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Replaced custom SpannableBuilder with ReverseSpannableStringBuilder

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Background:
The usage and maintaining of SpannableBuilder is reduced by using
a good-old-SpannableStringBuilder directly but making sure its spans are
reversed.

The implementation is credited Uncodin/bypass
This commit is contained in:
Cyrus Bakhtiari-Haftlang 2018-07-12 09:28:47 +02:00
parent b0e548ce50
commit 91c8115533
8 changed files with 77 additions and 280 deletions
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42
library/src/main/java/ru/noties/markwon/ReverseSpannableStringBuilder.java Normal file
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@ -0,0 +1,42 @@
package ru.noties.markwon;
import android.text.SpannableStringBuilder;
/**
* Copied as is from @see <a href = "https://github.com/Uncodin/bypass/blob/master/platform/android/
* library/src/in/uncod/android/bypass/ReverseSpannableStringBuilder.java">Uncodin/bypass</a>
*/
public class ReverseSpannableStringBuilder extends SpannableStringBuilder {
public ReverseSpannableStringBuilder() {
super();
}
public ReverseSpannableStringBuilder(CharSequence text, int start, int end) {
super(text, start, end);
}
@Override
public <T> T[] getSpans(int queryStart, int queryEnd, Class<T> kind) {
T[] ret = super.getSpans(queryStart, queryEnd, kind);
reverse(ret);
return ret;
}
private static void reverse(Object[] arr) {
if (arr == null) {
return;
}
int i = 0;
int j = arr.length - 1;
Object tmp;
while (j > i) {
tmp = arr[j];
arr[j] = arr[i];
arr[i] = tmp;
j--;
i++;
}
}
}

241
library/src/main/java/ru/noties/markwon/SpannableBuilder.java
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@ -1,241 +0,0 @@
package ru.noties.markwon;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Iterator;
/**
* This class is used to _revert_ order of applied spans. Original SpannableStringBuilder
* is using an array to store all the information about spans. So, a span that is added first
* will be drawn first, which leads to subtle bugs (spans receive wrong `x` values when
* requested to draw itself)
*
* @since 1.0.1
*/
@SuppressWarnings({"WeakerAccess", "unused"})
public class SpannableBuilder {
// do not implement CharSequence (or any of Spanned interfaces)
// we will be using SpannableStringBuilder anyway as a backing store
// as it has tight connection with system (implements some hidden methods, etc)
private final SpannableStringBuilder builder;
// actually we might be just using ArrayList
private final Deque<Span> spans = new ArrayDeque<>(8);
public SpannableBuilder() {
this("");
}
public SpannableBuilder(@NonNull CharSequence cs) {
this.builder = new SpannableStringBuilderImpl(cs.toString());
copySpans(0, cs);
}
/**
* Additional method that takes a String, which is proven to NOT contain any spans
*
* @param text String to append
* @return this instance
*/
@NonNull
public SpannableBuilder append(@NonNull String text) {
builder.append(text);
return this;
}
@NonNull
public SpannableBuilder append(char c) {
builder.append(c);
return this;
}
@NonNull
public SpannableBuilder append(@NonNull CharSequence cs) {
copySpans(length(), cs);
builder.append(cs.toString());
return this;
}
@NonNull
public SpannableBuilder append(@NonNull CharSequence cs, @NonNull Object span) {
final int length = length();
append(cs);
setSpan(span, length);
return this;
}
@NonNull
public SpannableBuilder append(@NonNull CharSequence cs, @NonNull Object span, int flags) {
final int length = length();
append(cs);
setSpan(span, length, length(), flags);
return this;
}
@NonNull
public SpannableBuilder setSpan(@NonNull Object span, int start) {
return setSpan(span, start, length());
}
@NonNull
public SpannableBuilder setSpan(@NonNull Object span, int start, int end) {
return setSpan(span, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
@NonNull
public SpannableBuilder setSpan(@NonNull Object span, int start, int end, int flags) {
spans.push(new Span(span, start, end, flags));
return this;
}
public int length() {
return builder.length();
}
public char charAt(int index) {
return builder.charAt(index);
}
public char lastChar() {
return builder.charAt(length() - 1);
}
@NonNull
public CharSequence removeFromEnd(int start) {
// this method is not intended to be used by clients
// it's a workaround to support tables
final int end = length();
// as we do not expose builder and do no apply spans to it, we are safe to NOT to convert to String
final SpannableStringBuilderImpl impl = new SpannableStringBuilderImpl(builder.subSequence(start, end));
final Iterator<Span> iterator = spans.iterator();
Span span;
while (iterator.hasNext() && ((span = iterator.next())) != null) {
if (span.start >= start && span.end <= end) {
impl.setSpan(span.what, span.start - start, span.end - start, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
iterator.remove();
}
}
builder.replace(start, end, "");
return impl;
}
@Override
@NonNull
public String toString() {
return builder.toString();
}
@NonNull
public CharSequence text() {
// okay, in order to not allow external modification and keep our spans order
// we should not return our builder
//
// plus, if this method was called -> all spans would be applied, which potentially
// breaks the order that we intend to use
// so, we will defensively copy builder
// as we do not expose builder and do no apply spans to it, we are safe to NOT to convert to String
final SpannableStringBuilderImpl impl = new SpannableStringBuilderImpl(builder);
for (Span span : spans) {
impl.setSpan(span.what, span.start, span.end, span.flags);
}
// now, let's remove trailing newLines (so small amounts of text are displayed correctly)
// @since 1.0.2
final int length = impl.length();
if (length > 0) {
int amount = 0;
for (int i = length - 1; i >= 0; i--) {
if (Character.isWhitespace(impl.charAt(i))) {
amount += 1;
} else {
break;
}
}
if (amount > 0) {
impl.replace(length - amount, length, "");
}
}
return impl;
}
private void copySpans(final int index, @Nullable CharSequence cs) {
// we must identify already reversed Spanned...
// and (!) iterate backwards when adding (to preserve order)
if (cs instanceof Spanned) {
final Spanned spanned = (Spanned) cs;
final boolean reverse = spanned instanceof SpannedReversed;
final Object[] spans = spanned.getSpans(0, spanned.length(), Object.class);
final int length = spans != null
? spans.length
: 0;
if (length > 0) {
if (reverse) {
Object o;
for (int i = length - 1; i >= 0; i--) {
o = spans[i];
setSpan(
o,
index + spanned.getSpanStart(o),
index + spanned.getSpanEnd(o),
spanned.getSpanFlags(o)
);
}
} else {
Object o;
for (int i = 0; i < length; i++) {
o = spans[i];
setSpan(
o,
index + spanned.getSpanStart(o),
index + spanned.getSpanEnd(o),
spanned.getSpanFlags(o)
);
}
}
}
}
}
static class Span {
final Object what;
int start;
int end;
final int flags;
Span(@NonNull Object what, int start, int end, int flags) {
this.what = what;
this.start = start;
this.end = end;
this.flags = flags;
}
}
}

