Create image cache for use by json canvas

tools/skiaserve/skiaserve.cpp

Index: tools/skiaserve/skiaserve.cpp
diff --git a/tools/skiaserve/skiaserve.cpp b/tools/skiaserve/skiaserve.cpp
index 85e9c87c17b490eb32c1522152be9d30fcf8d368..a8ddcdf488f9d812e925ff8c2d8334908456450e 100644
--- a/tools/skiaserve/skiaserve.cpp
+++ b/tools/skiaserve/skiaserve.cpp
@@ -18,6 +18,8 @@
 #include "SkStream.h"
 #include "SkSurface.h"
 
+#include "UrlDataManager.h"
+
 #include <sys/socket.h>
 #include <microhttpd.h>
 
@@ -63,10 +65,11 @@ struct UploadContext {
 };
 
 struct Request {
-    Request() : fUploadContext(nullptr) {}
+    Request(SkString rootUrl) : fUploadContext(nullptr), fUrlDataManager(rootUrl) {}
     UploadContext* fUploadContext;
     SkAutoTUnref<SkPicture> fPicture;
     SkAutoTUnref<SkDebugCanvas> fDebugCanvas;
+    UrlDataManager fUrlDataManager;
 };
 
 // TODO factor this out into functions, also handle CPU path
@@ -99,6 +102,7 @@ SkData* writeCanvasToPng(SkCanvas* canvas) {
     }
 
     // write to png
+    // TODO encoding to png can be quite slow, we should investigate bmp
     SkData* png = SkImageEncoder::EncodeData(bmp, SkImageEncoder::kPNG_Type, 100);
     if (!png) {
         fprintf(stderr, "Can't encode to png\n");
@@ -411,6 +415,33 @@ public:
     }
 };
 
+class DataHandler : public UrlHandler {
+public:
+    bool canHandle(const char* method, const char* url) override {
+        static const char* kBaseUrl = "/data";
+        return 0 == strcmp(method, MHD_HTTP_METHOD_GET) &&
+               0 == strncmp(url, kBaseUrl, strlen(kBaseUrl));
+    }
+
+    int handle(Request* request, MHD_Connection* connection,
+               const char* url, const char* method,
+               const char* upload_data, size_t* upload_data_size) override {
+        SkTArray<SkString> commands;
+        SkStrSplit(url, "/", &commands);
+
+        if (!request->fPicture.get() || commands.count() != 2) {
+            return MHD_NO;
+        }
+
+        SkAutoTUnref<UrlDataManager::UrlData> urlData(
+            SkRef(request->fUrlDataManager.getDataFromUrl(SkString(url))));
+
+        if (urlData) {
+            return SendData(connection, urlData->fData.get(), urlData->fContentType.c_str());
+        }
+        return MHD_NO;
+    }
+};
 
 class RootHandler : public UrlHandler {
 public:
@@ -436,6 +467,7 @@ public:
         fHandlers.push_back(new CmdHandler);
         fHandlers.push_back(new InfoHandler);
         fHandlers.push_back(new DownloadHandler);
+        fHandlers.push_back(new DataHandler);
     }
 
     ~UrlManager() {
@@ -476,7 +508,7 @@ int answer_to_connection(void* cls, struct MHD_Connection* connection,
 }
 
 int skiaserve_main() {
-    Request request; // This simple server has one request
+    Request request(SkString("/data")); // This simple server has one request
     struct MHD_Daemon* daemon;
     // TODO Add option to bind this strictly to an address, e.g. localhost, for security.
     daemon = MHD_start_daemon(MHD_USE_SELECT_INTERNALLY, FLAGS_port, nullptr, nullptr,