diff --git a/common.h b/common.h
new file mode 100644
index 0000000000..c0fdc5eb98
--- /dev/null
+++ b/common.h
@@ -0,0 +1,475 @@
+#ifndef COMMON_H
+#define COMMON_H
+
+#include "git-compat-util.h"
+#include "wrapper.h"
+
+/*
+ * ARRAY_SIZE - get the number of elements in a visible array
+ * @x: the array whose size you want.
+ *
+ * This does not work on pointers, or arrays declared as [], or
+ * function parameters.  With correct compiler support, such usage
+ * will cause a build error (see the build_assert_or_zero macro).
+ */
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + BARF_UNLESS_AN_ARRAY(x))
+
+#define bitsizeof(x)  (CHAR_BIT * sizeof(x))
+
+#define maximum_signed_value_of_type(a) \
+    (INTMAX_MAX >> (bitsizeof(intmax_t) - bitsizeof(a)))
+
+#define maximum_unsigned_value_of_type(a) \
+    (UINTMAX_MAX >> (bitsizeof(uintmax_t) - bitsizeof(a)))
+
+/*
+ * Signed integer overflow is undefined in C, so here's a helper macro
+ * to detect if the sum of two integers will overflow.
+ *
+ * Requires: a >= 0, typeof(a) equals typeof(b)
+ */
+#define signed_add_overflows(a, b) \
+    ((b) > maximum_signed_value_of_type(a) - (a))
+
+#define unsigned_add_overflows(a, b) \
+    ((b) > maximum_unsigned_value_of_type(a) - (a))
+
+/*
+ * Returns true if the multiplication of "a" and "b" will
+ * overflow. The types of "a" and "b" must match and must be unsigned.
+ * Note that this macro evaluates "a" twice!
+ */
+#define unsigned_mult_overflows(a, b) \
+    ((a) && (b) > maximum_unsigned_value_of_type(a) / (a))
+
+/*
+ * Returns true if the left shift of "a" by "shift" bits will
+ * overflow. The type of "a" must be unsigned.
+ */
+#define unsigned_left_shift_overflows(a, shift) \
+    ((shift) < bitsizeof(a) && \
+     (a) > maximum_unsigned_value_of_type(a) >> (shift))
+
+#define MSB(x, bits) ((x) & TYPEOF(x)(~0ULL << (bitsizeof(x) - (bits))))
+#define HAS_MULTI_BITS(i)  ((i) & ((i) - 1))  /* checks if an integer has more than 1 bit set */
+
+#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
+
+/* Approximation of the length of the decimal representation of this type. */
+#define decimal_length(x)	((int)(sizeof(x) * 2.56 + 0.5) + 1)
+
+/*
+ * If the string "str" begins with the string found in "prefix", return 1.
+ * The "out" parameter is set to "str + strlen(prefix)" (i.e., to the point in
+ * the string right after the prefix).
+ *
+ * Otherwise, return 0 and leave "out" untouched.
+ *
+ * Examples:
+ *
+ *   [extract branch name, fail if not a branch]
+ *   if (!skip_prefix(ref, "refs/heads/", &branch)
+ *	return -1;
+ *
+ *   [skip prefix if present, otherwise use whole string]
+ *   skip_prefix(name, "refs/heads/", &name);
+ */
+static inline int skip_prefix(const char *str, const char *prefix,
+			      const char **out)
+{
+	do {
+		if (!*prefix) {
+			*out = str;
+			return 1;
+		}
+	} while (*str++ == *prefix++);
+	return 0;
+}
+
+/*
+ * Like skip_prefix, but promises never to read past "len" bytes of the input
+ * buffer, and returns the remaining number of bytes in "out" via "outlen".
+ */
+static inline int skip_prefix_mem(const char *buf, size_t len,
+				  const char *prefix,
+				  const char **out, size_t *outlen)
+{
+	size_t prefix_len = strlen(prefix);
+	if (prefix_len <= len && !memcmp(buf, prefix, prefix_len)) {
+		*out = buf + prefix_len;
+		*outlen = len - prefix_len;
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * If buf ends with suffix, return 1 and subtract the length of the suffix
+ * from *len. Otherwise, return 0 and leave *len untouched.
+ */
+static inline int strip_suffix_mem(const char *buf, size_t *len,
+				   const char *suffix)
+{
+	size_t suflen = strlen(suffix);
+	if (*len < suflen || memcmp(buf + (*len - suflen), suffix, suflen))
+		return 0;
+	*len -= suflen;
+	return 1;
+}
+
+/*
+ * If str ends with suffix, return 1 and set *len to the size of the string
+ * without the suffix. Otherwise, return 0 and set *len to the size of the
+ * string.
+ *
+ * Note that we do _not_ NUL-terminate str to the new length.
