add command line flags

experimental/skpdiff/main.cpp

Index: experimental/skpdiff/main.cpp
diff --git a/experimental/skpdiff/main.cpp b/experimental/skpdiff/main.cpp
index 21bf7169d4dfa607bf627724612bb4cc9f85c675..81b1d633341deb13f9486caea592b299268d21a2 100644
--- a/experimental/skpdiff/main.cpp
+++ b/experimental/skpdiff/main.cpp
@@ -9,8 +9,9 @@
 #define __NO_STD_STRING // Uses cl::STRING_CLASS instead of std::string
 #include <CL/cl.hpp>
 
+#include "SkCommandLineFlags.h"
+#include "SkGraphics.h"
 #include "SkOSFile.h"
-#include "SkStream.h"
 #include "SkString.h"
 #include "SkTArray.h"
 #include "SkTDArray.h"
@@ -19,6 +20,15 @@
 #include "SkCLImageDiffer.h"
 #include "skpdiff_util.h"
 
+#include "SkForceLinking.h"
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
+// Command line argument definitions go here
+DEFINE_bool2(list, l, false, "List out available differs");
+DEFINE_string2(differs, d, "", "The names of the differs to use or all of them by default");
+DEFINE_string2(folders, f, "", "Compare two folders with identical subfile names: <baseline folder> <test folder>");
+DEFINE_string2(patterns, p, "", "Use two patterns to compare images: <baseline> <test>");
+
 /// A callback for any OpenCL errors
 CL_CALLBACK void error_notify(const char* errorInfo, const void* privateInfoSize, ::size_t cb, void* userData) {
     SkDebugf("OpenCL error notify: %s\n", errorInfo);
@@ -92,36 +102,149 @@ static void diff_directories(const char baselinePath[], const char testPath[], S
     }
 }
 
-static void print_help()
-{
-    SkDebugf(
-    "Usage:\n" \
-    "skpdiff <baseline directory> <test directory>\n\n"
-    );
-}
 
-int main(int argc, char** argv) {
-    if (argc != 3)
-    {
-        print_help();
-        return 1;
+/// Compares two sets of images identified by glob style patterns with the given differ
+static void diff_patterns(const char baselinePattern[], const char testPattern[], SkImageDiffer* differ) {
+    // Get the files in the baseline and test patterns. Because they are in sorted order, it's easy
+    // to find corresponding images by matching entry indices.
+    //
+    SkTArray<SkString> baselineEntries;
+    if (!glob_files(baselinePattern, &baselineEntries)) {
+        SkDebugf("Unable to get pattern \"%s\"\n", baselinePattern);
+        return;
     }
 
+    SkTArray<SkString> testEntries;
+    if (!glob_files(testPattern, &testEntries)) {
+        SkDebugf("Unable to get pattern \"%s\"\n", testPattern);
+        return;
+    }
+
+    if (baselineEntries.count() != testEntries.count()) {
+        SkDebugf("Baseline and test patterns do not yield corresponding number of files\n");
+        return;
+    }
+
+    SkTDArray<int> queuedDiffIDs;
+    for (int entryIndex = 0; entryIndex < baselineEntries.count(); entryIndex++) {
+        const char* baselineFilename = baselineEntries[entryIndex].c_str();
+        const char* testFilename     = testEntries    [entryIndex].c_str();
+        SkDebugf("%s %s\n", baselineFilename, testFilename);
+
+        int diffID = differ->queueDiffOfFile(baselineFilename, testFilename);
+        if (diffID >= 0) {
+            queuedDiffIDs.push(diffID);
+            SkDebugf("Result: %f\n", differ->getResult(diffID));
+        }
+    }
+}
+
+
+static bool init_cl_diff(SkImageDiffer* differ)
+{
     // Setup OpenCL
     cl::Device device;
     cl::Context context;
     if (!init_device_and_context(&device, &context)) {
-        return 1;
+        return false;
     }
 
