Godeps, vendor: convert dependency management to trash (#3198)

This commit converts the dependency management from Godeps to the vendor
folder, also switching the tool from godep to trash. Since the upstream tool
lacks a few features proposed via a few PRs, until those PRs are merged in
(if), use github.com/karalabe/trash.

You can update dependencies via trash --update.

All dependencies have been updated to their latest version.

Parts of the build system are reworked to drop old notions of Godeps and
invocation of the go vet command so that it doesn't run against the vendor
folder, as that will just blow up during vetting.

The conversion drops OpenCL (and hence GPU mining support) from ethash and our
codebase. The short reasoning is that there's noone to maintain and having
opencl libs in our deps messes up builds as go install ./... tries to build
them, failing with unsatisfied link errors for the C OpenCL deps.

golang.org/x/net/context is not vendored in. We expect it to be fetched by the
user (i.e. using go get). To keep ci.go builds reproducible the package is
"vendored" in build/_vendor.

1 files changed, 119 insertions, 0 deletions

diff --git a/vendor/github.com/ethereum/ethash/src/libethash/io.c b/vendor/github.com/ethereum/ethash/src/libethash/io.c
new file mode 100644
index 000000000..f4db477c2
--- /dev/null
+++ b/vendor/github.com/ethereum/ethash/src/libethash/io.c
@@ -0,0 +1,119 @@
+/*
+  This file is part of ethash.
+
+  ethash is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  ethash is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with ethash.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/** @file io.c
+ * @author Lefteris Karapetsas <lefteris@ethdev.com>
+ * @date 2015
+ */
+#include "io.h"
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+enum ethash_io_rc ethash_io_prepare(
+	char const* dirname,
+	ethash_h256_t const seedhash,
+	FILE** output_file,
+	uint64_t file_size,
+	bool force_create
+)
+{
+	char mutable_name[DAG_MUTABLE_NAME_MAX_SIZE];
+	enum ethash_io_rc ret = ETHASH_IO_FAIL;
+	// reset errno before io calls
+	errno = 0;
+
+	// assert directory exists
+	if (!ethash_mkdir(dirname)) {
+		ETHASH_CRITICAL("Could not create the ethash directory");
+		goto end;
+	}
+
+	ethash_io_mutable_name(ETHASH_REVISION, &seedhash, mutable_name);
+	char* tmpfile = ethash_io_create_filename(dirname, mutable_name, strlen(mutable_name));
+	if (!tmpfile) {
+		ETHASH_CRITICAL("Could not create the full DAG pathname");
+		goto end;
+	}
+
+	FILE *f;
+	if (!force_create) {
+		// try to open the file
+		f = ethash_fopen(tmpfile, "rb+");
+		if (f) {
+			size_t found_size;
+			if (!ethash_file_size(f, &found_size)) {
+				fclose(f);
+				ETHASH_CRITICAL("Could not query size of DAG file: \"%s\"", tmpfile);
+				goto free_memo;
+			}
+			if (file_size != found_size - ETHASH_DAG_MAGIC_NUM_SIZE) {
+				fclose(f);
+				ret = ETHASH_IO_MEMO_SIZE_MISMATCH;
+				goto free_memo;
+			}
+			// compare the magic number, no need to care about endianess since it's local
+			uint64_t magic_num;
+			if (fread(&magic_num, ETHASH_DAG_MAGIC_NUM_SIZE, 1, f) != 1) {
+				// I/O error
+				fclose(f);
+				ETHASH_CRITICAL("Could not read from DAG file: \"%s\"", tmpfile);
+				ret = ETHASH_IO_MEMO_SIZE_MISMATCH;
+				goto free_memo;
+			}
+			if (magic_num != ETHASH_DAG_MAGIC_NUM) {
+				fclose(f);
+				ret = ETHASH_IO_MEMO_SIZE_MISMATCH;
+				goto free_memo;
+			}
+			ret = ETHASH_IO_MEMO_MATCH;
+			goto set_file;
+		}
+	}
+	
+	// file does not exist, will need to be created
+	f = ethash_fopen(tmpfile, "wb+");
+	if (!f) {
+		ETHASH_CRITICAL("Could not create DAG file: \"%s\"", tmpfile);
+		goto free_memo;
+	}
+	// make sure it's of the proper size
+	if (fseek(f, (long int)(file_size + ETHASH_DAG_MAGIC_NUM_SIZE - 1), SEEK_SET) != 0) {
+		fclose(f);
+		ETHASH_CRITICAL("Could not seek to the end of DAG file: \"%s\". Insufficient space?", tmpfile);
+		goto free_memo;
+	}
+	if (fputc('\n', f) == EOF) {
+		fclose(f);
+		ETHASH_CRITICAL("Could not write in the end of DAG file: \"%s\". Insufficient space?", tmpfile);
+		goto free_memo;
+	}
+	if (fflush(f) != 0) {
+		fclose(f);
+		ETHASH_CRITICAL("Could not flush at end of DAG file: \"%s\". Insufficient space?", tmpfile);
+		goto free_memo;
+	}
+	ret = ETHASH_IO_MEMO_MISMATCH;
+	goto set_file;
+
+	ret = ETHASH_IO_MEMO_MATCH;
+set_file:
+	*output_file = f;
+free_memo:
+	free(tmpfile);
+end:
+	return ret;
+}