+ */
+static inline int strip_suffix(const char *str, const char *suffix, size_t *len)
+{
+	*len = strlen(str);
+	return strip_suffix_mem(str, len, suffix);
+}
+
+#define SWAP(a, b) do {						\
+	void *_swap_a_ptr = &(a);				\
+	void *_swap_b_ptr = &(b);				\
+	unsigned char _swap_buffer[sizeof(a)];			\
+	memcpy(_swap_buffer, _swap_a_ptr, sizeof(a));		\
+	memcpy(_swap_a_ptr, _swap_b_ptr, sizeof(a) +		\
+	       BUILD_ASSERT_OR_ZERO(sizeof(a) == sizeof(b)));	\
+	memcpy(_swap_b_ptr, _swap_buffer, sizeof(a));		\
+} while (0)
+
+static inline size_t st_add(size_t a, size_t b)
+{
+	if (unsigned_add_overflows(a, b))
+		die("size_t overflow: %"PRIuMAX" + %"PRIuMAX,
+		    (uintmax_t)a, (uintmax_t)b);
+	return a + b;
+}
+#define st_add3(a,b,c)   st_add(st_add((a),(b)),(c))
+#define st_add4(a,b,c,d) st_add(st_add3((a),(b),(c)),(d))
+
+static inline size_t st_mult(size_t a, size_t b)
+{
+	if (unsigned_mult_overflows(a, b))
+		die("size_t overflow: %"PRIuMAX" * %"PRIuMAX,
+		    (uintmax_t)a, (uintmax_t)b);
+	return a * b;
+}
+
+static inline size_t st_sub(size_t a, size_t b)
+{
+	if (a < b)
+		die("size_t underflow: %"PRIuMAX" - %"PRIuMAX,
+		    (uintmax_t)a, (uintmax_t)b);
+	return a - b;
+}
+
+static inline size_t st_left_shift(size_t a, unsigned shift)
+{
+	if (unsigned_left_shift_overflows(a, shift))
+		die("size_t overflow: %"PRIuMAX" << %u",
+		    (uintmax_t)a, shift);
+	return a << shift;
+}
+
+static inline unsigned long cast_size_t_to_ulong(size_t a)
+{
+	if (a != (unsigned long)a)
+		die("object too large to read on this platform: %"
+		    PRIuMAX" is cut off to %lu",
+		    (uintmax_t)a, (unsigned long)a);
+	return (unsigned long)a;
+}
+
+static inline int cast_size_t_to_int(size_t a)
+{
+	if (a > INT_MAX)
+		die("number too large to represent as int on this platform: %"PRIuMAX,
+		    (uintmax_t)a);
+	return (int)a;
+}
+
+
+/*
+ * FREE_AND_NULL(ptr) is like free(ptr) followed by ptr = NULL. Note
+ * that ptr is used twice, so don't pass e.g. ptr++.
+ */
+#define FREE_AND_NULL(p) do { free(p); (p) = NULL; } while (0)
+
+#define ALLOC_ARRAY(x, alloc) (x) = xmalloc(st_mult(sizeof(*(x)), (alloc)))
+#define CALLOC_ARRAY(x, alloc) (x) = xcalloc((alloc), sizeof(*(x)))
+#define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc)))
+
+#define COPY_ARRAY(dst, src, n) copy_array((dst), (src), (n), sizeof(*(dst)) + \
+	BARF_UNLESS_COPYABLE((dst), (src)))
+static inline void copy_array(void *dst, const void *src, size_t n, size_t size)
+{
+	if (n)
+		memcpy(dst, src, st_mult(size, n));
+}
+
+#define MOVE_ARRAY(dst, src, n) move_array((dst), (src), (n), sizeof(*(dst)) + \
+	BARF_UNLESS_COPYABLE((dst), (src)))
+static inline void move_array(void *dst, const void *src, size_t n, size_t size)
+{
+	if (n)
+		memmove(dst, src, st_mult(size, n));
+}
+
+#define DUP_ARRAY(dst, src, n) do { \
+	size_t dup_array_n_ = (n); \
+	COPY_ARRAY(ALLOC_ARRAY((dst), dup_array_n_), (src), dup_array_n_); \
+} while (0)
+
+/*
+ * These functions help you allocate structs with flex arrays, and copy
+ * the data directly into the array. For example, if you had:
+ *
+ *   struct foo {
+ *     int bar;
+ *     char name[FLEX_ARRAY];
+ *   };
+ *
+ * you can do:
+ *
+ *   struct foo *f;
+ *   FLEX_ALLOC_MEM(f, name, src, len);
+ *
+ * to allocate a "foo" with the contents of "src" in the "name" field.
+ * The resulting struct is automatically zero'd, and the flex-array field
+ * is NUL-terminated (whether the incoming src buffer was or not).
