🛠️ Improve EPUB, add cancellation

* Improved EPUB parser
* Added coroutine cancellation points to parsers

app/src/main/java/ua/acclorite/book_story/data/parser/DocumentParser.kt

@@ -0,0 +1,52 @@
+package ua.acclorite.book_story.data.parser
+
+import kotlinx.coroutines.yield
+import org.jsoup.nodes.Document
+import javax.inject.Inject
+
+class DocumentParser @Inject constructor() {
+    /**
+     * Parses document to get it's text.
+     * If [fragment] is not null, searches document for specific [fragment].
+     *
+     * @return Parsed text line by line.
+     */
+    suspend fun Document.parseDocument(fragment: String?): List<String> {
+        val lines = mutableListOf<String>()
+
+        yield()
+
+        body()
+            .select("p")
+            .apply {
+                forEach { element ->
+                    yield()
+
+                    val cleanedText = element.html().replace(Regex("\\n+"), " ")
+                    element.html(cleanedText)
+                }
+
+                append("\n")
+            }
+
+        yield()
+
+        body()
+            .run {
+                fragment?.let { return@run getElementById(it) ?: this }
+                this
+            }
+            .wholeText()
+            .lines()
+            .forEach { line ->
+                yield()
+                if (line.isNotBlank()) {
+                    lines.add(line.trim())
+                }
+            }
+
+        yield()
+
+        return lines
+    }
+}

app/src/main/java/ua/acclorite/book_story/data/parser/epub/EpubTextParser.kt

@@ -4,8 +4,10 @@ import android.net.Uri
 import android.util.Log
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import kotlinx.coroutines.yield
 import org.jsoup.Jsoup
 import ua.acclorite.book_story.R
+import ua.acclorite.book_story.data.parser.DocumentParser
 import ua.acclorite.book_story.data.parser.TextParser
 import ua.acclorite.book_story.domain.model.Chapter
 import ua.acclorite.book_story.domain.model.ChapterWithText
@@ -18,7 +20,9 @@ import javax.inject.Inject
 
 private const val EPUB_TAG = "EPUB Parser"
 
-class EpubTextParser @Inject constructor() : TextParser {
+class EpubTextParser @Inject constructor(
+    private val documentParser: DocumentParser
+) : TextParser {
 
     override suspend fun parse(file: File): Resource<List<ChapterWithText>> {
         Log.i(EPUB_TAG, "Started EPUB parsing: ${file.name}.")
@@ -26,8 +30,12 @@ class EpubTextParser @Inject constructor() : TextParser {
         return try {
             val chapters = mutableListOf<ChapterWithText>()
 
+            yield()
+
             withContext(Dispatchers.IO) {
                 ZipFile(file).use { zip ->
+                    yield()
+
                     zip.entries().asSequence().find { entry ->
                         entry.name.endsWith("toc.ncx", ignoreCase = true)
                     }.apply {
@@ -45,10 +53,14 @@ class EpubTextParser @Inject constructor() : TextParser {
 
                             chapters.addAll(this)
                         }
+
+                        yield()
                     }
                 }
             }
 
+            yield()
+
             if (chapters.isEmpty()) {
                 return Resource.Error(UIText.StringResource(R.string.error_file_empty))
             }
@@ -71,12 +83,16 @@ class EpubTextParser @Inject constructor() : TextParser {
      *
      * @return Null if could not parse.
      */
-    private fun parseWithoutToc(zip: ZipFile): List<ChapterWithText>? {
+    private suspend fun parseWithoutToc(zip: ZipFile): List<ChapterWithText>? {
         val chapters = mutableListOf<ChapterWithText>()
         var chapterTextIndex = -1
         var chapterIndex = 1
 
+        yield()
+
         zip.entries().asSequence().sortedBy { it.name }.forEach { entry ->
+            yield()
+
             if (
                 !entry.name.endsWith(".xhtml")
                 && !entry.name.endsWith(".html")
@@ -85,7 +101,13 @@ class EpubTextParser @Inject constructor() : TextParser {
                 || entry.name.endsWith("container.xml")
             ) return@forEach
 
