Implement a new caching system to make repeated runs much much faster.

hash.c

@@ -0,0 +1,132 @@
+#include <git2/repository.h>
+#include <git2/types.h>
+#include <linux/limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <stdint.h>
+#include <errno.h>
+
+#include "hash.h"
+#include "helpers.h"
+
+#ifdef GITHASH
+static uint64_t
+murmur64(uint64_t k)
+{
+  k ^= k >> 33;
+  k *= 0xff51afd7ed558ccdLLU;
+  k ^= k >> 33;
+  k *= 0xc4ceb9fe1a85ec53LLU;
+  k ^= k >> 33;
+
+  return k;
+}
+
+uint64_t
+generate_hash(git_repository *repo)
+{
+  struct stat dir, index;
+  char path[PATH_MAX] = { 0 };
+
+  const char *gitpath = git_repository_path(repo);
+  if (strlen(gitpath) + strlen("/..") > PATH_MAX - 1) {
+    L("strlen: %s", strerror(errno));
+    return -1;
+  }
+
+  strcat(path, gitpath);
+  if (stat(path, &index) < 0) {
+    return -1;
+  }
+  strcat(path, "/..");
+  if (stat(path, &dir) < 0) {
+    return -1;
+  }
+  return murmur64(dir.st_mtim.tv_nsec ^ index.st_mtim.tv_nsec);
+}
+
+repohash
+*read_hash(git_repository *repo)
+{
+  FILE *f;
+  uint64_t data;
+  uint8_t changes;
+  repohash *hash = malloc(sizeof(repohash));
+  char path[PATH_MAX] = { 0 };
+
+  const char *gitpath = git_repository_path(repo);
+  if (strlen(gitpath) + strlen(XD_HASH_PATH) > PATH_MAX - 1) {
+    L("strlen: %s", strerror(errno));
+    return NULL;
+  }
+  strcat(path, gitpath);
+  strcat(path, XD_HASH_PATH);
+
+  f = fopen(path, "r");
+  if (!f) {
+    L("fopen: %s", strerror(errno));
+    return NULL;
+  }
+
+  if (fread(&data, sizeof(uint64_t), 1, f) != 1) {
+    L("fread: %s", strerror(errno));
+    return NULL;
+  }
+
+  if (fseek(f, sizeof(uint64_t), SEEK_SET) < 0) {
+    L("fseek: %s", strerror(errno));
+    return NULL;
+  }
+
+  if (fread(&changes, sizeof(uint8_t), 1, f) != 1) {
+    L("fread: %s", strerror(errno));
+    return NULL;
+  }
+  fclose(f);
+
+  hash->hash = data;
+  hash->changes = changes;
+  return hash;
+}
+
+int
+write_hash(git_repository *repo, repohash hash)
+{
+  FILE *f;
+  char path[PATH_MAX] = { 0 };
+
+  const char *gitpath = git_repository_path(repo);
+  if (strlen(gitpath) + strlen(XD_HASH_PATH) > PATH_MAX - 1) {
+    L("strlen: %s", strerror(errno));
+    return 1;
+  }
+  strcat(path, gitpath);
+  strcat(path, XD_HASH_PATH);
+
+  f = fopen(path, "wb");
+  if (!f) {
+    L("fopen: %s", strerror(errno));
+    return 1;
+  }
+
+  if (fwrite(&hash.hash, sizeof(uint64_t), 1, f) != 1) {
+    L("fwrite: %s", strerror(errno));
+    return 1;
+  }
+
+  if (fseek(f, sizeof(uint64_t), SEEK_SET) < 0) {
+    L("fseek: %s", strerror(errno));
+    return 1;
+  }
+
+  if (fwrite(&hash.changes, sizeof(uint8_t), 1, f) != 1) {
+    L("fwrite: %s", strerror(errno));
+    return 1;
+  }
+
+  fclose(f);
+  return 0;
+}
+#endif