Branch 選項(xiàng)會(huì)給開(kāi)發(fā)者創(chuàng)建出另外一條線路。當(dāng)有人希望開(kāi)發(fā)進(jìn)程分開(kāi)成兩條不同的線路時(shí)，這個(gè)選項(xiàng)會(huì)非常有用。我們先假設(shè)你已經(jīng)發(fā)布了一個(gè)產(chǎn)品的 1.0 版本，你可能想創(chuàng)建一個(gè)新的分支，這樣就可以不干擾到 1.0 版本的bug修復(fù)的同時(shí)，又可以開(kāi)發(fā)2.0版本。
在這一節(jié)，我們將看到如何創(chuàng)建，穿過(guò)和合并分支。Jerry 因?yàn)榇a沖突的事情不開(kāi)心，所以他決定創(chuàng)建一個(gè)新的私有分支。
[jerry@CentOS project_repo]$ ls
branches tags trunk
[jerry@CentOS project_repo]$ svn copy trunk branches/jerry_branch
A branches/jerry_branch
[jerry@CentOS project_repo]$ svn status
A + branches/jerry_branch
[jerry@CentOS project_repo]$ svn commit -m "Jerry's private branch"
Adding branches/jerry_branch
Adding branches/jerry_branch/README
Committed revision 9.
[jerry@CentOS project_repo]$ 現(xiàn)在 Jerry 在自己的分支下開(kāi)始工作。他給序列添加了 sort 選項(xiàng)。Jerry 修改后的代碼如下：
[jerry@CentOS project_repo]$ cd branches/jerry_branch/
[jerry@CentOS jerry_branch]$ cat array.c 上面的代碼將會(huì)產(chǎn)生下面的結(jié)果：
#include <stdio.h>
#define MAX 16
void bubble_sort(int *arr, int n)
{
int i, j, temp, flag = 1;
for (i = 1; i < n && flag == 1; ++i) {
flag = 0;
for (j = 0; j < n - i; ++j) {
if (arr[j] > arr[j + 1]) {
flag = 1;
temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
void accept_input(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
scanf("%d", &arr[i]);
}
void display(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
printf("|%d| ", arr[i]);
printf("\n");
}
int main(void)
{
int i, n, key, ret, arr[MAX];
printf("Enter the total number of elements: ");
scanf("%d", &n);
/* Error handling for array overflow */
if (n >MAX) {
fprintf(stderr, "Number of elements must be less than %d\n", MAX);
return 1;
}
printf("Enter the elements\n");
accept_input(arr, n);
printf("Array has following elements\n");
display(arr, n);
printf("Sorted data is\n");
bubble_sort(arr, n);
display(arr, n);
return 0;
}Jerry 編譯并且測(cè)試了他的代碼，準(zhǔn)備提交他的更改。
[jerry@CentOS jerry_branch]$ make array
cc array.c -o array
[jerry@CentOS jerry_branch]$ ./array 上面的命令將會(huì)產(chǎn)生如下的結(jié)果：
Enter the total number of elements: 5
Enter the elements
10
-4
2
7
9
Array has following elements
|10| |-4| |2| |7| |9|
Sorted data is
|-4| |2| |7| |9| |10|
[jerry@CentOS jerry_branch]$ svn status
? array
M array.c
[jerry@CentOS jerry_branch]$ svn commit -m "Added sort operation"
Sending jerry_branch/array.c
Transmitting file data .
Committed revision 10.同時(shí)，越過(guò)主干，Tom 決定實(shí)現(xiàn) search 選項(xiàng)。Tom 添加了 search 選項(xiàng)而添加代碼，他的代碼如下：
[tom@CentOS trunk]$ svn diff上面的命令將會(huì)產(chǎn)生下面的結(jié)果：
Index: array.c
===================================================================
--- array.c (revision 10)
+++ array.c (working copy)
@@ -2,6 +2,27 @@
#define MAX 16
+int bin_search(int *arr, int n, int key)
+{
+ int low, high, mid;
+
+ low = 0;
+ high = n - 1;
+ mid = low + (high - low) / 2;
+
+ while (low <= high) {
+ if (arr[mid] == key)
+ return mid;
+ if (arr[mid] > key)
+ high = mid - 1;
+ else
+ low = mid + 1;
+ mid = low + (high - low) / 2;
+ }
+
+ return -1;
+}
+
void accept_input(int *arr, int n)
{
int i;
@@ -22,7 +43,7 @@
int main(void)
{
- int i, n, arr[MAX];
+ int i, n, ret, key, arr[MAX];
printf("Enter the total number of elements: ");
scanf("%d", &n);
@@ -39,5 +60,16 @@
printf("Array has following elements\n");
display(arr, n);
+ printf("Enter the element to be searched: ");
+ scanf("%d", &key);
+
+ ret = bin_search(arr, n, key);
+ if (ret < 0) {
+ fprintf(stderr, "%d element not present in array\n", key);
+ return 1;
+ }
+
+ printf("%d element found at location %d\n", key, ret + 1);
+
return 0;
}
After reviewing, he commits his changes.