-            val chapter = zip.parseDocument(entry = entry, fragment = null)
+            val content = zip.getInputStream(entry)
+                .bufferedReader()
+                .use {
+                    it.readText()
+                }
+
+            val chapter = documentParser.run { Jsoup.parse(content).parseDocument(fragment = null) }
             if (chapter.isEmpty()) {
                 Log.w(EPUB_TAG, "Chapter ${entry.name} is empty.")
                 return@forEach
@@ -106,6 +128,8 @@ class EpubTextParser @Inject constructor() : TextParser {
             chapterIndex++
         }
 
+        yield()
+
         if (chapters.isEmpty()) {
             Log.e(EPUB_TAG, "Could not parse file without toc.ncx")
             return null
@@ -119,7 +143,7 @@ class EpubTextParser @Inject constructor() : TextParser {
      *
      * @return Null if could not parse toc.ncx.
      */
-    private fun parseWithToc(tocEntry: ZipEntry, zip: ZipFile): List<ChapterWithText>? {
+    private suspend fun parseWithToc(tocEntry: ZipEntry, zip: ZipFile): List<ChapterWithText>? {
         Log.i(EPUB_TAG, "TOC Entry: ${tocEntry.name}")
 
         val chapters = mutableListOf<ChapterWithText>()
@@ -127,12 +151,18 @@ class EpubTextParser @Inject constructor() : TextParser {
         var chapterTextIndex = -1
         var chapterIndex = 1
 
-        val tocContent = zip.getInputStream(tocEntry)
+        yield()
-            .bufferedReader()
+
-            .use { it.readText() }
+        val tocContent = withContext(Dispatchers.IO) {
+            zip.getInputStream(tocEntry)
+        }.bufferedReader().use { it.readText() }
         val tocDocument = Jsoup.parse(tocContent)
 
+        yield()
+
         tocDocument.select("navPoint").forEach { navPoint ->
+            yield()
+
             val chapterTitle = navPoint.selectFirst("navLabel > text")?.text()?.trim()
                 ?: "Chapter $chapterIndex"
             val chapterSrc = navPoint.selectFirst("content")?.attr("src")?.trim()
@@ -154,12 +184,19 @@ class EpubTextParser @Inject constructor() : TextParser {
                     return null
                 }
 
-                val chapter = zip.parseDocument(
+                val content = zip.getInputStream(this)
-                    entry = this,
+                    .bufferedReader()
+                    .use {
+                        it.readText()
+                    }
+
+                val chapter = documentParser.run {
+                    Jsoup.parse(content).parseDocument(
                         fragment = chapterSrc.second
                     ).dropWhile {
                         it == chapterTitle // Remove chapter title if present
                     }
+                }
                 if (chapter.isEmpty()) {
                     Log.w(EPUB_TAG, "Chapter $chapterTitle is empty.")
                     emptyChapters += 1
@@ -182,6 +219,8 @@ class EpubTextParser @Inject constructor() : TextParser {
             }
         }
 
+        yield()
+
         if (chapters.isEmpty()) {
             Log.e(EPUB_TAG, "Could not parse text with toc.ncx")
             return null
@@ -194,44 +233,4 @@ class EpubTextParser @Inject constructor() : TextParser {
 
         return chapters
     }
-
-    /**
-     * Parses [entry] to get it's text.
-     *
-     * @return Parsed text line by line. Can have line break issues due to bad [entry] formatting.
-     */
-    private fun ZipFile.parseDocument(entry: ZipEntry, fragment: String?): List<String> {
-        val lines = mutableListOf<String>()
-        val content = getInputStream(entry)
-            .bufferedReader()
-            .use {
-                it.readText()
-            }
-
-        val document = Jsoup.parse(content)
-        document
-            .body()
-            .select("p")
-            .append("\n")
-            .forEach { element ->
-                val cleanedText = element.html().replace(Regex("\\n+"), " ")
-                element.html(cleanedText)
-            }
-
-        document
-            .body()
-            .run {
-                fragment?.let { return@run getElementById(it) ?: this }
-                this
-            }
-            .wholeText()
-            .lines()
-            .forEach { line ->
-                if (line.isNotBlank()) {
-                    lines.add(line.trim())
-                }
-            }
-
-        return lines
-    }
 }