+ *
+ * The FLEXPTR_* variants operate on structs that don't use flex-arrays,
+ * but do want to store a pointer to some extra data in the same allocated
+ * block. For example, if you have:
+ *
+ *   struct foo {
+ *     char *name;
+ *     int bar;
+ *   };
+ *
+ * you can do:
+ *
+ *   struct foo *f;
+ *   FLEXPTR_ALLOC_STR(f, name, src);
+ *
+ * and "name" will point to a block of memory after the struct, which will be
+ * freed along with the struct (but the pointer can be repointed anywhere).
+ *
+ * The *_STR variants accept a string parameter rather than a ptr/len
+ * combination.
+ *
+ * Note that these macros will evaluate the first parameter multiple
+ * times, and it must be assignable as an lvalue.
+ */
+#define FLEX_ALLOC_MEM(x, flexname, buf, len) do { \
+	size_t flex_array_len_ = (len); \
+	(x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
+	memcpy((void *)(x)->flexname, (buf), flex_array_len_); \
+} while (0)
+#define FLEXPTR_ALLOC_MEM(x, ptrname, buf, len) do { \
+	size_t flex_array_len_ = (len); \
+	(x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
+	memcpy((x) + 1, (buf), flex_array_len_); \
+	(x)->ptrname = (void *)((x)+1); \
+} while(0)
+#define FLEX_ALLOC_STR(x, flexname, str) \
+	FLEX_ALLOC_MEM((x), flexname, (str), strlen(str))
+#define FLEXPTR_ALLOC_STR(x, ptrname, str) \
+	FLEXPTR_ALLOC_MEM((x), ptrname, (str), strlen(str))
+
+static inline char *xstrdup_or_null(const char *str)
+{
+	return str ? xstrdup(str) : NULL;
+}
+
+static inline size_t xsize_t(off_t len)
+{
+	if (len < 0 || (uintmax_t) len > SIZE_MAX)
+		die("Cannot handle files this big");
+	return (size_t) len;
+}
+
+/* in ctype.c, for kwset users */
+extern const unsigned char tolower_trans_tbl[256];
+
+/* Sane ctype - no locale, and works with signed chars */
+#undef isascii
+#undef isspace
+#undef isdigit
+#undef isalpha
+#undef isalnum
+#undef isprint
+#undef islower
+#undef isupper
+#undef tolower
+#undef toupper
+#undef iscntrl
+#undef ispunct
+#undef isxdigit
+
+extern const unsigned char sane_ctype[256];
+extern const signed char hexval_table[256];
+#define GIT_SPACE 0x01
+#define GIT_DIGIT 0x02
+#define GIT_ALPHA 0x04
+#define GIT_GLOB_SPECIAL 0x08
+#define GIT_REGEX_SPECIAL 0x10
+#define GIT_PATHSPEC_MAGIC 0x20
+#define GIT_CNTRL 0x40
+#define GIT_PUNCT 0x80
+#define sane_istest(x,mask) ((sane_ctype[(unsigned char)(x)] & (mask)) != 0)
+#define isascii(x) (((x) & ~0x7f) == 0)
+#define isspace(x) sane_istest(x,GIT_SPACE)
+#define isdigit(x) sane_istest(x,GIT_DIGIT)
+#define isalpha(x) sane_istest(x,GIT_ALPHA)
+#define isalnum(x) sane_istest(x,GIT_ALPHA | GIT_DIGIT)
+#define isprint(x) ((x) >= 0x20 && (x) <= 0x7e)
+#define islower(x) sane_iscase(x, 1)
+#define isupper(x) sane_iscase(x, 0)
+#define is_glob_special(x) sane_istest(x,GIT_GLOB_SPECIAL)
+#define is_regex_special(x) sane_istest(x,GIT_GLOB_SPECIAL | GIT_REGEX_SPECIAL)
+#define iscntrl(x) (sane_istest(x,GIT_CNTRL))
+#define ispunct(x) sane_istest(x, GIT_PUNCT | GIT_REGEX_SPECIAL | \
+		GIT_GLOB_SPECIAL | GIT_PATHSPEC_MAGIC)
+#define isxdigit(x) (hexval_table[(unsigned char)(x)] != -1)
+#define tolower(x) sane_case((unsigned char)(x), 0x20)
+#define toupper(x) sane_case((unsigned char)(x), 0)
+#define is_pathspec_magic(x) sane_istest(x,GIT_PATHSPEC_MAGIC)
+
+static inline int sane_case(int x, int high)
+{
+	if (sane_istest(x, GIT_ALPHA))
+		x = (x & ~0x20) | high;
+	return x;
+}
+
+static inline int sane_iscase(int x, int is_lower)
+{
+	if (!sane_istest(x, GIT_ALPHA))
+		return 0;
+
+	if (is_lower)
+		return (x & 0x20) != 0;
+	else
+		return (x & 0x20) == 0;
+}
+
+/*
+ * Like skip_prefix, but compare case-insensitively. Note that the comparison
+ * is done via tolower(), so it is strictly ASCII (no multi-byte characters or
+ * locale-specific conversions).
