[BUG] Crash when big txt file is previewed

[jesmrec]

Could be related with #3794

Steps to reproduce

1. Create a big txt file (~30MB)
2. In app, open it

Actual behaviour

Spinner of waiting... and finally a crash. Stacktrace:

Process: com.owncloud.android.debug, PID: 16420
                 java.lang.OutOfMemoryError: Failed to allocate a 16 byte allocation with 2240160 free bytes and 2187KB until OOM, target footprint 268435456, growth limit 268435456; giving up on allocation because <1% of heap free after GC.
                 	at android.text.MeasuredParagraph.<init>(MeasuredParagraph.java:129)
                 	at android.text.MeasuredParagraph.obtain(MeasuredParagraph.java:80)
                 	at android.text.MeasuredParagraph.buildForStaticLayoutInternal(MeasuredParagraph.java:596)
                 	at android.text.MeasuredParagraph.buildForStaticLayout(MeasuredParagraph.java:543)
                 	at android.text.PrecomputedText.createMeasuredParagraphs(PrecomputedText.java:526)
                 	at android.text.StaticLayout.generate(StaticLayout.java:886)
                 	at android.text.StaticLayout.<init>(StaticLayout.java:733)
                 	at android.text.StaticLayout.<init>(StaticLayout.java:0)
                 	at android.text.StaticLayout$Builder.build(StaticLayout.java:547)
                 	at android.widget.TextView.makeSingleLayout(TextView.java:11216)
                 	at android.widget.TextView.makeNewLayout(TextView.java:10992)
                 	at android.widget.TextView.onMeasure(TextView.java:11442)
                 	at androidx.appcompat.widget.AppCompatTextView.onMeasure(AppCompatTextView.java:615)
                 	at android.view.View.measure(View.java:29423)
                 	at android.widget.ScrollView.measureChildWithMargins(ScrollView.java:1533)
                 	at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
                 	at android.widget.ScrollView.onMeasure(ScrollView.java:474)
                 	at android.view.View.measure(View.java:29423)
                 	at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:735)
                 	at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:481)
                 	at android.view.View.measure(View.java:29423)
                 	at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:7068)
                 	at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
                 	at android.view.View.measure(View.java:29423)
                 	at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:7068)
                 	at androidx.coordinatorlayout.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:760)
                 	at androidx.coordinatorlayout.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:833)
                 	at android.view.View.measure(View.java:29423)
                 	at androidx.constraintlayout.widget.ConstraintLayout$Measurer.measure(ConstraintLayout.java:811)
                 	at androidx.constraintlayout.core.widgets.ConstraintWidgetContainer.measure(ConstraintWidgetContainer.java:632)
                 	at androidx.constraintlayout.core.widgets.analyzer.Direct.verticalSolvingPass(Direct.java:452)
                 	at androidx.constraintlayout.core.widgets.analyzer.Direct.solveVerticalMatchConstraint(Direct.java:750)
                 	at androidx.constraintlayout.core.widgets.analyzer.Direct.verticalSolvingPass(Direct.java:503)
                 	at androidx.constraintlayout.core.widgets.analyzer.Direct.verticalSolvingPass(Direct.java:542)
                 	at androidx.constraintlayout.core.widgets.analyzer.Direct.solvingPass(Direct.java:224)
                 	at androidx.constraintlayout.core.widgets.ConstraintWidgetContainer.layout(ConstraintWidgetContainer.java:693)
                 	at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.solveLinearSystem(BasicMeasure.java:160)
                 	at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.solverMeasure(BasicMeasure.java:291)
                 	at androidx.constraintlayout.core.widgets.ConstraintWidgetContainer.measure(ConstraintWidgetContainer.java:120)
                 	at androidx.constraintlayout.widget.ConstraintLayout.resolveSystem(ConstraintLayout.java:1594)
                 	at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1708)
                 	at android.view.View.measure(View.java:29423)
                 	at androidx.drawerlayout.widget.DrawerLayout.onMeasure(DrawerLayout.java:1156)
                 	at android.view.View.measure(View.java:29423)
                 	at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:7068)
                 	at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
                 	at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:145)
                 	at android.view.View.measure(View.java:29423)
                 	at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:7068)
09:48:23.297  I  Process is going to kill itself!
                 java.lang.Exception
                 	at android.os.Process.killProcess(Process.java:1495)
                 	at com.android.internal.os.RuntimeInit$KillApplicationHandler.uncaughtException(RuntimeInit.java:193)
                 	at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:1098)
                 	at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:1093)
                 	at java.lang.Thread.dispatchUncaughtException(Thread.java:3387)

Expected behaviour

File correctly opened

Reproducible with any Android version and backend.

[DeepDiver1975]

Confirmed on current master. Root cause: the text preview loads the entire file into memory and hands the whole string to a single TextView, with no size cap — a ~30MB txt OOMs while StaticLayout/TextView.onMeasure builds the layout (matches your trace).

Code path (owncloudApp/.../ui/preview/PreviewTextFragment.kt, master):

• TextLoadAsyncTask.doInBackground reads the full file into a StringWriter line-by-line — L290, L306-310.
• onPostExecute materializes it as one String — val text = String(result.buffer) L334.
• showPreviewText sets it all at once — textView.text = text L384.
• canBePreviewed (L426) gates only on mime type, never file size.

Fix direction:

• Cap what the preview loads/renders (read only the first N bytes/lines, or truncate the displayed string) and/or gate canBePreviewed/the load on a max size.
• Prefer a paginated/streamed view or a scroll-bounded RecyclerView over a single TextView for large files, so layout cost stays bounded.

Likely same root cause as the linked frozen-preview report (still open).

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