Answer a right click the way a long press is answered (#930)

A pointer asks a row for its menu with the secondary button -- a right
click, or a two-finger tap -- and nothing answered it.
`combinedClickable` reads any button's press as an ordinary tap and
finds a long press only by timing a held finger, so a right click did
what a left click does.

A `View` answers it by itself -- badly: the menu came from the row under
the pointer but acted on the field only the long press wrote, opening
against whichever row was held last. Compose changed the symptom, not
the cause.

So the press is handed to the long press's lambda, watched on the
initial pass and consumed so the click never lands -- module rows,
apps in a scope, contributors on the home screen. Nothing changes for a
finger.

Fixes #644

Author: JingMatrix

manager-ui/src/main/kotlin/org/matrix/vector/ui/ContextClick.kt

@@ -0,0 +1,58 @@
+package org.matrix.vector.ui
+
+import androidx.compose.foundation.combinedClickable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.input.pointer.PointerEventPass
+import androidx.compose.ui.input.pointer.isSecondaryPressed
+import androidx.compose.ui.input.pointer.pointerInput
+
+/**
+ * A row's whole gesture set: tap it, hold it — and, from a mouse or a touchpad, right-click it.
+ *
+ * A tablet with a keyboard case is a pointer device, and the way to ask a row for its menu with a
+ * pointer is the secondary button: a right click, or a two-finger tap on the touchpad. Compose has
+ * no notion of that gesture. `combinedClickable` reads a press from any button as the beginning of
+ * an ordinary tap and reaches [onLongClick] only by timing a held finger, so on a touchpad every
+ * row here answered a right click by doing whatever a left click does, and whatever the hold was
+ * for could not be reached at all. The View-based manager never had to say any of this: a `View`
+ * opens its registered context menu on a secondary press by itself, which is why the gesture worked
+ * before the manager was written in Compose.
+ *
+ * So the secondary press is caught here and handed to [onLongClick] — the same action, because the
+ * two gestures mean the same thing, one asked with a finger and one asked with a pointer.
+ */
+fun Modifier.contextClickable(onClick: () -> Unit, onLongClick: (() -> Unit)? = null): Modifier =
+    combinedClickable(onClick = onClick, onLongClick = onLongClick)
+        .then(if (onLongClick == null) Modifier else Modifier.onSecondaryPress(onLongClick))
+
+/**
+ * The secondary button's press, taken before anything underneath can read it as a tap.
+ *
+ * On [Initial][PointerEventPass.Initial], the pass that runs before the one `combinedClickable`
+ * listens on — the same way [org.matrix.vector.ui.navigation.PanelBar] gets ahead of the item it
+ * wraps — and every event of the press is consumed, which is what keeps the click from landing:
+ * foundation asks for a press nothing else has taken, and for a release nothing else has taken.
+ *
+ * The action runs on the way down rather than on the release, matching the platform: a right click
+ * on a `View` opens its context menu the moment the button goes down. It runs on the first event
+ * that reports the button held rather than on the press event alone, because a pointer that
+ * announces its buttons a moment after it announces the touch would otherwise be missed.
+ */
+private fun Modifier.onSecondaryPress(action: () -> Unit): Modifier =
+    pointerInput(action) {
+        awaitPointerEventScope {
+            var fired = false
+            while (true) {
+                val event = awaitPointerEvent(PointerEventPass.Initial)
+                if (!event.buttons.isSecondaryPressed) {
+                    fired = false
+                    continue
+                }
+                event.changes.forEach { it.consume() }
+                if (!fired) {
+                    fired = true
+                    action()
+                }
+            }
+        }
+    }

manager-ui/src/main/kotlin/org/matrix/vector/ui/ModuleRow.kt

@@ -4,7 +4,6 @@ import androidx.compose.foundation.ExperimentalFoundationApi
 import androidx.compose.foundation.background
 import androidx.compose.foundation.basicMarquee
 import androidx.compose.foundation.clickable
-import androidx.compose.foundation.combinedClickable
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.IntrinsicSize
@@ -135,7 +134,7 @@ fun ModuleRow(
         Column(
             modifier =
                 if (onIconClick != null)
-                    Modifier.combinedClickable(onClick = onIconClick, onLongClick = onIconLongClick)
+                    Modifier.contextClickable(onClick = onIconClick, onLongClick = onIconLongClick)
                 else Modifier,
             // Against the text, not centred over the badge: the badge below is wider than the icon,
             // so centring left a gap between the icon and the edge the names all start from.
@@ -175,7 +174,7 @@ fun ModuleRow(
             Modifier.weight(1f)
                 .then(
                     if (onClick != null)
-                        Modifier.combinedClickable(onClick = onClick, onLongClick = onLongClick)
+                        Modifier.contextClickable(onClick = onClick, onLongClick = onLongClick)
                     else Modifier
                 )
         ) {

manager/src/main/kotlin/org/matrix/vector/manager/ui/components/CommitTimeline.kt

@@ -5,7 +5,7 @@ import androidx.compose.foundation.background
 import androidx.compose.foundation.border
 import androidx.compose.foundation.ExperimentalFoundationApi
 import androidx.compose.foundation.clickable
-import androidx.compose.foundation.combinedClickable
+import org.matrix.vector.ui.contextClickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -212,7 +212,7 @@ fun CommitRow(
                     // means "open this commit", and a long press on a subject line has no obvious
                     // subject; a long press on a name plainly means *that name*.
                     modifier =
-                        Modifier.combinedClickable(
+                        Modifier.contextClickable(
                             onClick = { onOpenCommit(commit) },
                             onLongClick = {
                                 haptics.performHapticFeedback(HapticFeedbackType.LongPress)

manager/src/main/kotlin/org/matrix/vector/manager/ui/screens/home/HomeScreen.kt

@@ -10,7 +10,7 @@ import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.ExperimentalFoundationApi
-import androidx.compose.foundation.combinedClickable
+import org.matrix.vector.ui.contextClickable
 import androidx.compose.foundation.layout.FlowRow
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.size
@@ -922,7 +922,7 @@ private fun ContributorRow(
             Column(
                 horizontalAlignment = Alignment.CenterHorizontally,
                 modifier =
-                    Modifier.combinedClickable(
+                    Modifier.contextClickable(
                             onClick = { if (hasProfile) onClick(person) },
                             onLongClick = {
                                 haptics.performHapticFeedback(HapticFeedbackType.LongPress)

manager/src/main/kotlin/org/matrix/vector/manager/ui/screens/modules/ScopeScreen.kt

@@ -43,7 +43,7 @@ import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.basicMarquee
 import androidx.compose.foundation.border
-import androidx.compose.foundation.combinedClickable
+import org.matrix.vector.ui.contextClickable
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.rounded.ArrowBack
@@ -960,7 +960,7 @@ private fun AppRow(
 
     ListItem(
         modifier =
-            Modifier.combinedClickable(
+            Modifier.contextClickable(
                     onClick = { if (enabled) onToggle(!app.isSelectedInScope) },
                     onLongClick = {
                         // The long press is where re-optimize lives, and re-optimize is the fix