+ */
+static inline int skip_iprefix(const char *str, const char *prefix,
+			       const char **out)
+{
+	do {
+		if (!*prefix) {
+			*out = str;
+			return 1;
+		}
+	} while (tolower(*str++) == tolower(*prefix++));
+	return 0;
+}
+
+/*
+ * Like skip_prefix_mem, but compare case-insensitively. Note that the
+ * comparison is done via tolower(), so it is strictly ASCII (no multi-byte
+ * characters or locale-specific conversions).
+ */
+static inline int skip_iprefix_mem(const char *buf, size_t len,
+				   const char *prefix,
+				   const char **out, size_t *outlen)
+{
+	do {
+		if (!*prefix) {
+			*out = buf;
+			*outlen = len;
+			return 1;
+		}
+	} while (len-- > 0 && tolower(*buf++) == tolower(*prefix++));
+	return 0;
+}
+
+static inline int strtoul_ui(char const *s, int base, unsigned int *result)
+{
+	unsigned long ul;
+	char *p;
+
+	errno = 0;
+	/* negative values would be accepted by strtoul */
+	if (strchr(s, '-'))
+		return -1;
+	ul = strtoul(s, &p, base);
+	if (errno || *p || p == s || (unsigned int) ul != ul)
+		return -1;
+	*result = ul;
+	return 0;
+}
+
+static inline int strtol_i(char const *s, int base, int *result)
+{
+	long ul;
+	char *p;
+
+	errno = 0;
+	ul = strtol(s, &p, base);
+	if (errno || *p || p == s || (int) ul != ul)
+		return -1;
+	*result = ul;
+	return 0;
+}
+
+static inline int regexec_buf(const regex_t *preg, const char *buf, size_t size,
+			      size_t nmatch, regmatch_t pmatch[], int eflags)
+{
+	assert(nmatch > 0 && pmatch);
+	pmatch[0].rm_so = 0;
+	pmatch[0].rm_eo = size;
+	return regexec(preg, buf, nmatch, pmatch, eflags | REG_STARTEND);
+}
+
+/*
+ * Our code often opens a path to an optional file, to work on its
+ * contents when we can successfully open it.  We can ignore a failure
+ * to open if such an optional file does not exist, but we do want to
+ * report a failure in opening for other reasons (e.g. we got an I/O
+ * error, or the file is there, but we lack the permission to open).
+ *
+ * Call this function after seeing an error from open() or fopen() to
+ * see if the errno indicates a missing file that we can safely ignore.
+ */
+static inline int is_missing_file_error(int errno_)
+{
+	return (errno_ == ENOENT || errno_ == ENOTDIR);
+}
+
+/*
+ * container_of - Get the address of an object containing a field.
+ *
+ * @ptr: pointer to the field.
+ * @type: type of the object.
+ * @member: name of the field within the object.
+ */
+#define container_of(ptr, type, member) \
+	((type *) ((char *)(ptr) - offsetof(type, member)))
+
+/*
+ * helper function for `container_of_or_null' to avoid multiple
+ * evaluation of @ptr
+ */
+static inline void *container_of_or_null_offset(void *ptr, size_t offset)
+{
+	return ptr ? (char *)ptr - offset : NULL;
+}
+
+/*
+ * like `container_of', but allows returned value to be NULL
+ */
+#define container_of_or_null(ptr, type, member) \
+	(type *)container_of_or_null_offset(ptr, offsetof(type, member))
+
+
+#endif
diff --git a/git-compat-util.h b/git-compat-util.h
index 9898fe9374..c2b92a3033 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -106,51 +106,6 @@ struct strbuf;
 	BUILD_ASSERT_OR_ZERO(0 ? ((*(dst) = *(src)), 0) : \
 				 sizeof(*(dst)) == sizeof(*(src)))
 #endif
-/*
- * ARRAY_SIZE - get the number of elements in a visible array
- * @x: the array whose size you want.
- *
- * This does not work on pointers, or arrays declared as [], or
- * function parameters.  With correct compiler support, such usage
- * will cause a build error (see the build_assert_or_zero macro).
- */
-#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + BARF_UNLESS_AN_ARRAY(x))
-
-#define bitsizeof(x)  (CHAR_BIT * sizeof(x))
-
-#define maximum_signed_value_of_type(a) \
-    (INTMAX_MAX >> (bitsizeof(intmax_t) - bitsizeof(a)))
-
-#define maximum_unsigned_value_of_type(a) \
-    (UINTMAX_MAX >> (bitsizeof(uintmax_t) - bitsizeof(a)))
-
-/*
- * Signed integer overflow is undefined in C, so here's a helper macro
- * to detect if the sum of two integers will overflow.
