Method, device and computer program product for searching a file
Embodiments of the present disclosure provide method, device and computer program product for file search. The method for file search comprises: determining a hash value associated with an identification of a file to be searched; determining, from a plurality of candidate location chains, a target location chain associated with the hash value; determining, from the target location chain, a target element based on the identification, the target element indicating an address of the file to be searched in a memory; and acquiring the file from the memory based on the address.
1. A method of searching a file, comprising:
determining a hash value associated with an identification of a file to be searched via SHA-1 algorithm;
generating a plurality of candidate location chains and a plurality of address arrays associated with the plurality of candidate location chains, each of the plurality of address arrays storing the hash value and an address of the plurality of candidate location chains, wherein an address of a candidate element in the file to be searched is added into the plurality of candidate location chains;
determining, from the plurality of candidate location chains, a target location chain associated with the hash value;
determining, from the target location chain, a target element based on the identification, the target element including a file name and an address of the target element for the file to be searched in a memory, the address of the target element in the target location pointing to an address of a corresponding target element in a container of the file to be searched, wherein determining the target location chain comprises:
selecting a candidate location chain from the plurality of candidate location chains based on the address of the plurality of candidate location chains stored in the plurality of address arrays, the selected candidate location chain having a candidate hash value, the candidate hash value being determined based on a particular hash value corresponding to an element in the selected candidate location chain, and
in response to the particular hash value being matched with the candidate hash value, determining the selected candidate location chain as the target location chain; and
acquiring the file from the memory based on the address of the target element.
2. The method of claim 1 , wherein determining the hash value comprises:
calculating an initial hash value based on the identification; and
selecting, from the initial hash value, a predetermined number of consecutive bits as the hash value.
3. The method of claim 2 , wherein selecting from the initial hash value the predetermined number of consecutive bits comprises:
selecting the predetermined number of consecutive bits starting from a lowest bit of the initial hash value.
4. The method of claim 3 , wherein the initial hash value has 160 bits, and wherein the predetermined number of consecutive bits is 12.
5. The method of claim 2 , wherein selecting from the initial hash value the predetermined number of consecutive bits comprises:
selecting the predetermined number of consecutive bits starting from a lowest bit of the initial hash value.
6. The method of claim 1 , wherein determining from the target location chain the target element comprises:
determining candidate identifications comprised in respective elements of the target location chain; and
in response to the identification being matched with one of the candidate identifications, determining an element corresponding to the matched candidate identification as the target element.
7. The method of claim 1 , further comprising:
acquiring a location of the file to be searched in a backup server, wherein the file to be searched is utilized for a backup process; and
generating a backup for an image file and an altered block file of the backup process based on the file to be searched.
8. The method of claim 7 , wherein the location of the file to be searched is represented by a ddr_file in the backup server, and wherein the file to be searched is stored in the container.
9. A device for searching a file, comprising:
a processing unit;
a memory coupled to the processing unit and stored with instructions, the instructions, when executed by the processing unit, perform following actions of:
determining a hash value associated with an identification of a file to be searched via SHA-1 algorithm;
generating a plurality of candidate location chains and a plurality of address arrays associated with the plurality of candidate location chains, each of the plurality of address arrays storing the hash value and an address of the plurality of candidate location chains, wherein an address of a candidate element in the file to be searched is added into the plurality of candidate location chains;
selecting, from the plurality of candidate location chains, a target location chain associated with the hash value;
determining, from the target location chain, a target element based on the identification, the target element including a file name and an address of the target element for the file to be searched in the memory, the address of the target element in the target location pointing to an address of a corresponding target element in a container of the file to be searched, wherein determining the target location chain comprises:
selecting a candidate location chain from the plurality of candidate location chains based on the address of the plurality of candidate location chains stored in the plurality of address arrays, the selected candidate location chain having a candidate hash value, the candidate hash value being determined based on a particular hash value corresponding to an element in the selected candidate location chain, and
in response to the particular hash value being matched with the candidate hash value, determining the selected candidate location chain as the target location chain; and
acquiring the file from the memory based on the address of the target element.
10. The device of claim 9 , wherein determining the hash value comprises:
calculating an initial hash value based on the identification; and
selecting, from the initial hash value, a predetermined number of consecutive bits as the hash value.
11. The device of claim 10 , wherein selecting from the initial hash value the predetermined number of consecutive bits comprises:
selecting the predetermined number of consecutive bits starting from a lowest bit of the initial hash value.
12. The device of claim 9 , wherein determining from the target location chain the target element comprises:
determining candidate identifications comprised in respective elements of the target location chain; and
in response to the identification being matched with one of the candidate identifications, determining an element corresponding to the matched candidate identification as the target element.
13. A non-transitory machine-readable medium having instructions stored therein, which when executed by a processor, cause the processor to perform operations, the operations comprising:
determining a hash value associated with an identification of a file to be searched via SHA-1 algorithm;
generating a plurality of candidate location chains and a plurality of address arrays associated with the plurality of candidate location chains, each of the plurality of address arrays storing the hash value and an address of the plurality of candidate location chains, wherein an address of a candidate element in the file to be searched is added into the plurality of candidate location chains;
determining, from the plurality of candidate location chains, a target location chain associated with the hash value;
determining, from the target location chain, a target element based on the identification, the target element including a file name and an address of the target element for the file to be searched in a memory, the address of the target element in the target location pointing to an address of a corresponding target element in a container of the file to be searched, wherein determining the target location chain comprises:
selecting a candidate location chain from the plurality of candidate location chains based on the address of the plurality of candidate location chains stored in the plurality of address arrays, the selected candidate location chain having a candidate hash value, the candidate hash value being determined based on a particular hash value corresponding to an element in the selected candidate location chain, and
in response to the particular hash value being matched with the candidate hash value, determining the selected candidate location chain as the target location chain; and
acquiring the file from the memory based on the address of the target element.
14. The machine-readable medium of claim 13 , wherein determining the hash value comprises:
calculating an initial hash value based on the identification; and
selecting, from the initial hash value, a predetermined number of consecutive bits as the hash value.
15. The machine-readable medium of claim 13 , wherein determining from the target location chain the target element comprises:
determining candidate identifications comprised in respective elements of the target location chain; and
in response to the identification being matched with one of the candidate identifications, determining an element corresponding to the matched candidate identification as the target element.