Add example that query github repositories

_example/mod_vtable/Makefile

@@ -0,0 +1,24 @@
+ifeq ($(OS),Windows_NT)
+EXE=extension.exe
+EXT=sqlite3_mod_vtable.dll
+RM=cmd /c del
+LIBCURL=-lcurldll
+LDFLAG=
+else
+EXE=extension
+EXT=sqlite3_mod_vtable.so
+RM=rm
+LDFLAG=-fPIC
+LIBCURL=-lcurl
+endif
+
+all : $(EXE) $(EXT)
+
+$(EXE) : extension.go
+	go build $<
+
+$(EXT) : sqlite3_mod_vtable.cc
+	g++ $(LDFLAG) -shared -o $@ $< -lsqlite3 $(LIBCURL)
+
+clean :
+	@-$(RM) $(EXE) $(EXT)

_example/mod_vtable/extension.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"github.com/mattn/go-sqlite3"
+	"log"
+)
+
+func main() {
+	sql.Register("sqlite3_with_extensions",
+		&sqlite3.SQLiteDriver{
+			Extensions: []string{
+				"sqlite3_mod_vtable",
+			},
+		})
+
+	db, err := sql.Open("sqlite3_with_extensions", ":memory:")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	db.Exec("create virtual table repo using github(id, full_name, description, html_url)")
+
+	rows, err := db.Query("select id, full_name, description, html_url from repo")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var id, full_name, description, html_url string
+		rows.Scan(&id, &full_name, &description, &html_url)
+		fmt.Printf("%s: %s\n\t%s\n\t%s\n\n", id, full_name, description, html_url)
+	}
+}

