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Improving performance of adblocking code by utilizing stringbuilder

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This commit is contained in:
anthony restaino 2017-04-23 23:31:28 -04:00
parent f90e897995
commit 80ab4aff35
1 changed files with 63 additions and 14 deletions
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77
app/src/main/java/acr/browser/lightning/utils/AdBlock.java
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@ -147,29 +147,41 @@ public class AdBlock {
//noinspection IOResourceOpenedButNotSafelyClosed
reader = new BufferedReader(new InputStreamReader(
asset.open(BLOCKED_DOMAINS_LIST_FILE_NAME)));
StringBuilder lineBuilder = new StringBuilder();
String line;
long time = System.currentTimeMillis();
// TODO: 4/23/17 Improve performance by reading in on IO thread and then processing on worker thread
while ((line = reader.readLine()) != null) {
if (!line.isEmpty() && !line.startsWith(COMMENT)) {
line = line.replace(LOCAL_IP_V4, EMPTY)
.replace(LOCAL_IP_V4_ALT, EMPTY)
.replace(LOCAL_IP_V6, EMPTY)
.replace(TAB, EMPTY);
int comment = line.indexOf(COMMENT);
lineBuilder.append(line);
if (!isEmpty(lineBuilder) && !startsWith(lineBuilder, COMMENT)) {
replace(lineBuilder, LOCAL_IP_V4, EMPTY);
replace(lineBuilder, LOCAL_IP_V4_ALT, EMPTY);
replace(lineBuilder, LOCAL_IP_V6, EMPTY);
replace(lineBuilder, TAB, EMPTY);
int comment = lineBuilder.indexOf(COMMENT);
if (comment >= 0) {
line = line.substring(0, comment);
lineBuilder.replace(comment, lineBuilder.length(), EMPTY);
}
line = line.trim();
if (!line.isEmpty() && !line.equals(LOCALHOST)) {
while (line.contains(SPACE)) {
int space = line.indexOf(SPACE);
String host = line.substring(0, space);
trim(lineBuilder);
if (!isEmpty(lineBuilder) && !AdBlock.equals(lineBuilder, LOCALHOST)) {
while (contains(lineBuilder, SPACE)) {
int space = lineBuilder.indexOf(SPACE);
String host = lineBuilder.substring(0, space);
replace(lineBuilder, host, EMPTY);
mBlockedDomainsList.add(host.trim());
line = line.substring(space, line.length()).trim();
}
mBlockedDomainsList.add(line.trim());
if (lineBuilder.length() > 0) {
mBlockedDomainsList.add(lineBuilder.toString());
}
}
}
lineBuilder.setLength(0);
}
Log.d(TAG, "Loaded ad list in: " + (System.currentTimeMillis() - time) + " ms");
} catch (IOException e) {
Log.wtf(TAG, "Reading blocked domains list from file '"
+ BLOCKED_DOMAINS_LIST_FILE_NAME + "' failed.", e);
@ -179,4 +191,41 @@ public class AdBlock {
}
});
}
// TODO: 4/23/17 Move all these methods to a StringUtils class
private static void replace(@NonNull StringBuilder stringBuilder,
@NonNull String toReplace,
@NonNull String replacement) {
int index = stringBuilder.indexOf(toReplace);
if (index >= 0) {
stringBuilder.replace(index, index + toReplace.length(), replacement);
}
}
private static void trim(@NonNull StringBuilder stringBuilder) {
while (stringBuilder.indexOf(SPACE) == 0) {
stringBuilder.replace(0, 1, EMPTY);
}
while (stringBuilder.lastIndexOf(SPACE) == (stringBuilder.length() - 1)) {
stringBuilder.replace(stringBuilder.length() - 1, stringBuilder.length(), EMPTY);
}
}
private static boolean isEmpty(@NonNull StringBuilder stringBuilder) {
return stringBuilder.length() == 0;
}
private static boolean startsWith(@NonNull StringBuilder stringBuilder, @NonNull String start) {
return stringBuilder.indexOf(start) == 0;
}
private static boolean contains(@NonNull StringBuilder stringBuilder, @NonNull String contains) {
return stringBuilder.indexOf(contains) >= 0;
}
private static boolean equals(@NonNull StringBuilder stringBuilder, @NonNull String equal) {
int index = stringBuilder.indexOf(equal);
return index >= 0 && stringBuilder.length() == equal.length();
}
}