[7.1.0] Avoid using InputStream.available() to detect EOF while rea…

…ding delimited protos. (#21143)

It's not a reliable method to check for EOF: it returns how many bytes
are guaranteed to be read without blocking, and the base implementation
always returns 0.

Instead, leverage the fact that parseDelimitedFrom() returns null if the
stream is at EOF.

PiperOrigin-RevId: 602257598
Change-Id: I61e51774611196fb44745dc0aa2dc836b41fcd68

src/main/java/com/google/devtools/build/lib/exec/ExpandedSpawnLogContext.java

@@ -268,8 +268,8 @@ public void close() throws IOException {
       if (sorted) {
         StableSort.stableSort(in, convertedOutputStream);
       } else {
-        while (in.available() > 0) {
-          SpawnExec ex = SpawnExec.parseDelimitedFrom(in);
+        SpawnExec ex;
+        while ((ex = SpawnExec.parseDelimitedFrom(in)) != null) {
           convertedOutputStream.write(ex);
         }
       }

src/main/java/com/google/devtools/build/lib/exec/StableSort.java

@@ -37,8 +37,8 @@
 public final class StableSort {
   private static ImmutableList<SpawnExec> read(InputStream in) throws IOException {
     ImmutableList.Builder<SpawnExec> result = ImmutableList.builder();
-    while (in.available() > 0) {
-      SpawnExec ex = SpawnExec.parseDelimitedFrom(in);
+    SpawnExec ex;
+    while ((ex = SpawnExec.parseDelimitedFrom(in)) != null) {
       result.add(ex);
     }
     return result.build();

src/test/java/com/google/devtools/build/lib/buildeventservice/BazelBuildEventServiceModuleTest.java

@@ -730,8 +730,9 @@ public void testCoverageFileIncluded() throws Exception {
 
     List<BuildEvent> buildEvents = new ArrayList<>();
     try (InputStream in = new FileInputStream(buildEventBinaryFile)) {
-      while (in.available() > 0) {
-        buildEvents.add(BuildEvent.parseDelimitedFrom(in));
+      BuildEvent ev;
+      while ((ev = BuildEvent.parseDelimitedFrom(in)) != null) {
+        buildEvents.add(ev);
       }
     }
 
@@ -842,8 +843,9 @@ private void testOom(Runnable throwOom) throws Exception {
 
     List<BuildEvent> buildEvents = new ArrayList<>();
     try (InputStream in = new FileInputStream(buildEventBinaryFile)) {
-      while (in.available() > 0) {
-        buildEvents.add(BuildEvent.parseDelimitedFrom(in));
+      BuildEvent ev;
+      while ((ev = BuildEvent.parseDelimitedFrom(in)) != null) {
+        buildEvents.add(ev);
       }
     }
     Aborted expectedAbort =

src/test/java/com/google/devtools/build/lib/buildtool/TargetCompleteEventTest.java

@@ -269,8 +269,9 @@ private static ImmutableList<BuildEvent> parseBuildEventsFromBEPStream(File bep)
       throws IOException {
     ImmutableList.Builder<BuildEvent> buildEvents = ImmutableList.builder();
     try (InputStream in = new FileInputStream(bep)) {
-      while (in.available() > 0) {
-        buildEvents.add(BuildEvent.parseDelimitedFrom(in));
+      BuildEvent ev;
+      while ((ev = BuildEvent.parseDelimitedFrom(in)) != null) {
+        buildEvents.add(ev);
       }
     }
     return buildEvents.build();

src/test/java/com/google/devtools/build/lib/exec/CompactSpawnLogContextTest.java

@@ -131,8 +131,8 @@ protected void closeAndAssertLog(SpawnLogContext context, SpawnExec... expected)
 
     ArrayList<SpawnExec> actual = new ArrayList<>();
     try (InputStream in = new ZstdInputStream(logPath.getInputStream())) {
-      while (in.available() > 0) {
-        ExecLogEntry e = ExecLogEntry.parseDelimitedFrom(in);
+      ExecLogEntry e;
+      while ((e = ExecLogEntry.parseDelimitedFrom(in)) != null) {
         entryMap.put(e.getId(), e);
         if (e.hasSpawn()) {
           actual.add(reconstructSpawnExec(e.getSpawn(), entryMap));

src/test/java/com/google/devtools/build/lib/exec/ExpandedSpawnLogContextTest.java

@@ -59,8 +59,8 @@ protected void closeAndAssertLog(SpawnLogContext context, SpawnExec... expected)
 
     ArrayList<SpawnExec> actual = new ArrayList<>();
     try (InputStream in = logPath.getInputStream()) {
-      while (in.available() > 0) {
-        SpawnExec ex = SpawnExec.parseDelimitedFrom(in);
+      SpawnExec ex;
+      while ((ex = SpawnExec.parseDelimitedFrom(in)) != null) {
         actual.add(ex);
       }
     }

src/tools/execlog/src/main/java/com/google/devtools/build/execlog/ExecLogParser.java

@@ -59,14 +59,12 @@ static class FilteringLogParser implements Parser {
     public SpawnExec getNext() throws IOException {
       SpawnExec ex;
       // Find the next record whose runner matches
-      do {
-        if (in.available() <= 0) {
-          // End of file
-          return null;
+      while ((ex = SpawnExec.parseDelimitedFrom(in)) != null) {
+        if (restrictToRunner == null || restrictToRunner.equals(ex.getRunner())) {
+          return ex;
         }
-        ex = SpawnExec.parseDelimitedFrom(in);
-      } while (restrictToRunner != null && !restrictToRunner.equals(ex.getRunner()));
-      return ex;
+      }
+      return null;
     }
   }