app/src/main/java/ua/acclorite/book_story/data/parser/fb2/Fb2TextParser.kt

@@ -3,6 +3,7 @@ package ua.acclorite.book_story.data.parser.fb2
 import android.util.Log
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import kotlinx.coroutines.yield
 import org.w3c.dom.Element
 import org.w3c.dom.NodeList
 import ua.acclorite.book_story.R
@@ -38,11 +39,15 @@ class Fb2TextParser @Inject constructor() : TextParser {
                 )
             }
 
+            yield()
+
             val unformattedLines = mutableListOf<String>()
             val bodyNode = bodyNodes.item(0) as Element
             val paragraphNodes = bodyNode.getElementsByTagName("p")
 
             for (element in paragraphNodes.asList()) {
+                yield()
+
                 if (element.textContent.isBlank()) {
                     continue
                 }
@@ -52,9 +57,13 @@ class Fb2TextParser @Inject constructor() : TextParser {
                 )
             }
 
+            yield()
+
             val lines = mutableListOf<String>()
             unformattedLines.forEachIndexed { index, string ->
                 try {
+                    yield()
+
                     val line = string.trim()
 
                     if (index == 0) {
@@ -96,10 +105,15 @@ class Fb2TextParser @Inject constructor() : TextParser {
                 }
             }
 
+            yield()
+
             lines.forEach { line ->
+                yield()
                 formattedLines.add(line.trim())
             }
 
+            yield()
+
             if (formattedLines.isEmpty()) {
                 return Resource.Error(UIText.StringResource(R.string.error_file_empty))
             }

app/src/main/java/ua/acclorite/book_story/data/parser/htm/HtmTextParser.kt

@@ -1,8 +1,10 @@
 package ua.acclorite.book_story.data.parser.htm
 
 import android.util.Log
+import kotlinx.coroutines.yield
 import org.jsoup.Jsoup
 import ua.acclorite.book_story.R
+import ua.acclorite.book_story.data.parser.DocumentParser
 import ua.acclorite.book_story.data.parser.TextParser
 import ua.acclorite.book_story.domain.model.Chapter
 import ua.acclorite.book_story.domain.model.ChapterWithText
@@ -13,26 +15,17 @@ import javax.inject.Inject
 
 private const val HTM_TAG = "HTM Parser"
 
-class HtmTextParser @Inject constructor() : TextParser {
+class HtmTextParser @Inject constructor(
+    private val documentParser: DocumentParser
+) : TextParser {
 
     override suspend fun parse(file: File): Resource<List<ChapterWithText>> {
         Log.i(HTM_TAG, "Started HTM parsing: ${file.name}.")
 
         return try {
-            val lines = mutableListOf<String>()
+            val lines = documentParser.run { Jsoup.parse(file).parseDocument(null) }
 
-            val document = Jsoup.parse(file)
+            yield()
-            document.select("p").append("\n")
-            document.select("head > title").remove()
-
-            document
-                .wholeText()
-                .lines()
-                .forEach { line ->
-                    if (line.isNotBlank()) {
-                        lines.add(line.trim())
-                    }
-                }
 
             if (lines.isEmpty()) {
                 return Resource.Error(UIText.StringResource(R.string.error_file_empty))

app/src/main/java/ua/acclorite/book_story/data/parser/html/HtmlTextParser.kt

@@ -1,8 +1,10 @@
 package ua.acclorite.book_story.data.parser.html
 
 import android.util.Log
+import kotlinx.coroutines.yield
 import org.jsoup.Jsoup
 import ua.acclorite.book_story.R
+import ua.acclorite.book_story.data.parser.DocumentParser
 import ua.acclorite.book_story.data.parser.TextParser
 import ua.acclorite.book_story.domain.model.Chapter
 import ua.acclorite.book_story.domain.model.ChapterWithText
@@ -13,26 +15,17 @@ import javax.inject.Inject
 
 private const val HTML_TAG = "HTML Parser"
 