- *
- * Requires: a >= 0, typeof(a) equals typeof(b)
- */
-#define signed_add_overflows(a, b) \
-    ((b) > maximum_signed_value_of_type(a) - (a))
-
-#define unsigned_add_overflows(a, b) \
-    ((b) > maximum_unsigned_value_of_type(a) - (a))
-
-/*
- * Returns true if the multiplication of "a" and "b" will
- * overflow. The types of "a" and "b" must match and must be unsigned.
- * Note that this macro evaluates "a" twice!
- */
-#define unsigned_mult_overflows(a, b) \
-    ((a) && (b) > maximum_unsigned_value_of_type(a) / (a))
-
-/*
- * Returns true if the left shift of "a" by "shift" bits will
- * overflow. The type of "a" must be unsigned.
- */
-#define unsigned_left_shift_overflows(a, shift) \
-    ((shift) < bitsizeof(a) && \
-     (a) > maximum_unsigned_value_of_type(a) >> (shift))
 
 #ifdef __GNUC__
 #define TYPEOF(x) (__typeof__(x))
@@ -158,14 +113,6 @@ struct strbuf;
 #define TYPEOF(x)
 #endif
 
-#define MSB(x, bits) ((x) & TYPEOF(x)(~0ULL << (bitsizeof(x) - (bits))))
-#define HAS_MULTI_BITS(i)  ((i) & ((i) - 1))  /* checks if an integer has more than 1 bit set */
-
-#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
-
-/* Approximation of the length of the decimal representation of this type. */
-#define decimal_length(x)	((int)(sizeof(x) * 2.56 + 0.5) + 1)
-
 #ifdef __MINGW64__
 #define _POSIX_C_SOURCE 1
 #elif defined(__sun__)
@@ -678,88 +625,6 @@ void set_warn_routine(report_fn routine);
 report_fn get_warn_routine(void);
 void set_die_is_recursing_routine(int (*routine)(void));
 
-/*
- * If the string "str" begins with the string found in "prefix", return 1.
- * The "out" parameter is set to "str + strlen(prefix)" (i.e., to the point in
- * the string right after the prefix).
- *
- * Otherwise, return 0 and leave "out" untouched.
- *
- * Examples:
- *
- *   [extract branch name, fail if not a branch]
- *   if (!skip_prefix(ref, "refs/heads/", &branch)
- *	return -1;
- *
- *   [skip prefix if present, otherwise use whole string]
- *   skip_prefix(name, "refs/heads/", &name);
- */
-static inline int skip_prefix(const char *str, const char *prefix,
-			      const char **out)
-{
-	do {
-		if (!*prefix) {
-			*out = str;
-			return 1;
-		}
-	} while (*str++ == *prefix++);
-	return 0;
-}
-
-/*
- * Like skip_prefix, but promises never to read past "len" bytes of the input
- * buffer, and returns the remaining number of bytes in "out" via "outlen".
- */
-static inline int skip_prefix_mem(const char *buf, size_t len,
-				  const char *prefix,
-				  const char **out, size_t *outlen)
-{
-	size_t prefix_len = strlen(prefix);
-	if (prefix_len <= len && !memcmp(buf, prefix, prefix_len)) {
-		*out = buf + prefix_len;
-		*outlen = len - prefix_len;
-		return 1;
-	}
-	return 0;
-}
-
-/*
- * If buf ends with suffix, return 1 and subtract the length of the suffix
- * from *len. Otherwise, return 0 and leave *len untouched.
- */
-static inline int strip_suffix_mem(const char *buf, size_t *len,
-				   const char *suffix)
-{
-	size_t suflen = strlen(suffix);
-	if (*len < suflen || memcmp(buf + (*len - suflen), suffix, suflen))
-		return 0;
-	*len -= suflen;
-	return 1;
-}
-
-/*
- * If str ends with suffix, return 1 and set *len to the size of the string
- * without the suffix. Otherwise, return 0 and set *len to the size of the
- * string.
- *
- * Note that we do _not_ NUL-terminate str to the new length.
