Add new skpinfo tool

tools/skpinfo.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkCommandLineFlags.h"
+#include "SkPicture.h"
+#include "SkPicturePlayback.h"
+#include "SkStream.h"
+
+DEFINE_string2(input, i, "", "skp on which to report");
+DEFINE_bool2(version, v, true, "version");
+DEFINE_bool2(width, w, true, "width");
+DEFINE_bool2(height, h, true, "height");
+DEFINE_bool2(tags, t, true, "tags");
+DEFINE_bool2(quiet, q, false, "quiet");
+
+// This tool can print simple information about an SKP but its main use
+// is just to check if an SKP has been truncated during the recording

[mtklein, 2014/03/03 15:48:48]

Just curious: do you suspect they're truncated during recording, or truncated
while writing to disk?  Like, did we just forget an fflush somewhere, or do we
have a recording bug?

[robertphillips, 2014/03/03 16:13:18]

I suspect they are being truncated during writing. No idea why though.

+// process.
+// return codes:
+static const int kSuccess = 0;
+static const int kTruncatedFile = 1;
+static const int kNotAnSKP = 2;
+static const int kInvalidTag = 3;
+static const int kMissingInput = 4;
+
+int tool_main(int argc, char** argv);
+int tool_main(int argc, char** argv) {
+    SkCommandLineFlags::SetUsage("Prints information about an skp file");
+    SkCommandLineFlags::Parse(argc, argv);
+
+    if (FLAGS_input.count() != 1) {
+        return kMissingInput;

[mtklein, 2014/03/03 15:48:48]

Seems like it'd be nice to SkDebugf some message on errors when !FLAGS_quiet?

[robertphillips, 2014/03/03 16:13:18]

Done.

+    }
+
+    const char* fileName = FLAGS_input[0];
+
+    SkStream* stream = SkNEW_ARGS(SkFILEStream, (fileName));

[mtklein, 2014/03/03 15:48:48]

SkFILEStream stream(FLAGS_input[0]); ?

Might also want to check stream isValid() after creating it.

[robertphillips, 2014/03/03 16:13:18]

Done. Somewhat surprised isValid isn't virtual.

+
+    size_t len = stream->getLength();
+
+    SkPictInfo info;
+    if (!SkPicture::StreamIsSKP(stream, &info)) {
+        return kNotAnSKP;
+    }
+
+    if (FLAGS_version && !FLAGS_quiet) {
+        SkDebugf("Version: %d\n", info.fVersion);
+    }
+    if (FLAGS_width && !FLAGS_quiet) {
+        SkDebugf("Width: %d\n", info.fWidth);
+    }
+    if (FLAGS_height && !FLAGS_quiet) {
+        SkDebugf("Height: %d\n", info.fHeight);
+    }
+
+    if (!stream->readBool()) {

[mtklein, 2014/03/03 15:48:48]

Got confused here.  Clearer as this?

if (stream->isAtEnd()) {
  return kSuccess;
}

[robertphillips, 2014/03/03 16:13:18]

Here we're getting into the oddities of the picture format. It stores a bool to
determine if there is a playback object in the file. If it doesn't then we're
done reading the file.

I've added a comment.

+        return kSuccess;
+    }
+
+    for (;;) {
+        uint32_t tag = stream->readU32();
+        if (SK_PICT_EOF_TAG == tag) {
+            break;
+        }
+
+        uint32_t size = stream->readU32();

[mtklein, 2014/03/03 15:48:48]

tableSize?  I'm sometimes getting a bit tripped up by size/len.

[robertphillips, 2014/03/03 16:13:18]

Done. I renamed these to chunkSize & totStreamSize

+        size_t curPos = stream->getPosition();
+
+        // "move" doesn't error out when seeking beyond the end of file
+        // so we need a preemptive check here.
+        if (curPos+size > len) {
+            if (!FLAGS_quiet) {
+                SkDebugf("truncated file\n");
+            }
+            return kTruncatedFile;
+        }
+
+        switch (tag) {
+        case SK_PICT_READER_TAG: 
+            if (FLAGS_tags && !FLAGS_quiet) {
+                SkDebugf("SK_PICT_READER_TAG %d\n", size);
+            }
+            break;
+        case SK_PICT_FACTORY_TAG:
+            if (FLAGS_tags && !FLAGS_quiet) {
+                SkDebugf("SK_PICT_FACTORY_TAG %d\n", size);
+                SkDebugf("Exiting early due to format limitations\n");

[mtklein, 2014/03/03 15:48:48]

What's the deal with these early exits and TODOs?

[robertphillips, 2014/03/03 16:13:18]

The size stored with each tag isn't always the size of the chunk in bytes. For
the three early exit cases it is something like "the number of fonts". I would
like to change the format so the size associated with each tag is the number of
bytes and then the tag-specific size is stored within that chunk. For the
current use case this early out seems to be sufficient (since the truncation has
already happened in the PICT_READER_TAG).

[mtklein, 2014/03/03 16:27:37]

Ah!  Right.  I even knew this.  Thanks for the reminder.  Can you add this to
the code as a comment?

[robertphillips, 2014/03/03 18:44:24]

Done.

+            }
+            return kSuccess;       // TODO: need to store size in bytes
+            break;
+        case SK_PICT_TYPEFACE_TAG:
+            if (FLAGS_tags && !FLAGS_quiet) {
+                SkDebugf("SK_PICT_TYPEFACE_TAG %d\n", size);
+                SkDebugf("Exiting early due to format limitations\n");
+            }
+            return kSuccess;       // TODO: need to store size in bytes
+            break;
+        case SK_PICT_PICTURE_TAG:
+            if (FLAGS_tags && !FLAGS_quiet) {
+                SkDebugf("SK_PICT_PICTURE_TAG %d\n", size);
+                SkDebugf("Exiting early due to format limitations\n");
+            }
+            return kSuccess;       // TODO: need to store size in bytes
+            break;
+        case SK_PICT_BUFFER_SIZE_TAG:
+            if (FLAGS_tags && !FLAGS_quiet) {
+                SkDebugf("SK_PICT_BUFFER_SIZE_TAG %d\n", size);
+            }
+            break;
+        default:
+            if (!FLAGS_quiet) {
+                SkDebugf("Unknown tag %d\n", size);
+            }
+            return kInvalidTag;
+        }
+
+        if (!stream->move(size)) {
+            if (!FLAGS_quiet) {
+                SkDebugf("seek error\n");
+            }
+            return kTruncatedFile;
+        }
+    }
+
+    return kSuccess;
+}
+
+#if !defined SK_BUILD_FOR_IOS
+int main(int argc, char * const argv[]) {

[mtklein, 2014/03/03 15:48:48]

I'm always puzzled why we don't just write int main(int argc, char** argv)

[robertphillips, 2014/03/03 16:13:18]

I think iOS will reject that.

[mtklein, 2014/03/03 16:27:37]

This code is ifdef'd out on iOS?  Anyway, not important.

+    return tool_main(argc, (char**) argv);
+}
+#endif