     // Setup our differ of choice
-    SkCLImageDiffer* differ = SkNEW(SkDifferentPixelsImageDiffer);
-    if (!differ->init(device(), context())) {
-        return 1;
+    SkCLImageDiffer* clDiffer = (SkCLImageDiffer*)differ;
+    return clDiffer->init(device(), context());
+}
+
+// TODO Find a better home for the diff registry. One possibility is to have the differs self
+// register.
+
+// List here every differ
+SkDifferentPixelsImageDiffer gDiffPixel;
+
+/// A null terminated array of pointer to every differ declared above
+SkImageDiffer* gDiffers[] = { &gDiffPixel, NULL };
+
+/// A parallel array of functions to initialize the above differs
+bool (*gDiffInits[])(SkImageDiffer*) = { init_cl_diff, NULL };
+
+
+int main(int argc, char** argv) {
+    // Setup command line parsing
+    SkCommandLineFlags::SetUsage("Compare images using various metrics.");
+    SkCommandLineFlags::Parse(argc, argv);
+
+    // Needed by various Skia components
+    SkAutoGraphics ag;
+
+    if (FLAGS_list) {
+        SkDebugf("Available Metrics:\n");
+    }
+
+    // Figure which differs the user chose, and optionally print them if the user requests it
+    SkTDArray<int> chosenDiffers;
+    for (int differIndex = 0; NULL != gDiffers[differIndex]; differIndex++) {
+        if (FLAGS_list) {
+            SkDebugf("    %s", gDiffers[differIndex]->getName());
+            SkDebugf("\n");
+        }
+
+        // Check if this differ was chosen by any of the flags
+        if (FLAGS_differs.isEmpty()) {
+            // If no differs were chosen, they all get added
+            chosenDiffers.push(differIndex);
+        } else {
+            for (int flagIndex = 0; flagIndex < FLAGS_differs.count(); flagIndex++) {
+                if (SkString(FLAGS_differs[flagIndex]).equals(gDiffers[differIndex]->getName())) {
+                    chosenDiffers.push(differIndex);
+                    break;
+                }
+            }
+        }
+    }
+
+    // Don't attempt to initialize the differ if we aren't going to use it
+    if (FLAGS_folders.isEmpty() && FLAGS_patterns.isEmpty()) {
+        return 0;
     }
 
-    // Diff our folders
-    diff_directories(argv[1], argv[2], differ);
+    // Validate command line flags
+    if (!FLAGS_folders.isEmpty()) {
+        if (2 != FLAGS_folders.count()) {
+            SkDebugf("Folders flag expects two arguments: <baseline folder> <test folder>\n");
+            return 1;
+        }
+    }
+
+    if (!FLAGS_patterns.isEmpty()) {
+        if (2 != FLAGS_patterns.count()) {
+            SkDebugf("Patterns flag expects two arguments: <baseline pattern> <test pattern>\n");
+            return 1;
+        }
+    }
+
+    // TODO Move the differ loop to after the bitmaps are decoded and/or uploaded to the OpenCL
+    // device. Those are often the slowest processes and should not be done more than once if it can
+    // be helped.
+
+    // Perform each requested diff
+    for (int differIndex = 0; differIndex < chosenDiffers.count(); differIndex++) {
+        // Get the chosen differ and say which one they chose
+        SkImageDiffer * differ = gDiffers[differIndex];
+        SkDebugf("Using differ \"%s\"\n", differ->getName());
+
+        // Initialize the differ using the global list of init functions that match the list of
+        // differs
+        gDiffInits[differIndex](differ);
+
+        // Perform a folder diff if one is requested
+        if (!FLAGS_folders.isEmpty()) {
+            diff_directories(FLAGS_folders[0], FLAGS_folders[1], differ);
+        }
+
+        // Perform a pattern diff if one is requested
+        if (!FLAGS_patterns.isEmpty()) {
+            diff_patterns(FLAGS_patterns[0], FLAGS_patterns[1], differ);
+        }
+    }
 
     return 0;
 }