- */
-static inline int strip_suffix(const char *str, const char *suffix, size_t *len)
-{
-	*len = strlen(str);
-	return strip_suffix_mem(str, len, suffix);
-}
-
-#define SWAP(a, b) do {						\
-	void *_swap_a_ptr = &(a);				\
-	void *_swap_b_ptr = &(b);				\
-	unsigned char _swap_buffer[sizeof(a)];			\
-	memcpy(_swap_buffer, _swap_a_ptr, sizeof(a));		\
-	memcpy(_swap_a_ptr, _swap_b_ptr, sizeof(a) +		\
-	       BUILD_ASSERT_OR_ZERO(sizeof(a) == sizeof(b)));	\
-	memcpy(_swap_b_ptr, _swap_buffer, sizeof(a));		\
-} while (0)
-
 #if defined(NO_MMAP) || defined(USE_WIN32_MMAP)
 
 #ifndef PROT_READ
@@ -965,57 +830,6 @@ const char *inet_ntop(int af, const void *src, char *dst, size_t size);
 int git_atexit(void (*handler)(void));
 #endif
 
-static inline size_t st_add(size_t a, size_t b)
-{
-	if (unsigned_add_overflows(a, b))
-		die("size_t overflow: %"PRIuMAX" + %"PRIuMAX,
-		    (uintmax_t)a, (uintmax_t)b);
-	return a + b;
-}
-#define st_add3(a,b,c)   st_add(st_add((a),(b)),(c))
-#define st_add4(a,b,c,d) st_add(st_add3((a),(b),(c)),(d))
-
-static inline size_t st_mult(size_t a, size_t b)
-{
-	if (unsigned_mult_overflows(a, b))
-		die("size_t overflow: %"PRIuMAX" * %"PRIuMAX,
-		    (uintmax_t)a, (uintmax_t)b);
-	return a * b;
-}
-
-static inline size_t st_sub(size_t a, size_t b)
-{
-	if (a < b)
-		die("size_t underflow: %"PRIuMAX" - %"PRIuMAX,
-		    (uintmax_t)a, (uintmax_t)b);
-	return a - b;
-}
-
-static inline size_t st_left_shift(size_t a, unsigned shift)
-{
-	if (unsigned_left_shift_overflows(a, shift))
-		die("size_t overflow: %"PRIuMAX" << %u",
-		    (uintmax_t)a, shift);
-	return a << shift;
-}
-
-static inline unsigned long cast_size_t_to_ulong(size_t a)
-{
-	if (a != (unsigned long)a)
-		die("object too large to read on this platform: %"
-		    PRIuMAX" is cut off to %lu",
-		    (uintmax_t)a, (unsigned long)a);
-	return (unsigned long)a;
-}
-
-static inline int cast_size_t_to_int(size_t a)
-{
-	if (a > INT_MAX)
-		die("number too large to represent as int on this platform: %"PRIuMAX,
-		    (uintmax_t)a);
-	return (int)a;
-}
-
 /*
  * Limit size of IO chunks, because huge chunks only cause pain.  OS X
  * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
@@ -1047,240 +861,10 @@ static inline int cast_size_t_to_int(size_t a)
 # define xalloca_free(p)    (free(p))
 #endif
 
-/*
- * FREE_AND_NULL(ptr) is like free(ptr) followed by ptr = NULL. Note
- * that ptr is used twice, so don't pass e.g. ptr++.
- */
-#define FREE_AND_NULL(p) do { free(p); (p) = NULL; } while (0)
-
-#define ALLOC_ARRAY(x, alloc) (x) = xmalloc(st_mult(sizeof(*(x)), (alloc)))
-#define CALLOC_ARRAY(x, alloc) (x) = xcalloc((alloc), sizeof(*(x)))
-#define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc)))
-
-#define COPY_ARRAY(dst, src, n) copy_array((dst), (src), (n), sizeof(*(dst)) + \
-	BARF_UNLESS_COPYABLE((dst), (src)))
-static inline void copy_array(void *dst, const void *src, size_t n, size_t size)
-{
-	if (n)
-		memcpy(dst, src, st_mult(size, n));
-}
-
-#define MOVE_ARRAY(dst, src, n) move_array((dst), (src), (n), sizeof(*(dst)) + \
-	BARF_UNLESS_COPYABLE((dst), (src)))
-static inline void move_array(void *dst, const void *src, size_t n, size_t size)
-{
-	if (n)
-		memmove(dst, src, st_mult(size, n));
-}
-
-#define DUP_ARRAY(dst, src, n) do { \
-	size_t dup_array_n_ = (n); \
-	COPY_ARRAY(ALLOC_ARRAY((dst), dup_array_n_), (src), dup_array_n_); \
-} while (0)
-
-/*
- * These functions help you allocate structs with flex arrays, and copy
- * the data directly into the array. For example, if you had:
- *
- *   struct foo {
- *     int bar;
- *     char name[FLEX_ARRAY];
- *   };
- *
- * you can do:
- *
- *   struct foo *f;
- *   FLEX_ALLOC_MEM(f, name, src, len);
- *
- * to allocate a "foo" with the contents of "src" in the "name" field.
- * The resulting struct is automatically zero'd, and the flex-array field
- * is NUL-terminated (whether the incoming src buffer was or not).
