Begin work on AsyncFileReader demo

examples/helpers/AsyncFileReader.h

@@ -0,0 +1,82 @@
+#include <map>
+#include <cstring>
+#include <fstream>
+#include <sstream>
+#include <iostream>
+
+/* This is just a very simple and inefficient demo of async responses,
+ * please do roll your own variant or use a database or Node.js's async
+ * features instead of this really bad demo */
+struct AsyncFileReader {
+private:
+    /* The cache we have in memory for this file */
+    std::string cache;
+    int cacheOffset = 0;
+
+    /* The pending async file read (yes we only support one pending read) */
+    std::function<void(std::string_view)> pendingReadCb;
+
+    int fileSize;
+    std::ifstream fin;
+    uWS::Loop *loop;
+
+public:
+    /* Construct a demo async. file reader for fileName */
+    AsyncFileReader(std::string fileName) {
+        fin.open(fileName, std::ios::binary);
+
+        // get fileSize
+        fin.seekg(0, fin.end);
+        fileSize = fin.tellg();
+
+        //std::cout << "File size is: " << fileSize << std::endl;
+
+        // cache up 1 mb!
+        cache.resize(1024 * 1024);
+
+        //std::cout << "Caching 1 MB at offset = " << 0 << std::endl;
+        fin.seekg(0, fin.beg);
+        fin.read(cache.data(), cache.length());
+        cacheOffset = 0;
+
+        // get loop for thread
+
+        loop = uWS::Loop::defaultLoop();
+    }
+
+    /* Returns any data already cached for this offset */
+    std::string_view peek(int offset) {
+        /* Did we hit the cache? */
+        if (offset >= cacheOffset && ((offset - cacheOffset) < cache.length())) {
+            /* Cache hit */
+            //std::cout << "Cache hit!" << std::endl;
+            return std::string_view(cache.data() + offset - cacheOffset, cache.length() - offset + cacheOffset);
+        } else {
+            /* Cache miss */
+            //std::cout << "Cache miss!" << std::endl;
+            return std::string_view(nullptr, 0);
+        }
+    }
+
+    /* Asynchronously request more data at offset */
+    void request(int offset, std::function<void(std::string_view)> cb) {
+
+        // std::async this
+        //std::cout << "Caching 1 MB at offset = " << offset << std::endl;
+        fin.seekg(offset, fin.beg);
+        fin.read(cache.data(), cache.length());
+        cacheOffset = offset;
+
+        // Loop.defer this
+        cb(std::string_view(cache.data(), cache.length()));
+    }
+
+    /* Abort any pending async. request */
+    void abort() {
+
+    }
+
+    int getFileSize() {
+        return fileSize;
+    }
+};

examples/helpers/FileCache.h

@@ -1,49 +0,0 @@
-#include <experimental/filesystem>
-#include <map>
-#include <fstream>
-
-struct FileCache {
-private:
-    std::map<std::string_view, std::string_view> cache;
-
-    void cacheFile(std::string file, std::string root) {
-        std::cout << "Caching file: " << file << std::endl;
-
-        std::ifstream fin(root + file, std::ios::binary);
-        std::ostringstream oss;
-        oss << fin.rdbuf();
-
-        if (file == "/index.html") {
-            file = "/";
-        }
-
-        char *cachedFile = (char *) malloc(oss.str().size());
-        memcpy(cachedFile, oss.str().data(), oss.str().size());
-
-        char *key = (char *) malloc(file.length());
-        memcpy(key, file.data(), file.length());
-
-        std::cout << "Size: " << oss.str().size() << std::endl;
-
-        cache[std::string_view(key, file.length())] = std::string_view(cachedFile, oss.str().size());
-    }
-
-public:
-    FileCache(std::string root) {
-        for(auto &p : std::experimental::filesystem::recursive_directory_iterator(root)) {
-            cacheFile(p.path().string().substr(root.length()), root);
-        }
-    }
-
-    std::string_view getFile(std::string_view file) {
-        auto it = cache.find(file);
-
-        if (it == cache.end()) {
-//std::cout << "Did not find file: " << file << std::endl;
-            return "<h1>Nope!</h1>";
-        } else {
-//std::cout << "Did find file: " << file << std::endl;
-            return it->second;
-        }
-    }
-};