_example/mod_vtable/sqlite3_mod_vtable.cc

@@ -0,0 +1,238 @@
+#include <string>
+#include <sstream>
+#include <sqlite3.h>
+#include <sqlite3ext.h>
+#include <curl/curl.h>
+#include "picojson.h"
+
+#ifdef _WIN32
+# define EXPORT __declspec(dllexport)
+#else
+# define EXPORT
+#endif
+
+SQLITE_EXTENSION_INIT1;
+
+typedef struct {
+  char* data;   // response data from server
+  size_t size;  // response size of data
+} MEMFILE;
+
+MEMFILE*
+memfopen() {
+  MEMFILE* mf = (MEMFILE*) malloc(sizeof(MEMFILE));
+  if (mf) {
+    mf->data = NULL;
+    mf->size = 0;
+  }
+  return mf;
+}
+
+void
+memfclose(MEMFILE* mf) {
+  if (mf->data) free(mf->data);
+  free(mf);
+}
+
+size_t
+memfwrite(char* ptr, size_t size, size_t nmemb, void* stream) {
+  MEMFILE* mf = (MEMFILE*) stream;
+  int block = size * nmemb;
+  if (!mf) return block; // through
+  if (!mf->data)
+    mf->data = (char*) malloc(block);
+  else
+    mf->data = (char*) realloc(mf->data, mf->size + block);
+  if (mf->data) {
+    memcpy(mf->data + mf->size, ptr, block);
+    mf->size += block;
+  }
+  return block;
+}
+
+char*
+memfstrdup(MEMFILE* mf) {
+  char* buf;
+  if (mf->size == 0) return NULL;
+  buf = (char*) malloc(mf->size + 1);
+  memcpy(buf, mf->data, mf->size);
+  buf[mf->size] = 0;
+  return buf;
+}
+
+static int
+my_connect(sqlite3 *db, void *pAux, int argc, const char * const *argv, sqlite3_vtab **ppVTab, char **c) {
+  std::stringstream ss;
+  ss << "CREATE TABLE " << argv[0]
+    << "(id int, full_name text, description text, html_url text)";
+  int rc = sqlite3_declare_vtab(db, ss.str().c_str());
+  *ppVTab = (sqlite3_vtab *) sqlite3_malloc(sizeof(sqlite3_vtab));
+  memset(*ppVTab, 0, sizeof(sqlite3_vtab));
+  return rc;
+}
+
+static int
+my_create(sqlite3 *db, void *pAux, int argc, const char * const * argv, sqlite3_vtab **ppVTab, char **c) {
+  return my_connect(db, pAux, argc, argv, ppVTab, c);
+}
+
+static int my_disconnect(sqlite3_vtab *pVTab) {
+  sqlite3_free(pVTab);
+  return SQLITE_OK;
+}
+
+static int
+my_destroy(sqlite3_vtab *pVTab) {
+  sqlite3_free(pVTab);
+  return SQLITE_OK;
+}
+
+typedef struct {
+  sqlite3_vtab_cursor base;
+  int index;
+  picojson::value* rows;
+} cursor;
+
+static int
+my_open(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor) {
+  MEMFILE* mf;
+  CURL* curl;
+  char* json;
+  CURLcode res = CURLE_OK;
+  char error[CURL_ERROR_SIZE] = {0};
+  char* cert_file = getenv("SSL_CERT_FILE");
+
+  mf = memfopen();
+  curl = curl_easy_init();
+  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1);
+  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 2);
+  curl_easy_setopt(curl, CURLOPT_USERAGENT, "curl/7.29.0");
+  curl_easy_setopt(curl, CURLOPT_URL, "https://api.github.com/repositories");
+  if (cert_file)
+    curl_easy_setopt(curl, CURLOPT_CAINFO, cert_file);
+  curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
+  curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, error);
+  curl_easy_setopt(curl, CURLOPT_WRITEDATA, mf);
+  curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, memfwrite);
+  res = curl_easy_perform(curl);
+  curl_easy_cleanup(curl);
+  if (res != CURLE_OK) {
+    std::cerr << error << std::endl;
+    return SQLITE_FAIL;
+  }
+
+  picojson::value* v = new picojson::value;
+  std::string err;
+  picojson::parse(*v, mf->data, mf->data + mf->size, &err);
+  memfclose(mf);
+
+  if (!err.empty()) {
+    delete v;
+    std::cerr << err << std::endl;
+    return SQLITE_FAIL;
+  }
+
+  cursor *c = (cursor *)sqlite3_malloc(sizeof(cursor));
+  c->rows = v;
+  c->index = 0;
+  *ppCursor = &c->base;
+  return SQLITE_OK;
+}
+
+static int
+my_close(cursor *c) {
+  delete c->rows;
+  sqlite3_free(c);
+  return SQLITE_OK;
+}
+
+static int
+my_filter(cursor *c, int idxNum, const char *idxStr, int argc, sqlite3_value **argv) {
+  c->index = 0;
+  return SQLITE_OK;
+}
+
+static int
+my_next(cursor *c) {
+  c->index++;
+  return SQLITE_OK;
+}
+
+static int
+my_eof(cursor *c) {
+  return c->index >= c->rows->get<picojson::array>().size() ? 1 : 0;
+}
+
+static int
+my_column(cursor *c, sqlite3_context *ctxt, int i) {
+  picojson::value v = c->rows->get<picojson::array>()[c->index];
+  picojson::object row = v.get<picojson::object>();
+  const char* p = NULL;
+  switch (i) {
+  case 0:
+    p = row["id"].to_str().c_str();
+    break;
+  case 1:
+    p = row["full_name"].to_str().c_str();
+    break;
+  case 2:
+    p = row["description"].to_str().c_str();
+    break;
+  case 3:
+    p = row["html_url"].to_str().c_str();
+    break;
+  }
+  sqlite3_result_text(ctxt, strdup(p), strlen(p), free);
+  return SQLITE_OK;
+}
+
+static int
+my_rowid(cursor *c, sqlite3_int64 *pRowid) {
+  *pRowid = c->index;
+  return SQLITE_OK;
+}
+
+static int
+my_bestindex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo) {
+  return SQLITE_OK;
+}
+
+static const sqlite3_module module = {
+  0,
+  my_create,
+  my_connect,
+  my_bestindex,
+  my_disconnect,
+  my_destroy,
+  my_open,
+  (int (*)(sqlite3_vtab_cursor *)) my_close,
+  (int (*)(sqlite3_vtab_cursor *, int, char const *, int, sqlite3_value **)) my_filter,
+  (int (*)(sqlite3_vtab_cursor *)) my_next,
+  (int (*)(sqlite3_vtab_cursor *)) my_eof,
+  (int (*)(sqlite3_vtab_cursor *, sqlite3_context *, int)) my_column,
+  (int (*)(sqlite3_vtab_cursor *, sqlite3_int64 *)) my_rowid,
+  NULL, // my_update
+  NULL, // my_begin
+  NULL, // my_sync
+  NULL, // my_commit
+  NULL, // my_rollback
+  NULL, // my_findfunction
+  NULL, // my_rename
+};
+
+static void
+destructor(void *arg) {
+  return;
+}
+
+
+extern "C" {
+
+EXPORT int
+sqlite3_extension_init(sqlite3 *db, char **errmsg, const sqlite3_api_routines *api) {
+  SQLITE_EXTENSION_INIT2(api);
+  sqlite3_create_module_v2(db, "github", &module, NULL, destructor);
+  return 0;
+}
+
+}