- *
- * The FLEXPTR_* variants operate on structs that don't use flex-arrays,
- * but do want to store a pointer to some extra data in the same allocated
- * block. For example, if you have:
- *
- *   struct foo {
- *     char *name;
- *     int bar;
- *   };
- *
- * you can do:
- *
- *   struct foo *f;
- *   FLEXPTR_ALLOC_STR(f, name, src);
- *
- * and "name" will point to a block of memory after the struct, which will be
- * freed along with the struct (but the pointer can be repointed anywhere).
- *
- * The *_STR variants accept a string parameter rather than a ptr/len
- * combination.
- *
- * Note that these macros will evaluate the first parameter multiple
- * times, and it must be assignable as an lvalue.
- */
-#define FLEX_ALLOC_MEM(x, flexname, buf, len) do { \
-	size_t flex_array_len_ = (len); \
-	(x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
-	memcpy((void *)(x)->flexname, (buf), flex_array_len_); \
-} while (0)
-#define FLEXPTR_ALLOC_MEM(x, ptrname, buf, len) do { \
-	size_t flex_array_len_ = (len); \
-	(x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
-	memcpy((x) + 1, (buf), flex_array_len_); \
-	(x)->ptrname = (void *)((x)+1); \
-} while(0)
-#define FLEX_ALLOC_STR(x, flexname, str) \
-	FLEX_ALLOC_MEM((x), flexname, (str), strlen(str))
-#define FLEXPTR_ALLOC_STR(x, ptrname, str) \
-	FLEXPTR_ALLOC_MEM((x), ptrname, (str), strlen(str))
-
-static inline char *xstrdup_or_null(const char *str)
-{
-	return str ? xstrdup(str) : NULL;
-}
-
-static inline size_t xsize_t(off_t len)
-{
-	if (len < 0 || (uintmax_t) len > SIZE_MAX)
-		die("Cannot handle files this big");
-	return (size_t) len;
-}
-
 #ifndef HOST_NAME_MAX
 #define HOST_NAME_MAX 256
 #endif
 
-/* in ctype.c, for kwset users */
-extern const unsigned char tolower_trans_tbl[256];
-
-/* Sane ctype - no locale, and works with signed chars */
-#undef isascii
-#undef isspace
-#undef isdigit
-#undef isalpha
-#undef isalnum
-#undef isprint
-#undef islower
-#undef isupper
-#undef tolower
-#undef toupper
-#undef iscntrl
-#undef ispunct
-#undef isxdigit
-
-extern const unsigned char sane_ctype[256];
-extern const signed char hexval_table[256];
-#define GIT_SPACE 0x01
-#define GIT_DIGIT 0x02
-#define GIT_ALPHA 0x04
-#define GIT_GLOB_SPECIAL 0x08
-#define GIT_REGEX_SPECIAL 0x10
-#define GIT_PATHSPEC_MAGIC 0x20
-#define GIT_CNTRL 0x40
-#define GIT_PUNCT 0x80
-#define sane_istest(x,mask) ((sane_ctype[(unsigned char)(x)] & (mask)) != 0)
-#define isascii(x) (((x) & ~0x7f) == 0)
-#define isspace(x) sane_istest(x,GIT_SPACE)
-#define isdigit(x) sane_istest(x,GIT_DIGIT)
-#define isalpha(x) sane_istest(x,GIT_ALPHA)
-#define isalnum(x) sane_istest(x,GIT_ALPHA | GIT_DIGIT)
-#define isprint(x) ((x) >= 0x20 && (x) <= 0x7e)
-#define islower(x) sane_iscase(x, 1)
-#define isupper(x) sane_iscase(x, 0)
-#define is_glob_special(x) sane_istest(x,GIT_GLOB_SPECIAL)
-#define is_regex_special(x) sane_istest(x,GIT_GLOB_SPECIAL | GIT_REGEX_SPECIAL)
-#define iscntrl(x) (sane_istest(x,GIT_CNTRL))
-#define ispunct(x) sane_istest(x, GIT_PUNCT | GIT_REGEX_SPECIAL | \
-		GIT_GLOB_SPECIAL | GIT_PATHSPEC_MAGIC)
-#define isxdigit(x) (hexval_table[(unsigned char)(x)] != -1)
-#define tolower(x) sane_case((unsigned char)(x), 0x20)
-#define toupper(x) sane_case((unsigned char)(x), 0)
-#define is_pathspec_magic(x) sane_istest(x,GIT_PATHSPEC_MAGIC)
-
-static inline int sane_case(int x, int high)
-{
-	if (sane_istest(x, GIT_ALPHA))
-		x = (x & ~0x20) | high;
-	return x;
-}
-
-static inline int sane_iscase(int x, int is_lower)
-{
-	if (!sane_istest(x, GIT_ALPHA))
-		return 0;
-
-	if (is_lower)
-		return (x & 0x20) != 0;
-	else
-		return (x & 0x20) == 0;
-}
-
-/*
- * Like skip_prefix, but compare case-insensitively. Note that the comparison
- * is done via tolower(), so it is strictly ASCII (no multi-byte characters or
- * locale-specific conversions).