13
library/src/main/java/ru/noties/markwon/SpannableStringBuilderImpl.java
View File

@ -1,13 +0,0 @@
package ru.noties.markwon;
import android.text.SpannableStringBuilder;
/**
* @since 1.0.1
*/
class SpannableStringBuilderImpl extends SpannableStringBuilder implements SpannedReversed {
SpannableStringBuilderImpl(CharSequence text) {
super(text);
}
}

9
library/src/main/java/ru/noties/markwon/SpannedReversed.java
View File

@ -1,9 +0,0 @@
package ru.noties.markwon;
import android.text.Spanned;
/**
* @since 1.0.1
*/
interface SpannedReversed extends Spanned {
}

28
library/src/main/java/ru/noties/markwon/renderer/SpannableMarkdownVisitor.java
View File

@ -2,6 +2,7 @@ package ru.noties.markwon.renderer;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.TextUtils;
@ -39,7 +40,7 @@ import java.util.ArrayList;
import java.util.Deque;
import java.util.List;
import ru.noties.markwon.SpannableBuilder;
import ru.noties.markwon.ReverseSpannableStringBuilder;
import ru.noties.markwon.SpannableConfiguration;
import ru.noties.markwon.SpannableFactory;
import ru.noties.markwon.renderer.html.SpannableHtmlParser;
@ -52,7 +53,7 @@ import ru.noties.markwon.tasklist.TaskListItem;
public class SpannableMarkdownVisitor extends AbstractVisitor {
private final SpannableConfiguration configuration;
private final SpannableBuilder builder;
private final SpannableStringBuilder builder;
private final Deque<HtmlInlineItem> htmlInlineItems;
private final SpannableTheme theme;
@ -67,7 +68,7 @@ public class SpannableMarkdownVisitor extends AbstractVisitor {
public SpannableMarkdownVisitor(
@NonNull SpannableConfiguration configuration,
@NonNull SpannableBuilder builder
@NonNull SpannableStringBuilder builder
) {
this.configuration = configuration;
this.builder = builder;
@ -363,10 +364,9 @@ public class SpannableMarkdownVisitor extends AbstractVisitor {
if (pendingTableRow == null) {
pendingTableRow = new ArrayList<>(2);
}
pendingTableRow.add(new TableRowSpan.Cell(
tableCellAlignment(cell.getAlignment()),
builder.removeFromEnd(length)
removeFromEnd(length)
));
tableRowIsHeader = cell.isHeader();
@ -378,6 +378,22 @@ public class SpannableMarkdownVisitor extends AbstractVisitor {
return handled;
}
@NonNull
private CharSequence removeFromEnd(int start) {
// this method is not intended to be used by clients
// it's a workaround to support tables
final int end = builder.length();
// as we do not expose builder and do no apply spans to it, we are safe to NOT to convert to String
final SpannableStringBuilder impl = new ReverseSpannableStringBuilder(builder, start, end);
builder.delete(start, end);
return impl;
}
@Override
public void visit(Paragraph paragraph) {
final boolean inTightList = isInTightList(paragraph);
@ -504,7 +520,7 @@ public class SpannableMarkdownVisitor extends AbstractVisitor {
private void newLine() {
if (builder.length() > 0
&& '\n' != builder.lastChar()) {
&& '\n' != builder.charAt(builder.length() - 1)) {
builder.append('\n');
}
}