-class HtmlTextParser @Inject constructor() : TextParser {
+class HtmlTextParser @Inject constructor(
+    private val documentParser: DocumentParser
+) : TextParser {
 
     override suspend fun parse(file: File): Resource<List<ChapterWithText>> {
         Log.i(HTML_TAG, "Started HTML parsing: ${file.name}.")
 
         return try {
-            val lines = mutableListOf<String>()
+            val lines = documentParser.run { Jsoup.parse(file).parseDocument(null) }
 
-            val document = Jsoup.parse(file)
+            yield()
-            document.select("p").append("\n")
-            document.select("head > title").remove()
-
-            document
-                .wholeText()
-                .lines()
-                .forEach { line ->
-                    if (line.isNotBlank()) {
-                        lines.add(line.trim())
-                    }
-                }
 
             if (lines.isEmpty()) {
                 return Resource.Error(UIText.StringResource(R.string.error_file_empty))

app/src/main/java/ua/acclorite/book_story/data/parser/pdf/PdfTextParser.kt

@@ -3,6 +3,7 @@ package ua.acclorite.book_story.data.parser.pdf
 import android.util.Log
 import com.tom_roush.pdfbox.pdmodel.PDDocument
 import com.tom_roush.pdfbox.text.PDFTextStripper
+import kotlinx.coroutines.yield
 import ua.acclorite.book_story.R
 import ua.acclorite.book_story.data.parser.TextParser
 import ua.acclorite.book_story.domain.model.ChapterWithText
@@ -20,18 +21,24 @@ class PdfTextParser @Inject constructor() : TextParser {
         Log.i(PDF_TAG, "Started PDF parsing: ${file.name}.")
 
         return try {
-            val document = PDDocument.load(file)
+            yield()
-            val strings = mutableListOf<String>()
+
+            val oldText: String
 
             val pdfStripper = PDFTextStripper()
             pdfStripper.paragraphStart = "</br>"
 
-            val oldText = pdfStripper.getText(document)
+            PDDocument.load(file).use {
+                oldText = pdfStripper.getText(it)
                     .replace("\r", "")
+            }
 
-            document.close()
+            yield()
 
+            val strings = mutableListOf<String>()
             val text = oldText.filterIndexed { index, c ->
+                yield()
+
                 if (c == ' ') {
                     oldText[index - 1] != ' '
                 } else {
@@ -39,12 +46,18 @@ class PdfTextParser @Inject constructor() : TextParser {
                 }
             }
 
+            yield()
+
             val unformattedLines = text.split("${pdfStripper.paragraphStart}|\\n".toRegex())
                 .filter { it.isNotBlank() }
 
+            yield()
+
             val lines = mutableListOf<String>()
             unformattedLines.forEachIndexed { index, string ->
                 try {
+                    yield()
+
                     val line = string.trim()
 
                     if (index == 0) {
@@ -86,10 +99,15 @@ class PdfTextParser @Inject constructor() : TextParser {
                 }
             }
 
+            yield()
+
             lines.forEach { line ->
+                yield()
                 strings.add(line.trim())
             }
 
+            yield()
+
             if (strings.isEmpty()) {
                 return Resource.Error(UIText.StringResource(R.string.error_file_empty))
             }

app/src/main/java/ua/acclorite/book_story/data/parser/txt/TxtTextParser.kt

@@ -3,6 +3,7 @@ package ua.acclorite.book_story.data.parser.txt
 import android.util.Log
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import kotlinx.coroutines.yield
 import ua.acclorite.book_story.R
 import ua.acclorite.book_story.data.parser.TextParser
 import ua.acclorite.book_story.domain.model.ChapterWithText
@@ -34,6 +35,8 @@ class TxtTextParser @Inject constructor() : TextParser {
                 }
             }
 
+            yield()
+
             if (lines.isEmpty()) {
                 return Resource.Error(UIText.StringResource(R.string.error_file_empty))
             }