[tom@CentOS trunk]$ svn status
? array
M array.c
[tom@CentOS trunk]$ svn commit -m "Added search operation"
Sending trunk/array.c
Transmitting file data .
Committed revision 11.但是 Tom 好奇 Jerry 在他自己的私有分支中干了什么：
[tom@CentOS trunk]$ cd ../branches/
[tom@CentOS branches]$ svn up
A jerry_branch
A jerry_branch/array.c
A jerry_branch/README
[tom@CentOS branches]$ svn log
------------------------------------------------------------------------
r9 | jerry | 2013-08-27 21:56:51 +0530 (Tue, 27 Aug 2013) | 1 line
Added sort operation
------------------------------------------------------------------------通過(guò)查看 Subversion 的 log 信息，Tom 發(fā)現(xiàn) Jerry 依賴(lài) ‘sort’ 選項(xiàng)。Tom 決定增添用折半查找，期望數(shù)據(jù)總是根據(jù)種類(lèi)進(jìn)行分類(lèi)。但是如果用戶提供的數(shù)據(jù)是沒(méi)有進(jìn)行分類(lèi)呢？在那種情況下，折半查找將會(huì)失效。所以他決定接著 Jerry 的代碼，在搜索選項(xiàng)前先進(jìn)性分類(lèi)。所以他告訴 Subversion 合并 Jerry 的分支到主干中去。
[tom@CentOS trunk]$ pwd
/home/tom/project_repo/trunk
[tom@CentOS trunk]$ svn merge ../branches/jerry_branch/
--- Merging r9 through r11 into '.':
U array.c在融合后，array.c 會(huì)看上去是這個(gè)樣子：
[tom@CentOS trunk]$ cat array.c上面的代碼將會(huì)產(chǎn)生下面的結(jié)果：
#include <stdio.h>
#define MAX 16
void bubble_sort(int *arr, int n)
{
int i, j, temp, flag = 1;
for (i = 1; i < n && flag == 1; ++i) {
flag = 0;
for (j = 0; j < n - i; ++j) {
if (arr[j] > arr[j + 1]) {
flag = 1;
temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
int bin_search(int *arr, int n, int key)
{
int low, high, mid;
low = 0;
high = n - 1;
mid = low + (high - low) / 2;
while (low <= high) {
if (arr[mid] == key)
return mid;
if (arr[mid] > key)
high = mid - 1;
else
low = mid + 1;
mid = low + (high - low) / 2;
}
return -1;
}
void accept_input(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
scanf("%d", &arr[i]);
}
void display(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
printf("|%d| ", arr[i]);
printf("\n");
}
int main(void)
{
int i, n, ret, key, arr[MAX];
printf("Enter the total number of elements: ");
scanf("%d", &n);
/* Error handling for array overflow */
if (n > MAX) {
fprintf(stderr, "Number of elements must be less than %d\n", MAX);
return 1;
}
printf("Enter the elements\n");
accept_input(arr, n);
printf("Array has following elements\n");
display(arr, n);
printf("Sorted data is\n");
bubble_sort(arr, n);
display(arr, n);
printf("Enter the element to be searched: ");
scanf("%d", &key);
ret = bin_search(arr, n, key);
if (ret < 0) {
fprintf(stderr, "%d element not present in array\n", key);
return 1;
}
printf("%d element found at location %d\n", key, ret + 1);
return 0;
}經(jīng)過(guò)編譯和測(cè)試后，Tom 提交了他的更改到倉(cāng)庫(kù)。
[tom@CentOS trunk]$ make array
cc array.c -o array
[tom@CentOS trunk]$ ./array
Enter the total number of elements: 5
Enter the elements
10
-2
8
15
3
Array has following elements
|10| |-2| |8| |15| |3|
Sorted data is
|-2| |3| |8| |10| |15|
Enter the element to be searched: -2
-2 element found at location 1
[tom@CentOS trunk]$ svn commit -m "Merge changes from Jerry's code"
Sending trunk
Sending trunk/array.c
Transmitting file data .
Committed revision 12.
[tom@CentOS trunk]$ 
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