7
library/src/main/java/ru/noties/markwon/renderer/SpannableRenderer.java
View File

@ -1,18 +1,19 @@
package ru.noties.markwon.renderer;
import android.support.annotation.NonNull;
import android.text.SpannableStringBuilder;
import org.commonmark.node.Node;
import ru.noties.markwon.SpannableBuilder;
import ru.noties.markwon.ReverseSpannableStringBuilder;
import ru.noties.markwon.SpannableConfiguration;
public class SpannableRenderer {
@NonNull
public CharSequence render(@NonNull SpannableConfiguration configuration, @NonNull Node node) {
final SpannableBuilder builder = new SpannableBuilder();
final SpannableStringBuilder builder = new ReverseSpannableStringBuilder();
node.accept(new SpannableMarkdownVisitor(configuration, builder));
return builder.text();
return builder;
}
}

10
sample-custom-extension/src/main/java/ru/noties/markwon/sample/extension/IconVisitor.java
View File

@ -1,25 +1,25 @@
package ru.noties.markwon.sample.extension;
import android.support.annotation.NonNull;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.TextUtils;
import android.widget.TextView;
import org.commonmark.node.CustomNode;
import ru.noties.markwon.SpannableBuilder;
import ru.noties.markwon.SpannableConfiguration;
import ru.noties.markwon.renderer.SpannableMarkdownVisitor;
@SuppressWarnings("WeakerAccess")
public class IconVisitor extends SpannableMarkdownVisitor {
private final SpannableBuilder builder;
private final SpannableStringBuilder builder;
private final IconSpanProvider iconSpanProvider;
public IconVisitor(
@NonNull SpannableConfiguration configuration,
@NonNull SpannableBuilder builder,
@NonNull SpannableStringBuilder builder,
@NonNull IconSpanProvider iconSpanProvider
) {
super(configuration, builder);
@ -51,7 +51,7 @@ public class IconVisitor extends SpannableMarkdownVisitor {
final int length = builder.length();
builder.append(name);
builder.setSpan(iconSpanProvider.provide(name, color, size), length);
builder.setSpan(iconSpanProvider.provide(name, color, size), length, length, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
builder.append(' ');
return true;

7
sample-custom-extension/src/main/java/ru/noties/markwon/sample/extension/MainActivity.java
View File

@ -3,6 +3,7 @@ package ru.noties.markwon.sample.extension;
import android.app.Activity;
import android.graphics.Typeface;
import android.os.Bundle;
import android.text.SpannableStringBuilder;
import android.widget.TextView;
import org.commonmark.ext.gfm.strikethrough.StrikethroughExtension;
@ -12,7 +13,7 @@ import org.commonmark.parser.Parser;
import java.util.Arrays;
import ru.noties.markwon.SpannableBuilder;
import ru.noties.markwon.ReverseSpannableStringBuilder;
import ru.noties.markwon.SpannableConfiguration;
import ru.noties.markwon.spans.SpannableTheme;
import ru.noties.markwon.tasklist.TaskListExtension;
@ -45,7 +46,7 @@ public class MainActivity extends Activity {
final Node node = parser.parse(markdown);
final SpannableBuilder builder = new SpannableBuilder();
final SpannableStringBuilder builder = new ReverseSpannableStringBuilder();
// please note that here I am passing `0` as fallback it means that if markdown references
// unknown icon, it will try to load fallback one and will fail with ResourceNotFound. It's
@ -70,6 +71,6 @@ public class MainActivity extends Activity {
node.accept(visitor);
// apply
textView.setText(builder.text());
textView.setText(builder);
}
}