '\n': + case '\r': + if (w > 0) { + String s = new String(content, 0, w, StandardCharsets.UTF_8); + addDependency(new PathFragment(s).normalize()); + w = 0; + } + break; + case ':': + // Normally this indicates the output file, but it might be part of a filename on Windows. + // Peek ahead at the next character. This is in bounds because we checked for a + // terminating newline above. + switch (content[r + 1]) { + case ' ': + case '\n': + case '\r': + if (w > 0) { + outputFileName = new String(content, 0, w, StandardCharsets.UTF_8); + w = 0; + } + continue; + default: + content[w++] = c; // copy to filename + continue; + } + case '\\': + // Peek ahead at the next character. This is in bounds because we checked for a + // terminating newline above. + switch (content[r + 1]) { + // Backslashes are taken literally except when followed by whitespace. + // See the Windows tests for some of the nonsense we have to tolerate. + case ' ': + content[w++] = ' '; // copy a space into the filename + ++r; // skip the space in the input + continue; + case '\n': + case '\r': + // Let the newline act as a terminator. Technically we could have an escaped newline + // with no adjacent space, but compilers don't seem to generate that. + continue; + default: + content[w++] = c; // copy to filename + continue; + } + default: + content[w++] = c; } } return this; |