- */
-static inline int skip_iprefix(const char *str, const char *prefix,
-			       const char **out)
-{
-	do {
-		if (!*prefix) {
-			*out = str;
-			return 1;
-		}
-	} while (tolower(*str++) == tolower(*prefix++));
-	return 0;
-}
-
-/*
- * Like skip_prefix_mem, but compare case-insensitively. Note that the
- * comparison is done via tolower(), so it is strictly ASCII (no multi-byte
- * characters or locale-specific conversions).
- */
-static inline int skip_iprefix_mem(const char *buf, size_t len,
-				   const char *prefix,
-				   const char **out, size_t *outlen)
-{
-	do {
-		if (!*prefix) {
-			*out = buf;
-			*outlen = len;
-			return 1;
-		}
-	} while (len-- > 0 && tolower(*buf++) == tolower(*prefix++));
-	return 0;
-}
-
-static inline int strtoul_ui(char const *s, int base, unsigned int *result)
-{
-	unsigned long ul;
-	char *p;
-
-	errno = 0;
-	/* negative values would be accepted by strtoul */
-	if (strchr(s, '-'))
-		return -1;
-	ul = strtoul(s, &p, base);
-	if (errno || *p || p == s || (unsigned int) ul != ul)
-		return -1;
-	*result = ul;
-	return 0;
-}
-
-static inline int strtol_i(char const *s, int base, int *result)
-{
-	long ul;
-	char *p;
-
-	errno = 0;
-	ul = strtol(s, &p, base);
-	if (errno || *p || p == s || (int) ul != ul)
-		return -1;
-	*result = ul;
-	return 0;
-}
-
 void git_stable_qsort(void *base, size_t nmemb, size_t size,
 		      int(*compar)(const void *, const void *));
 #ifdef INTERNAL_QSORT
@@ -1313,15 +897,6 @@ int git_qsort_s(void *base, size_t nmemb, size_t size,
 #error "Git requires REG_STARTEND support. Compile with NO_REGEX=NeedsStartEnd"
 #endif
 
-static inline int regexec_buf(const regex_t *preg, const char *buf, size_t size,
-			      size_t nmatch, regmatch_t pmatch[], int eflags)
-{
-	assert(nmatch > 0 && pmatch);
-	pmatch[0].rm_so = 0;
-	pmatch[0].rm_eo = size;
-	return regexec(preg, buf, nmatch, pmatch, eflags | REG_STARTEND);
-}
-
 #ifdef USE_ENHANCED_BASIC_REGULAR_EXPRESSIONS
 int git_regcomp(regex_t *preg, const char *pattern, int cflags);
 #define regcomp git_regcomp
@@ -1430,21 +1005,6 @@ int git_access(const char *path, int mode);
 # endif
 #endif
 
-/*
- * Our code often opens a path to an optional file, to work on its
- * contents when we can successfully open it.  We can ignore a failure
- * to open if such an optional file does not exist, but we do want to
- * report a failure in opening for other reasons (e.g. we got an I/O
- * error, or the file is there, but we lack the permission to open).
- *
- * Call this function after seeing an error from open() or fopen() to
- * see if the errno indicates a missing file that we can safely ignore.
- */
-static inline int is_missing_file_error(int errno_)
-{
-	return (errno_ == ENOENT || errno_ == ENOTDIR);
-}
-
 int cmd_main(int, const char **);
 
 /*
@@ -1486,37 +1046,14 @@ int uncompress2(Bytef *dest, uLongf *destLen, const Bytef *source,
 		uLong *sourceLen);
 #endif
 
+#include "common.h"
+
 /*
  * This include must come after system headers, since it introduces macros that
  * replace system names.
  */
 #include "banned.h"
 
-/*
- * container_of - Get the address of an object containing a field.
- *
- * @ptr: pointer to the field.
- * @type: type of the object.
- * @member: name of the field within the object.
- */
-#define container_of(ptr, type, member) \
-	((type *) ((char *)(ptr) - offsetof(type, member)))
-
-/*
- * helper function for `container_of_or_null' to avoid multiple
- * evaluation of @ptr
- */
-static inline void *container_of_or_null_offset(void *ptr, size_t offset)
-{
-	return ptr ? (char *)ptr - offset : NULL;
-}
-
-/*
- * like `container_of', but allows returned value to be NULL
- */
-#define container_of_or_null(ptr, type, member) \
-	(type *)container_of_or_null_offset(ptr, offsetof(type, member))
-
 /*
  * like offsetof(), but takes a pointer to a variable of type which
  * contains @member, instead of a specified type.
