add basic request caching with sqlite

1 files changed, 141 insertions, 2 deletions

diff --git a/src/util/filesource.cpp b/src/util/filesource.cpp
index 503d4dfb1d..3f52a09119 100644
--- a/src/util/filesource.cpp
+++ b/src/util/filesource.cpp
@@ -1,13 +1,46 @@
 #include <mbgl/util/filesource.hpp>
 #include <mbgl/platform/platform.hpp>
+#include <mbgl/platform/log.hpp>
+
+#include <sqlite3.h>
 
 #include <fstream>
 #include <sstream>
 
 namespace mbgl {
 
-FileSource::FileSource() {}
+FileSource::FileSource() {
+    const int err = sqlite3_open_v2("cache.db", &db, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, nullptr);
+    if (err != SQLITE_OK) {
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        db = nullptr;
+    }
+
+    createSchema();
+}
+
+FileSource::~FileSource() {
+    closeDatabase();
+}
+
+void FileSource::createSchema() {
+    if (db) {
+        // Create schema
+        const int err = sqlite3_exec(db, "CREATE TABLE IF NOT EXISTS `http_cache` (`url` TEXT PRIMARY KEY, `expires` INTEGER, `data` BLOB)", nullptr, nullptr, nullptr);
+        if (err != SQLITE_OK) {
+            Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+            closeDatabase();
+        }
+    }
+}
 
+void FileSource::closeDatabase() {
+    if (db) {
+        const int err = sqlite3_close_v2(db);
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        db = nullptr;
+    }
+}
 
 void FileSource::setBase(const std::string &value) {
     base = value;
@@ -17,6 +50,104 @@ const std::string &FileSource::getBase() const {
     return base;
 }
 
+bool FileSource::loadFile(const std::string &url, std::function<void(platform::Response *)> callback) {
+    if (!db) {
+        return false;
+    }
+
+    sqlite3_stmt *stmt = nullptr;
+    int err;
+
+    err = sqlite3_prepare_v2(db, "SELECT `data` FROM `http_cache` WHERE `url` = ?", -1, &stmt, nullptr);
+    if (err != SQLITE_OK) {
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        return false;
+    }
+
+    err = sqlite3_bind_text(stmt, 1, url.data(), url.size(), nullptr);
+    if (err != SQLITE_OK) {
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        err = sqlite3_finalize(stmt);
+        if (err != SQLITE_OK) {
+            Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        }
+        return false;
+    }
+
+    bool status = false;
+
+    err = sqlite3_step(stmt);
+    if (err == SQLITE_ROW) {
+        // There is data.
+        platform::Response res(callback);
+        res.code = 200;
+        const char *data = reinterpret_cast<const char *>(sqlite3_column_blob(stmt, 0));
+        const size_t size = sqlite3_column_bytes(stmt, 0);
+        res.body = { data, size };
+        callback(&res);
+        status = true;
+    } else if (err == SQLITE_DONE) {
+        // There is no data.
+        // This is a noop.
+    } else {
+        // Another error occured.
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+    }
+
+    err = sqlite3_finalize(stmt);
+    if (err != SQLITE_OK) {
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+    }
+    return status;
+}
+
+void FileSource::saveFile(const std::string &url, platform::Response *const res) {
+    if (!db) {
+        return;
+    }
+
+    sqlite3_stmt *stmt = nullptr;
+    int err;
+
+    err = sqlite3_prepare_v2(db, "REPLACE INTO `http_cache` (`url`, `data`) VALUES(?, ?)", -1, &stmt, nullptr);
+    if (err != SQLITE_OK) {
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        return;
+    }
+
+    err = sqlite3_bind_text(stmt, 1, url.data(), url.size(), nullptr);
+    if (err != SQLITE_OK) {
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        err = sqlite3_finalize(stmt);
+        if (err != SQLITE_OK) {
+            Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        }
+        return;
+    }
+
+    err = sqlite3_bind_blob(stmt, 2, res->body.data(), res->body.size(), nullptr);
+    if (err != SQLITE_OK) {
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        err = sqlite3_finalize(stmt);
+        if (err != SQLITE_OK) {
+            Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+        }
+        return;
+    }
+
+    err = sqlite3_step(stmt);
+    if (err != SQLITE_DONE) {
+        // Another error occured.
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+    }
+
+    err = sqlite3_finalize(stmt);
+    if (err != SQLITE_OK) {
+        Log::Warning(Event::Database, "%s: %s", sqlite3_errstr(err), sqlite3_errmsg(db));
+    }
+}
+
+
 void FileSource::load(ResourceType /*type*/, const std::string &url, std::function<void(platform::Response *)> callback, const std::shared_ptr<uv::loop> loop) {
     // convert relative URLs to absolute URLs
 
@@ -51,7 +182,15 @@ void FileSource::load(ResourceType /*type*/, const std::string &url, std::functi
         callback(&response);
     } else {
         // load from the internet
-        platform::request_http(absoluteURL, callback, loop);
+        if (!loadFile(absoluteURL, callback)) {
+            const std::shared_ptr<FileSource> source = shared_from_this();
+            platform::request_http(absoluteURL, [=](platform::Response *res) {
+                if (res->code == 200) {
+                    source->saveFile(absoluteURL, res);
+                }
+                callback(res);
+            }, loop);
+        }
     }
 }